Bipedialism and other factors and AAT
Sir CPU
locomotion in comparison to other animals. Much has been claimed
in this news group that humans have an efficient means of
locomotion. That might be somewhat true for walking, but it is NOT
true for running, especially in comparison to other animals. I think
this would present some problems on an open African savanna environment.
Much of this information is taken from The Cambridge Encyclopedia of
Human Evolution, Cambridge University Press, copyright 1992
There is apparently no clear difference in the efficiency of locomotion
of bipeds in comparison to quadrupeds, this is according to R. McNeill
Alexander. This is something I did not realize. And as a GENERAL
statement it is true. But only because it includes such efficient
bipeds as ostriches and kangaroos, of which the later uses a totally
different means of locomotion than humans do.
This "efficiency rating" based on the formula P = P(o) + C(v)
Where P = power
P(o) = power used when stationary
V = Speed
C = Energy used in traveling a unit distance, over and above
what would be used if standing still
This formula reveals that "some species are unusually economical for
their size, whereas other are unusually extravagant of energy. For
example, a penguin which waddles in an ungainly way, uses
proportionately twice as much energy for traveling overland as a
graceful gazelle."
And guess where humans fall??
Slightly better than the penguin, but not quite as good as a pony,
which apparently is a rather inefficient quadruped for it's size. The a
formula also shows that "running is a little more costly for us than
for typical mammals of equal body weight. Human walking is less
costly."
Those grouped into the efficient column, using this formula would be
the quail, the dog, the gazelle, and the ostrich. Those in the
inefficient
group would be the goose, the penguin, the human, and the pony.
So as long as we did not have to run from any predators, we were OK.
According to R. McNeill Alexander, "Not only are we rather
uneconomical runners, we are also rather slow"
Combine this with the problem of sweating, and you have an animal
that is slow, and inefficient at moving with any significant degree of
speed, and needs to be near water to replenish lost fluids.
The fact is that "Active young men will normally lose over 8 litres of
water during a day when the desert temperature at midday is above
40 C." "A man weighing 90 kilograms can sweat over 2 liters of water
in an hour of normal walking in a hot day in the desert."
It would seem to me that since we were, and still are not a
particularly fast or agile creature; combined with our tendency to
suffer from a high degree of dehydration that occurs in moderately
hot climates; combined with an unusually hairless body; combined
with eyes that make it possible to only become active during the
light of day and not the coolness of night; combined with not
especially good hearing when compared with other creatures who
can hear over the vast distances of the great plains; would lead one
to the conclusion that we must have evolved in a safe, shady, semi-
aquatic environment.
Troy Kelley
John D. Brennan IV
sir...@aol.com (Sir CPU) writes:
> According to R. McNeill Alexander, "Not only are we rather
> uneconomical runners, we are also rather slow"
Troy,
Perhaps I'm mistaken, but I believe that the same arguement was used
as evidence that chimps were just a leftover of the evolution of man.
Later they found out that a chimp was highly efficient and evolved for
walking along a branch/line not the ground, just like another
"inefficient" species, squirrels (who are slow "bouncy" runners but
greased lightening in a tree). The point is, man evolved to walk, not
run, it's what we do best, just like the other "inefficient" species
you mentioned, penguins, who are extremely efficient in the water. So
to recap, man's mode of transportation is walking, just like chimps and
squirrels climb and walk branches, and the penguins swim, running is an
extra and hence inefficient for all of the above.
--John (just an old Bio/Anthro major, fire at will! (smile))
HARRY R. ERWIN
of a six-year-old (with at best comparable mobility), but the comparison
should be with quadrupeds of the same leg-length and approximate mass, not
with modern man. Efficiency and range will be comparable then. The
interesting point is that a biped has two advantages over the quadruped:
the head is about twice as far off the ground, and the hands and arms do
not need to be modified for terrestrial support. Based on mechanical
factors, Lucy and OH-62 had comparable forearm climbing abilities to
orangs and were superior to gorillas and chimps. (The fingers and palms of
knuckle-walkers are modified for compressive strength. This reduces their
efficiency at grasping tree limbs.)
--
Harry Erwin
Internet: her...@gmu.edu
PhD student in comp neurosci: "Glitches happen" & "Meaning is emotional"
Sir CPU
-run, it's what we do best, just like the other "inefficient" species
-you mentioned, penguins, who are extremely efficient in the water. So
-to recap, man's mode of transportation is walking, just like chimps and
-squirrels climb and walk branches, and the penguins swim, running is an
-extra and hence inefficient for all of the above.
-John (just an old Bio/Anthro major, fire at will! (smile))
The point I was trying to make though is that man's inefficiency of
running is not helpful when being pursued by a predator. And it seems to
me that this would happen often if man evolved for any lenght of time on
the open savannas. It wouldn't matter how efficient walking was, running
it what really counts when a lion is chasing you.
The points you make about other species isn't a good comparison
because all of them are fast at least SOMEWHERE and primarily where they
are most likely to be prusued by predators. Penguins may not be able to
walk efficiently, but the majority of their predators are in the water
(Killer Whales and Leapord Seals). Consequently they manage to out race
their attackers in the water. They are lucky they have no major predators
on land. Perhaps this is why they choose to raise there young out in the
open on land.
Squirrels might not be efficient on the ground, but they are never
far from a tree, and at the first sign of trouble, they make a dash for a
tree. They are obviously vulnerable on the land, and this is where a
predator is most likely to catch a squirrel.
Troy Kelley
Brad Woodcock
*Excessive eradication of post here*
>It would seem to me that since we were, and still are not a
>particularly fast or agile creature; combined with our tendency to
>suffer from a high degree of dehydration that occurs in moderately
>hot climates; combined with an unusually hairless body; combined
>with eyes that make it possible to only become active during the
>light of day and not the coolness of night; combined with not
>especially good hearing when compared with other creatures who
>can hear over the vast distances of the great plains; would lead one
>to the conclusion that we must have evolved in a safe, shady, semi-
>aquatic environment.
>Troy Kelley
This isn't a direct response to this particular post, but it is the thing
that brought this to mind again. Where in the world did this idea come from
that Australos dropped out of the trees and immediately began living
strictly on the savannah far from trees? They were obviously partially
arboreal, and they were tiny! A 40kg creature without any real natural
weaponry isn't much of a threat, overall. Doesn't it make more sense that
Australos lived in the borderlands between savannah and deep forest?
Possibly sleeping in or near trees for safety (as some baboons do), foraging
the borderland, and taking short forays for food farther into the forest,
and also out onto the more flat, less wooded savannah. This demonstrates a
larger variety of food resources, without requiring a huge increase in
foraging distances. I'm not sure what would cause them to move out into the
borderlands though. It could be that the forest was becoming smaller and
they were out competed by something in the forest (like monkeys). I could
just be that they were competed out of the forest by something (once again,
probably monkeys) but didn't quite have what it took to live on the
savannah. Something I've been very curious about, and which I have seen
mostly sidestepped or ignored completely is the question of what kinds of
animals would the A. Afarensis been competing against? What size predators,
and scavengers were around on the savannah, lightly wooded, and forest areas
of eastern Africa 3-2.5mya? This could be very important. If we're talking
about 10 40kg males and 12 30kg females taking on something along the lines
of a giant hyena or a lion something like twice the size of the ones around
today, I think the only recourse they could possibly have is heading into
the trees for safety. Finger nails, small canines and small body weight are
not the weapons I would ask for if I had to try to defend myself from
something that big and nasty. Even if we assume that the intelligence of
the Australopiths was significantly helpful in these situations, and that
they had weapons of some sort, that still makes for a very one sided fight.
--
Brad Woodcock The Trolls Guild
wood...@horus.cecer.army.mil "We're here to make you
brad-...@nova.novanet.org appreciate normal people."
Work:(217)352-6511 x7590 Home:(217)344-0363
HARRY R. ERWIN
: -The point is, man evolved to walk, not
: -run,... (trimmed)
: The point I was trying to make though is that man's inefficiency of
: running is not helpful when being pursued by a predator. And it seems to
: me that this would happen often if man evolved for any lenght of time on
: the open savannas. It wouldn't matter how efficient walking was, running
: it what really counts when a lion is chasing you.
Actually it doesn't matter much by that point. Your likely to be better of
standing your ground (with a few others). What matters is spotting the
lion at a distance. There bipedalism is superior.
: The points you make about other species isn't a good comparison
: because all of them are fast at least SOMEWHERE and primarily where they
: are most likely to be prusued by predators. Penguins may not be able to
: walk efficiently, but the majority of their predators are in the water
: (Killer Whales and Leapord Seals). Consequently they manage to out race
: their attackers in the water. They are lucky they have no major predators
: on land. Perhaps this is why they choose to raise there young out in the
: open on land.
Based on the skeletal features, A. was one hell of a fast tree climber
(equal to Pongo in this regard).
: Squirrels might not be efficient on the ground, but they are never
: far from a tree, and at the first sign of trouble, they make a dash for a
: tree. They are obviously vulnerable on the land, and this is where a
: predator is most likely to catch a squirrel.
: Troy Kelley
--
J. Moore
And, as you've read in my other post(s), we almost certainly did not
have to depend on running for defense from predators. Certainly not
any long distance. So we were, as you state above, okay. But to
realise this, you have to look at what we and our close relatives
actually do, rather than what you would imagine they should do.
Si> Combine this with the problem of sweating, and you have an animal
Si> that is slow, and inefficient at moving with any significant degree of
Si> speed, and needs to be near water to replenish lost fluids.
Si> The fact is that "Active young men will normally lose over 8 litres of
Si> water during a day when the desert temperature at midday is above
Si> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of water
Si> in an hour of normal walking in a hot day in the desert."
First of all, who the hell ever said that australopithecines *ever* set
foot in the desert (besides you)?
Second, look at Peter Wheeler's (1994) statement:
"The estimated total daytime drinking water requirements of a 35 Kg
naked biped, utilising heat storage and foraging throughout the day at
the temperatures and level of metabolic expenditure used in the present
study [note: 35-40 degree C temperatures and a 12 hour foraging day,
rather longer than likely actually], is approximately 1.3 litres, the
equivalent of 3.7% of its total body mass. Since this degree of
dehydration can be tolerated by modern humans without experiencing any
major detrimental effects, this indicates that these animals should not
usually have required access to drinking water more than once a day
(Wheeler, 1991b). If the normal activity pattern of these primates also
involved shade-seeking during the most thermally stressing period of the
day, their requirements will have been substantially lower. Intakes as
low as 0.7 litre, equivalent to only about 2% of total body mass, may
have been sufficient to replace all losses incurred by a naked biped
throughout the day if it retreated into the shade for a 4-hour period in
the early afternoon [note: this is the common mode of activity in hot
climates for humans, chimps, gorillas, and indeed a whole lot of
animals; "mad dogs and Englishmen" and all that]."
Si> can hear over the vast distances of the great plains; would lead one
Si> to the conclusion that we must have evolved in a safe, shady, semi-
Si> aquatic environment.
Si> Troy Kelley
"Shady" at the seashore? You've *never* been to the beach? Safe? From
crocs and sharks we can't even see approaching? And which don't respond
to human and chimpanzee threat displays (as big cats and other land
predators do)?
Jim Moore (j#d#.mo...@canrem.com)
Refs:
Wheeler, Peter
1991b [I don't have the title here at present, sorry]. *Journal of
Human Evolution* 21:117-136
Wheeler, Peter
1994 "The thermoregulatory advantages of heat storage and shade-seeking
behavior to hominids foraging in equatorial savannah environments".
*Journal of Human Evolution* 24(4):339-350, April.
* Q-Blue 1.0 *
Troy Kelley
From: J. Moore, j#d#.mo...@canrem.com
Date: Sat, 3 Jun 95 12:40:00 -0500
In article <60.1658.72...@canrem.com> J. Moore,
j#d#.mo...@canrem.com writes:
>Si> So as long as we did not have to run from any predators, we were OK.
>
>And, as you've read in my other post(s), we almost certainly did not
>have to depend on running for defense from predators. Certainly not
>any long distance. So we were, as you state above, okay. But to
>realise this, you have to look at what we and our close relatives
>actually do, rather than what you would imagine they should do.
If you are talking, in some sort of round about way, about threat
displays, I realize of course that SOME animals exhibit threat displays
when cornered by a predator. By "our close relatives" I assume you mean
chimps and gorrillas, but they are not currently under a lot of predation
except from man. So they exhibit very little predatoral threat displays.
I think you are mainly talking about baboons which exhibit threat
displays as part of a defense, but this is also because they are
primarily savanna creatures which do not have the luxury of running to a
tree every time danger is encountered.
>Si> Combine this with the problem of sweating, and you have an animal
>Si> that is slow, and inefficient at moving with any significant degree
of
>Si> speed, and needs to be near water to replenish lost fluids.
>
>Si> The fact is that "Active young men will normally lose over 8 litres
of
>Si> water during a day when the desert temperature at midday is above
>Si> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of water
>Si> in an hour of normal walking in a hot day in the desert."
>
>First of all, who the hell ever said that australopithecines *ever* set
>foot in the desert (besides you)?
Gee.. I didn't realize I said "Australopithecines set foot in the
desert". Thank you for explaining to me what I said.
I was mearly using a quote I had found about water consumption to
illustrate a point that hominids, when compared to other savanna
creatures, do not conserve water very well.
>
>Second, look at Peter Wheeler's (1994) statement:
>
>"The estimated total daytime drinking water requirements of a 35 Kg
>naked biped, utilising heat storage and foraging throughout the day at
>the temperatures and level of metabolic expenditure used in the present
>study [note: 35-40 degree C temperatures and a 12 hour foraging day,
>rather longer than likely actually], is approximately 1.3 litres, the
>equivalent of 3.7% of its total body mass. Since this degree of
>dehydration can be tolerated by modern humans without experiencing any
>major detrimental effects, this indicates that these animals should not
>usually have required access to drinking water more than once a day
>(Wheeler, 1991b). If the normal activity pattern of these primates also
>involved shade-seeking during the most thermally stressing period of the
>day, their requirements will have been substantially lower. Intakes as
>low as 0.7 litre, equivalent to only about 2% of total body mass, may
>have been sufficient to replace all losses incurred by a naked biped
>throughout the day if it retreated into the shade for a 4-hour period in
>the early afternoon [note: this is the common mode of activity in hot
>climates for humans, chimps, gorillas, and indeed a whole lot of
>animals; "mad dogs and Englishmen" and all that]."
You can use all the quotes on water consumption you want and I promise
you I can find quotes that will contradict you. I did however noticed
that the first part of this reference was an "estimate". I think that
the "estimated total daytime drinking requirements" by this author was a
very poor estimate.
I don't think there is really any question, no matter what quote you come
up with, that the susceptibility of early hominids to dehydration was
probably pretty high. If you look at any other creature on the savanna,
the ways in which they conserve water resources are far superior to the
human/pre-human model. Their body temperatures are generally higher,
they allow their internal body temperatures to rise in response to heat
and they don't sweat, they pant. Sweating may be an efficient cooling
mechanism for humans, but it is not an effective way to stay cool unless
there is access to plenty of water to re-hydrate the body. I really
don't think there is any argument about this.
>
>Si> can hear over the vast distances of the great plains; would lead one
>Si> to the conclusion that we must have evolved in a safe, shady, semi-
>Si> aquatic environment.
>Si> Troy Kelley
>
>"Shady" at the seashore? You've *never* been to the beach? Safe? From
>crocs and sharks we can't even see approaching? And which don't respond
>to human and chimpanzee threat displays (as big cats and other land
>predators do)?
>J. Moore, j#d#.mo...@canrem.com
"You've *never* been to the beach?" - Now theres a good, well thought
out, non-antagonistic question.
And to use one of your previous quotes - "Who the hell said anything
about a seashore?" I don't think DRINKING sea water for re-hydration
would be a very effective way to say alive on the Africa savanna.
And besides that, I don't think crocodiles like salt water, in fact, I
know that they don't live in salt water.
Haven't you ever been to the beach?
Troy Kelley
Drew Talley
[lots deleted]
: And besides that, I don't think crocodiles like salt water, in fact, I
: know that they don't live in salt water.
C. porosus lives almost entirely in the ocean, often swimming several
miles out to sea. Many other species show varying tolerances for
salinity.
Drew
tal...@sunstroke.sdsu.edu
or
dta...@ucsd.edu
: Troy Kelley
J. Moore
Tk> Subject: Re: Bipedialism and other factors and AAT
Tk> X-Xxdate: Tue, 6 Jun 95 13:49:41 GMT
Tk> Subject: Re: Bipedalism and other factors and AAT
Tk> From: J. Moore, j#d#.mo...@canrem.com
Tk> Date: Sat, 3 Jun 95 12:40:00 -0500
Just as a matter of curiousity, why do you continually use the incorrect
spelling of bipedalism ("bipedialism") in your subject lines, even to
the point of changing it back after I've corrected it?
Tk> If you are talking, in some sort of round about way, about threat
Tk> displays, I realize of course that SOME animals exhibit threat displays
Tk> when cornered by a predator. By "our close relatives" I assume you mean
Tk> chimps and gorrillas, but they are not currently under a lot of
Tk> predation except from man. So they exhibit very little predatoral
Tk> threat displays. I think you are mainly talking about baboons which
Tk> exhibit threat displays as part of a defense, but this is also because
Tk> they are primarily savanna creatures which do not have the luxury of
Tk> running to a tree every time danger is encountered.
You are, of course, incorrect. In the post(s) I referred to, I talked
about chimpanzees, not baboons, and the way they react to predators.
You are again incorrect when you state that chimpanzees are not under
pressure from non-human predators.
Tk> The fact is that "Active young men will normally lose over 8 litres
Tk> of
Tk> water during a day when the desert temperature at midday is above
Tk> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of
Tk> water
Tk> in an hour of normal walking in a hot day in the desert."
Tk> >
JM> >First of all, who the hell ever said that australopithecines *ever* set
JM> >foot in the desert (besides you)?
Tk> Gee.. I didn't realize I said "Australopithecines set foot in the
Tk> desert". Thank you for explaining to me what I said.
Tk> I was mearly using a quote I had found about water consumption to
Tk> illustrate a point that hominids, when compared to other savanna
Tk> creatures, do not conserve water very well.
You gave a quote about how much water can be lost by active humans in
the desert, which has nothing whatsoever to do with australopithecines
unless they were in the desert. So your quote has nothing whatsoever to
do with the subject at hand. (Question: How much water would, say, a
wildebeest use in "an hour of walking in a hot day in the desert"?
Answer: who cares? the desert has nothing to do with its actual habitat.)
Tk> You can use all the quotes on water consumption you want and I promise
Tk> you I can find quotes that will contradict you.
Please do. Please also make sure that these quotes have something to do
with the actual habitat and level of activity that is relevant for
austrolopithecines. That would be a hot, wooded savannah mosaic
environment and creatures that act as chimps, gorillas, and indeed
virtually all animals do in that environment: moving about sporadically
rather than steadily, and resting in the readily available shade during
the hottest parts of the day. I'm afraid this leaves out quotes about
marathon running and walking through the desert.
Tk> I did however noticed
Tk> that the first part of this reference was an "estimate". I think that
Tk> the "estimated total daytime drinking requirements" by this author was a
Tk> very poor estimate.
Peter Wheeler's articles are readily available, and his research
techniques are stated in them. Feel free to counter his research with a
critique of his methods. Otherwise, "I think that [this] was a very
poor estimate" is simply a statement without basis, from someone who not
only hasn't read the work, but who doesn't seem to understand how
walking in the desert differs from foraging and resting in a wooded
savannah mosaic environment.
Here, to help you in your critique, are the years, volume numbers, and
page numbers for Peter Wheeler's articles in *Journal of Human
Evolution*: 1984, vol 13:91-98; 1985, vol 14:23-28; 1990, vol
19:321-322; 1991, vol 21:107-115; 1991, vol 21:117-136; 1992 vol
23:379-388; 1992, vol 23:351-362; 1993, vol 24:13-28; 1994, vol
26:339-350.
Tk> I don't think there is really any question, no matter what quote you
Tk> come up with, that the susceptibility of early hominids to dehydration
Tk> was probably pretty high. If you look at any other creature on the
Tk> savanna, the ways in which they conserve water resources are far
Tk> superior to the human/pre-human model. Their body temperatures are
Tk> generally higher, they allow their internal body temperatures to rise in
Tk> response to heat and they don't sweat, they pant. Sweating may be an
Tk> efficient cooling mechanism for humans, but it is not an effective way
Tk> to stay cool unless there is access to plenty of water to re-hydrate the
Tk> body. I really don't think there is any argument about this.
And yet they *were* there; oh, not in the treeless and waterless
savannah that you imagine, but in the actual savannah environment that
existed in reality. And they were there for millions and millions of
years, which fact even the AAH accepts. So it is obvious that they
could and in fact did live and indeed thrive there.
Tk> >Si> to the conclusion that we must have evolved in a safe, shady, semi-
Tk> >Si> aquatic environment.
Tk> >Si> Troy Kelley
Tk> >
Tk> "Shady" at the seashore? You've *never* been to the beach?
Tk> "You've *never* been to the beach?" - Now theres a good, well thought
Tk> out, non-antagonistic question.
Tk> And to use one of your previous quotes - "Who the hell said anything
Tk> about a seashore?"
Hardy and Morgan, the principle architects of the AAH.
Tk> I don't think DRINKING sea water for re-hydration
Tk> would be a very effective way to say alive on the Africa savanna.
I would agree, but of course, there is no need to go around drinking sea
water in a wooded savannah environment, as opposed to the putatively
aquatic ancestor.
JM> Safe? From
JM> crocs and sharks we can't even see approaching? And which don't
JM> respond
JM> to human and chimpanzee threat displays (as big cats and other land
JM> predators do)?
Tk> And besides that, I don't think crocodiles like salt water, in fact, I
Tk> know that they don't live in salt water.
"It's not what he doesn't know that scares me, but all the things he
knows for sure that just ain't so." You invite scathingly critical
replies when you post nonsense when you could easily check your facts
first. The estuarian crocodile, as has already been pointed out to you,
inhabits salt-water (that's why it's often called the "salt-water
crocodile") and is the largest, and some say the most vicious, of the
crocodiles. Since not only is this information easy to find in any
library, but has in fact been posted in the AAH threads here and
elsewhere several times, one is lead to the feeling that you are not
merely ignorant of many things you profess to know, but in fact are
*willfully* ignorant. You *could* change that, you know.
Tk> Haven't you ever been to the beach?
Tk> Troy Kelley
Yes, I have, but didn't swim or wade, due to the prevalence of shark
attacks in the area.
Jim Moore (j#d#.mo...@canrem.com)
* Q-Blue 1.0 *
Troy Kelley
Date: Sat, 10 Jun 95 14:36:00 -0500
In article <60.1715.72...@canrem.com> J. Moore,
j#d#.mo...@canrem.com
writes:
>Tk> If you are talking, in some sort of round about way, about threat
>Tk> displays, I realize of course that SOME animals exhibit threat
displays
>Tk> when cornered by a predator. By "our close relatives" I assume you
mean
>Tk> chimps and gorrillas, but they are not currently under a lot of
>Tk> predation except from man. So they exhibit very little predatoral
>Tk> threat displays. I think you are mainly talking about baboons which
>Tk> exhibit threat displays as part of a defense, but this is also
because
>Tk> they are primarily savanna creatures which do not have the luxury of
>Tk> running to a tree every time danger is encountered.
>
>You are, of course, incorrect. In the post(s) I referred to, I talked
>about chimpanzees, not baboons, and the way they react to predators.
>You are again incorrect when you state that chimpanzees are not under
>pressure from non-human predators.
The fact is, chimpazees have very few natural (non-human) predators in
the wild
and will live to a ripe old age in the wild.
>
>Tk> The fact is that "Active young men will normally lose over 8 litres
>Tk> of
>Tk> water during a day when the desert temperature at midday is above
>Tk> 40 C." "A man weighing 90 kilograms can sweat over 2 liters of
>Tk> water
>Tk> in an hour of normal walking in a hot day in the desert."
>Tk> >
>JM> >First of all, who the hell ever said that australopithecines *ever*
set
>JM> >foot in the desert (besides you)?
>
>Tk> Gee.. I didn't realize I said "Australopithecines set foot in the
>Tk> desert". Thank you for explaining to me what I said.
>
>Tk> I was mearly using a quote I had found about water consumption to
>Tk> illustrate a point that hominids, when compared to other savanna
>Tk> creatures, do not conserve water very well.
>
>You gave a quote about how much water can be lost by active humans in
>the desert, which has nothing whatsoever to do with australopithecines
>unless they were in the desert. So your quote has nothing whatsoever to
>do with the subject at hand. (Question: How much water would, say, a
>wildebeest use in "an hour of walking in a hot day in the desert"?
>Answer: who cares? the desert has nothing to do with its actual habitat.)
The point was still that hominids do not conserve water very well, IN
ANY KIND OF HABITAT. I understand that they do not live in the desert
but I was merely pointing to their unusually high water consumption rates.
Did I not make that clear?
>
>Tk> You can use all the quotes on water consumption you want and I
promise
>Tk> you I can find quotes that will contradict you.
>
>Please do. Please also make sure that these quotes have something to do
>with the actual habitat and level of activity that is relevant for
>austrolopithecines. That would be a hot, wooded savannah mosaic
>environment and creatures that act as chimps, gorillas, and indeed
>virtually all animals do in that environment: moving about sporadically
>rather than steadily, and resting in the readily available shade during
>the hottest parts of the day. I'm afraid this leaves out quotes about
>marathon running and walking through the desert.
>
>Tk> I did however noticed
>Tk> that the first part of this reference was an "estimate". I think
that
>Tk> the "estimated total daytime drinking requirements" by this author
was a
>Tk> very poor estimate.
>
>Peter Wheeler's articles are readily available, and his research
>techniques are stated in them. Feel free to counter his research with a
>critique of his methods. Otherwise, "I think that [this] was a very
>poor estimate" is simply a statement without basis, from someone who not
>only hasn't read the work, but who doesn't seem to understand how
>walking in the desert differs from foraging and resting in a wooded
>savannah mosaic environment.
If you really think I don't understand "how walking in the desert
differs from foraging and resting in a wooded savannah mosaic environment"
then I don't think you understood the point I was trying to make at all.
Yes, they thrived in an environment that had the necessary aquatic
resources in order to replenish any fluids lost during the hot day.
I think you are still missing the point here. The AAH argument is that if
hominids
evolved EXCLUSIVELY in a savanna environment, then why don't they
conserve water
resources as well as other savanna creatures?
>
>Tk> >Si> to the conclusion that we must have evolved in a safe, shady,
semi-
>Tk> >Si> aquatic environment.
>Tk> >Si> Troy Kelley
>Tk> >
>Tk> "Shady" at the seashore? You've *never* been to the beach?
>
>Tk> "You've *never* been to the beach?" - Now theres a good, well thought
>Tk> out, non-antagonistic question.
>
>Tk> And to use one of your previous quotes - "Who the hell said anything
>Tk> about a seashore?"
>
>Hardy and Morgan, the principle architects of the AAH.
Yes, but I never said anything about the sea shore. Personnally, I think
most
of the aquatic phases took place in fresh water rivers, lakes and
streams. It
is possible that some swimming, diving, foraging did occur in the ocean,
but this
is not good drinking water, so there must have been fresh water nearby.
>Tk> I don't think DRINKING sea water for re-hydration
>Tk> would be a very effective way to say alive on the Africa savanna.
>
>I would agree, but of course, there is no need to go around drinking sea
>water in a wooded savannah environment, as opposed to the putatively
>aquatic ancestor.
>
>JM> Safe? From
>JM> crocs and sharks we can't even see approaching? And which don't
>JM> respond
>JM> to human and chimpanzee threat displays (as big cats and other land
>JM> predators do)?
>
>Tk> And besides that, I don't think crocodiles like salt water, in fact,
I
>Tk> know that they don't live in salt water.
>
>"It's not what he doesn't know that scares me, but all the things he
>knows for sure that just ain't so." You invite scathingly critical
>replies when you post nonsense when you could easily check your facts
>first. The estuarian crocodile, as has already been pointed out to you,
>inhabits salt-water (that's why it's often called the "salt-water
>crocodile") and is the largest, and some say the most vicious, of the
>crocodiles. Since not only is this information easy to find in any
>library, but has in fact been posted in the AAH threads here and
>elsewhere several times, one is lead to the feeling that you are not
>merely ignorant of many things you profess to know, but in fact are
>*willfully* ignorant. You *could* change that, you know.
The estuarian crocodile lives in ESTUARIES which are BRACKISH; or
mixtures of some
salt with but mostly fresh water. If these crocodiles are exposed to the
kinds of
salt levels found in the ocean for a long enough period of time, they
will die.
Besides, crocodiles living in salt water, even though you seem to latch
on to this
issue rather quickly, is not the real issue for this news group. I was
not
implying that an aquatic environment was free from predators. I was
merely
pointing out that given our many physical deficiencies, which I am not
going to
list again, we must have evolved in a relatively safe environment. We
may have
developed defensive strategies to help avoid crocodiles. And I have
stated in this
news group before, that I would imagine it would be easier to deal with
crocodiles
as a predator than it would be to deal with lions, or big cats on the
open plains.
The first reason is because crocodiles lay their eggs in shallow nests
around the
edges of their aquatic environment and do very little to defend these
nests.
These eggs would make a very good meal for early hominids and it would be
an
effective way to control the population of crocodiles as a whole. I
doubt if
early hominids would have any chance of making a meal out of lion cubs or
leopard
kittens. Secondly, crocodiles are dumb. They are much dumber than
lions, and I
would imagine that a defensive strategy could be developed to deal with
them after
some examination of their habits.
>
>Tk> Haven't you ever been to the beach?
>Tk> Troy Kelley
>
>Yes, I have, but didn't swim or wade, due to the prevalence of shark
>attacks in the area.
Shark attacks kill fewer people than lightning does each year. You should
have
gone in the water. BTW, did you drive to the beach? That is much more
dangerous
that swimming in the ocean as well.
>
>Jim Moore (j#d#.mo...@canrem.com)
>
Troy Kelley
Troy Kelley
Date: 13 Jun 1995 02:53:04 GMT
In article <3riuig$9...@pandora.sdsu.edu> Drew Talley,
tal...@sunstroke.sdsu.edu writes:
>As you point out below, none of this is terribly pivotal for the
>argument at hand. What is odd is your willingness to state
>with such certainty things which are simply not true, and which
>a nominal amount of investigating would have informed you.
>
>: Besides, crocodiles living in salt water, even though you seem to latch
>: on to this
>: issue rather quickly, is not the real issue for this news group. I was
>: not
>: implying that an aquatic environment was free from predators. I was
>: merely
>: pointing out that given our many physical deficiencies, which I am not
>: going to
>: list again, we must have evolved in a relatively safe environment. We
>: may have
>
>Drew
OK, OK.. Drew, Jim... you were right, I was wrong. Crocodiles can live
in water that containes various levels of salt. I made a mistake. I
shouldn't have said "I know crocodiles don't live in salt water", I made
a mistake.
I guess I should have typed, "you aren't likely to find crocodiles
swimming around in the open ocean with sharks" but I didn't. Or I should
have said, "you aren't likely to find crocodiles at the beach, but more
likely in rivers or streams." Or maybe I should have said "Crocodiles are
brackish animals and have varying tolerances to salt water".
Now... since this issue of crocodile tolerance to salt is out of the way,
can we please get back to the issue of AAT, or is that all but forgotten?
Troy Kelley
HARRY R. ERWIN
environment was fresh-water, rather than salt-water. Since the major
alternative (the wooded savanna ape) was also tied to water, there appears
to be a compromise available--an ape specialized for life in gallery
forests, with arboreal, terrestrial, and semi-aquatic components to its
substratum adaptation. Is there a way of testing this? Are there species
that people can identify with comparable adaptations? (I have a few in
mind, myself.)
--
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin
Drew Talley
: Yes, but I never said anything about the sea shore. Personnally, I think
: most
: of the aquatic phases took place in fresh water rivers, lakes and
: streams. It
: is possible that some swimming, diving, foraging did occur in the ocean,
: but this
: is not good drinking water, so there must have been fresh water nearby.
For example, an estuary?
[deletia]
: >
: >JM> Safe? From
: >JM> crocs and sharks we can't even see approaching? And which don't
: >JM> respond
: >JM> to human and chimpanzee threat displays (as big cats and other land
: >JM> predators do)?
: >
: >Tk> And besides that, I don't think crocodiles like salt water, in fact,
: I
: >Tk> know that they don't live in salt water.
: >
[existence of croc which swims in the ocean mentioned]
: The estuarian crocodile lives in ESTUARIES which are BRACKISH; or
: mixtures of some
: salt with but mostly fresh water. If these crocodiles are exposed to the
Okay, if I may enter in here again...while I know almost _nothing_
about anthropology, I find the lively debate here entertaining. On
the other hand, if your pronouncements about anthro are as informed
as those about crocs and estuaries, I think you'll have some trouble
defending the AAH.
First off, estuaries are indeed mixtures of salt and fresh water,
but to contend thaT they are "mostly fresh water" is simply wrong.
The salinity in an estuary changes both seasonally and tidally,
and can range from pure freshwater to pure saltwater depending
on depth, location, and phase of those temporal changes.
: kinds of
: salt levels found in the ocean for a long enough period of time, they
: will die.
Again, this is not true (depending on what you think qualifies as
a "long enough time". Certainly, as has been pointed out to you,
they can swim into the open ocean for miles...easily long enough to move
up the coast a bit and snack on an ape, where available.
As you point out below, none of this is terribly pivotal for the
argument at hand. What is odd is your willingness to state
with such certainty things which are simply not true, and which
a nominal amount of investigating would have informed you.
: Besides, crocodiles living in salt water, even though you seem to latch
: on to this
: issue rather quickly, is not the real issue for this news group. I was
: not
: implying that an aquatic environment was free from predators. I was
: merely
: pointing out that given our many physical deficiencies, which I am not
: going to
: list again, we must have evolved in a relatively safe environment. We
: may have
: >
: >Tk> Haven't you ever been to the beach?
: >Tk> Troy Kelley
: >
: >Yes, I have, but didn't swim or wade, due to the prevalence of shark
: >attacks in the area.
: Shark attacks kill fewer people than lightning does each year. You should
: have
: gone in the water. BTW, did you drive to the beach? That is much more
: dangerous
: that swimming in the ocean as well.
Drew
tal...@sunstroke.sdsu.edu
or
dta...@ucsd.edu
: >Jim Moore (j#d#.mo...@canrem.com)
: >
: Troy Kelley
J. Moore
JM> >pressure from non-human predators.
Tk> The fact is, chimpazees have very few natural (non-human) predators in
Tk> the wild and will live to a ripe old age in the wild.
Odd that you manage to suggest that, despite the fact that chimpanzees
manage to deal reasonably well with their potential predators, such as
lions and leopards, early hominids of similar size and brainpower would
be incapable of doing so.
JM> You gave a quote about how much water can be lost by active humans in
JM> the desert, which has nothing whatsoever to do with australopithecines
JM> unless they were in the desert. So your quote has nothing whatsoever
JM> to do with the subject at hand. (Question: How much water would, say, a
JM> wildebeest use in "an hour of walking in a hot day in the desert"?
JM> Answer: who cares? the desert has nothing to do with its actual
JM> habitat.)
Tk> The point was still that hominids do not conserve water very well, IN
Tk> ANY KIND OF HABITAT. I understand that they do not live in the desert
Tk> but I was merely pointing to their unusually high water consumption
Tk> rates. Did I not make that clear?
All that matters is whether or not they do *well enough*; that's how
evolution works. We see that in fact australopithecines did well enough
to survive in their environment for millions and millions of years. And
in fact even chimpanzees do well enough in relatively dry areas, similar
to those used by australopithecines.
Tk> If you really think I don't understand "how walking in the desert
Tk> differs from foraging and resting in a wooded savannah mosaic
Tk> environment" then I don't think you understood the point I was trying
Tk> to make at all.
Your point was, and is, irrelevant to the subject of australopithecine
adaption to their environment. Contrary to what you continually insist,
they just flat out worked in that environment; well enough to last there
for millions and millions of years.
Tk> > I don't think there is really any question, no matter what quote you
Tk> > come up with, that the susceptibility of early hominids to
Tk> > dehydration
Tk> > was probably pretty high. If you look at any other creature on the
Tk> > savanna, the ways in which they conserve water resources are far
Tk> > superior to the human/pre-human model. Their body temperatures are
Tk> > generally higher, they allow their internal body temperatures to
Tk> > rise in response to heat and they don't sweat, they pant.
Evolution works on what is there; it can't just build a whole new system
from scratch. Humans are primates, they evolved from primates, not from
antelopes, or pigs, or dogs. The fact that they use different physical
structures to accomplish similar ends compared to some other animals in
similar environments is not evidence that they didn't live there. In
fact, we know that they *did* live there, so whatever system they used
obviously worked well enough, regardless of whether or not other systems
worked "better". The "better" is in quotes because one problem with
using a physical adatation as a "solution to an environmental problem"
is that it almost inevitably reduces your options as a species. This
isn't a problem for a species that stays put in an environment that
changes slowly, but as it turns out for humans, it was yet another lucky
break in our evolutionary past that we didn't have such a gross
morphological adaptation to limit us.
JM> >And yet they *were* there; oh, not in the treeless and waterless
JM> >savannah that you imagine, but in the actual savannah environment that
JM> >existed in reality. And they were there for millions and millions of
JM> >years, which fact even the AAH accepts. So it is obvious that they
JM> >could and in fact did live and indeed thrive there.
Tk> Yes, they thrived in an environment that had the necessary aquatic
Tk> resources in order to replenish any fluids lost during the hot day.
Tk> I think you are still missing the point here. The AAH argument is that
Tk> if hominids
Tk> evolved EXCLUSIVELY in a savanna environment, then why don't they
Tk> conserve water
Tk> resources as well as other savanna creatures?
As I pointed out above, you can't just evolve whatever "takes your
fancy"; evolution works with what is there in the organism. So no, we
didn't survive there like antelopes do, or like warthogs, or by
burrowing and coming out at night, or by digging into the ground and
popping out every few months after the rains fall, or by any of the many
*different* ways that animals survived and still survive in that
environment -- we did it our way. (Everybody sing!)
Tk> Yes, but I never said anything about the sea shore. Personnally, I think
Tk> most
Tk> of the aquatic phases took place in fresh water rivers, lakes and
Tk> streams.
Tk> The estuarian crocodile lives in ESTUARIES which are BRACKISH; or
Tk> mixtures of some
Tk> salt with but mostly fresh water. If these crocodiles are exposed to
Tk> the kinds of
Tk> salt levels found in the ocean for a long enough period of time, they
Tk> will die.
As has been pointed out to you, both recently and several times
previously, you are incorrect.
Tk> Besides, crocodiles living in salt water, even though you seem to latch
Tk> on to this
Tk> issue rather quickly, is not the real issue for this news group.
I bring it up because a basic tenet of the AAH has been that "the
savannah" is full of dangerous predators, and the oceans (swamps,
streams, rivers, lakes, etc.) are not. The fact is that not only are
those waters full of dangerous predators, the predators there are also
demonstrably not as easy to see and do not respond to bluff and threats
as the major land-based predators [of large primates] demonstrably do.
Tk> I was not
Tk> implying that an aquatic environment was free from predators. I was
Tk> merely
Tk> pointing out that given our many physical deficiencies, which I am not
Tk> going to
Tk> list again, we must have evolved in a relatively safe environment. We
Tk> may have
Tk> developed defensive strategies to help avoid crocodiles. And I have
Tk> stated in this
Tk> news group before, that I would imagine it would be easier to deal with
Tk> crocodiles
Tk> as a predator than it would be to deal with lions, or big cats on the
Tk> open plains.
And here you make exactly that bogus point, contrary to fact.
Tk> The first reason is because crocodiles lay their eggs in shallow nests
Tk> around the
Tk> edges of their aquatic environment and do very little to defend these
Tk> nests.
Tk> These eggs would make a very good meal for early hominids and it would
Tk> be an
Tk> effective way to control the population of crocodiles as a whole.
The fact that crocodiles thrived in massive numbers along every African
waterway until extremely recently convincingly demonstrates that their
population wasn't well enough controlled to keep them from being a
constant danger to anything of reasonable size which enters the water
(fresh or salt).
Tk> I doubt if early hominids would have any chance of making a meal
Tk> out of lion cubs or leopard kittens.
Judging from the chimp actions at the leopard den at Mahale, I don't
think they would make a meal of them either. The chimps didn't eat the
leopard cub, they just killed it.
Tk> Secondly, crocodiles are dumb. They are much dumber than
Tk> lions, and I
Tk> would imagine that a defensive strategy could be developed to deal with
Tk> them after some examination of their habits.
Sure: stay out of the water. Quite effective, and easy to figure out
too.
It's their stupidity that makes them so hard to deal with. They just
don't respond well to threats, as the relatively smart mammalian
predators do.
Tk> >Tk> Haven't you ever been to the beach?
Tk> >Tk> Troy Kelley
JM> >Yes, I have, but didn't swim or wade, due to the prevalence of shark
JM> >attacks in the area.
Tk> Shark attacks kill fewer people than lightning does each year. You
Tk> should have
Tk> gone in the water. BTW, did you drive to the beach? That is much more
Tk> dangerous that swimming in the ocean as well.
Tk> Troy Kelley
Perhaps if *you're* driving. When driving, as with land-based mammalian
predators, you have some control over the situation (well, *I* do, anyway).
If you keep your wits about you, you can usually see trouble coming and
therefore take effective steps to avoid it. With sharks as with
crocodiles, your chances of seeing the trouble coming are greatly
reduced, and your chances of doing something about it once it arrives
are virtually nil.
J. Moore
He> environment was fresh-water, rather than salt-water. Since the major
He> alternative (the wooded savanna ape) was also tied to water, there
He> appears to be a compromise available--an ape specialized for life in
He> gallery forests, with arboreal, terrestrial, and semi-aquatic components
He> to its substratum adaptation. Is there a way of testing this? Are there
He> species that people can identify with comparable adaptations? (I have a
He> few in mind, myself.)
He> Harry Erwin
Some gorillas, various macaques and the proboscis monkey spend
varying amounts of time in all those places, but show none of the
supposed AAH adatations. They utilise common ape and monkey locomotor
behavior (a combination of quadrapedalism, brachiation, and bipedalism)
in each of these places. All are overwhelmingly quadrapedal on the
ground and in the water, despite claims by some AAH proponents that they
inevitably effect bipdal posture when in the water.
Various environments have been suggested by different AAH proponents;
all state that a major reason that these water environments were
necessary for the evolution of bipedalism is to help support the body
weight of the animal. Note that this necessarily means that the animal
must be well over waist deep in the water during much of the time that
it isn't sitting or lying. Knee-deep water isn't going to help support
body weight. Another major reason used is the claim that this
chest-deep water environment is much safer than being out in a
relatively open area where you have a chance to spot predators, hence
the other post(s) on the subject of predators.
J. Moore
Tk> >with such certainty things which are simply not true, and which
Tk> >a nominal amount of investigating would have informed you.
Tk> >
Tk> OK, OK.. Drew, Jim... you were right, I was wrong. Crocodiles can live
Tk> in water that containes various levels of salt. I made a mistake. I
Tk> shouldn't have said "I know crocodiles don't live in salt water", I made
Tk> a mistake.
Tk> I guess I should have typed, "you aren't likely to find crocodiles
Tk> swimming around in the open ocean with sharks" but I didn't. Or I
Tk> should have said, "you aren't likely to find crocodiles at the beach,
Tk> but more likely in rivers or streams."
If you had typed any of those things, you would also have been wrong.
Why not stick to writing what you know (I know, your posts would be too
short ;-), or, better yet, actually do some research before you make
wild statements, and actually look at both sides of an argument and try,
just try, to learn something along the way.
Tk> Now... since this issue of crocodile tolerance to salt is out of the
Tk> way, can we please get back to the issue of AAT, or is that all but
Tk> forgotten?
Tk> Troy Kelley
That depends, are you going to try and learn from posts, and perhaps do
some reading other than AAH supporters? If you aren't, you're doomed to
having people jump on your misstatements and misunderstandings just like
they did this time.
Cameron Laird
HARRY R. ERWIN <her...@osf1.gmu.edu> wrote:
>A clarification of at least one person's version of the AAT is that the
>to be a compromise available--an ape specialized for life in gallery
>forests, with arboreal, terrestrial, and semi-aquatic components to its
>substratum adaptation. Is there a way of testing this? Are there species
>that people can identify with comparable adaptations? (I have a few in
>mind, myself.)
.
.
.
I have no answers to those questions, so I'll ask my own.
One of the raps on Elaine Morgan is that she doesn't submit to
peer review. I see that
Morgan, Elaine
1995 The Descent of the Child: Human Evolution
from a New Perspective. Oxford University
Press
is now available. I haven't had one in my hands, but Oxford
U Pr in the past certainly has been a place that exercises
editorial oversight as responsibly as any other scientific
publisher. I'm curious to learn what the new perspective is.
What I really want: I think Oxf U Pr ought to send review
copies to Danny and Phil, and then we'll all meet back here
in a month.
--
Cameron Laird http://starbase.neosoft.com/~claird/home.html
cla...@Neosoft.com +1 713 267 7966
cla...@litwin.com +1 713 996 8546
Xiaoguang Zhang ~{UEO~9b~}
showed the amazing skills and coordination of new born infants under
water. It would be hard to convince me that these skills were simply
reflexes developed on land, especially the reflex of hoding breath.
Then it hit me. Is it possible, that at one point our ancestors were
living in a swamp, rather than savanna, where there was waist-high
water? This would probably force bipedalism, since anyone trying to
walk with hands would have his nose under water. Swimming might not
have been a viable alternative, since this period was probably too
short for an efficient swimmer to develop (there might be better
reasons such as food source, etc.). However, think about the infants
that were born in the water. They must know how to swim! They probably
clung to their mothers most of the time, but occasionly they might
fall into the water, and must be able to swim back to their mothers.
Is this idea crazy?
Troy Kelley
Date: Fri, 16 Jun 95 09:44:00 -0500
In article <60.1761.72...@canrem.com> J. Moore,
j#d#.mo...@canrem.com writes:
>Tk> Now... since this issue of crocodile tolerance to salt is out of the
>Tk> way, can we please get back to the issue of AAT, or is that all but
>Tk> forgotten?
>Tk> Troy Kelley
>
>That depends, are you going to try and learn from posts, and perhaps do
>some reading other than AAH supporters? If you aren't, you're doomed to
>having people jump on your misstatements and misunderstandings just like
>they did this time.
>
>Jim Moore (j#d#.mo...@canrem.com)
>
Jeeezzzee.. I try and be nice and conciliatory and I just get another
blast from your obnoxious, self-righteous crap.
>Tk> I guess I should have typed, "you aren't likely to find crocodiles
>Tk> swimming around in the open ocean with sharks" but I didn't. Or I
>Tk> should have said, "you aren't likely to find crocodiles at the beach,
>Tk> but more likely in rivers or streams."
>
>If you had typed any of those things, you would also have been wrong.
OK, Jim, now it is your turn to do a little reserch. So PLEASE do tell
me your reference that says "You are very likely to find crocodiles
swimming around in the open ocean with sharks" and show me how I was
"wrong". I am eagerly awaiting your reply, because I just really love
when you prove to everyone your expansive knowledge on all matters of
aquatic animal behaviour.
If you do not post any references that say that crocodiles "are likely
to be found swimming around in the open ocean with sharks" I will assume
that I was right and you were wrong. BTW, I mean crocodiles in GENERAL,
not one or two species that is swimming across a oceanic area to a
different habitat. Also, notice I did say OPEN ocean, this means far
away from the shorelines or costal areas, in otherwords in the MIDDLE of
the ocean.
Just so there is no confusion as to how you are going to show me "if [I]
had typed any of those things, [I] would also have been wrong".
BTW, I would like to formally apologize to this news group for wasting
bandwith on crocodile habitat, but I feel this is getting personnel and I
must defend myself from blatantly obnoxious criticism.
Troy Kelley
J. Moore
Tk> >Tk> forgotten?
Tk> >Tk> Troy Kelley
Tk> >
JM> That depends, are you going to try and learn from posts, and perhaps do
JM> some reading other than AAH supporters? If you aren't, you're doomed
JM> to having people jump on your misstatements and misunderstandings just
JM> like they did this time.
JM>
JM> Jim Moore (j#d#.mo...@canrem.com)
Tk> Jeeezzzee.. I try and be nice and conciliatory and I just get another
Tk> blast from your obnoxious, self-righteous crap.
It's just stating a fact, Troy. If you don't get some sort of weird
kick out of people constantly pointing out that you're posting wrong
information (I'll assume your reaction shows that you don't get a kick
from it), you'll have to do some research first. Even when you made
your apologetic post, you added yet *more* incorrect information,
without any signs of having done any of the fairly easy research that
would've allowed you to post correct information. If you do this
continually, you're guaranteed to get replies like mine, or worse.
Tk> > I guess I should have typed, "you aren't likely to find crocodiles
Tk> > swimming around in the open ocean with sharks" but I didn't. Or I
Tk> > should have said, "you aren't likely to find crocodiles at the
Tk> > beach, but more likely in rivers or streams."
Tk> >
JM> If you had typed any of those things, you would also have been wrong.
Tk> OK, Jim, now it is your turn to do a little reserch. So PLEASE do tell
Tk> me your reference that says "You are very likely to find crocodiles
Tk> swimming around in the open ocean with sharks" and show me how I was
Tk> "wrong". I am eagerly awaiting your reply, because I just really love
Tk> when you prove to everyone your expansive knowledge on all matters of
Tk> aquatic animal behaviour.
Tk> If you do not post any references that say that crocodiles "are likely
Tk> to be found swimming around in the open ocean with sharks" I will assume
Tk> that I was right and you were wrong. BTW, I mean crocodiles in GENERAL,
Tk> not one or two species that is swimming across a oceanic area to a
Tk> different habitat. Also, notice I did say OPEN ocean, this means far
Tk> away from the shorelines or costal areas, in otherwords in the MIDDLE of
Tk> the ocean.
Why wouldn't just one species do? No, crocodiles "in general" do not
swim in the ocean, and I must point out that "open ocean" and "in the
middle of the ocean" are rather different (oceans are big). BTW, I
noticed you dropped your "at the beach" reference -- good idea. I
should apologise and say simply that, although Indopacific Crocodiles
can and do swim into the open ocean at some distance from land, this
isn't nearly as common as finding them "at the beach". Which,
incidentally, is where the putative aquatic hominid was to be found.
Tk> Just so there is no confusion as to how you are going to show me "if
Tk> [I] had typed any of those things, [I] would also have been wrong".
Tk> BTW, I would like to formally apologize to this news group for wasting
Tk> bandwith on crocodile habitat, but I feel this is getting personnel and
Tk> I must defend myself from blatantly obnoxious criticism.
Tk> Troy Kelley
Crocodile habitat is in fact crucial to discussions of the AAH, as any
account of human evolution must contend with how our ancestors coped
with dangerous predators, and I'll post on it shortly.
Jim Moore (j#d#.mo...@canrem.com)
* Q-Blue 2.0 *
Sir CPU
Date: Thu, 15 Jun 95 09:01:00 -0500
Message-ID: <60.1747.72...@canrem.com>
I would like to respond to some of your previous posts.
JM> >You are again incorrect when you state that chimpanzees are not under
JM> >pressure from non-human predators.
Tk> The fact is, chimpazees have very few natural (non-human) predators in
Tk> the wild and will live to a ripe old age in the wild.
-Odd that you manage to suggest that, despite the fact that chimpanzees
-manage to deal reasonably well with their potential predators, such as
-lions and leopards, early hominids of similar size and brainpower would
-be incapable of doing so.
Well, I think chimps have a better opportunity to climb trees in the
wooded environment which they live. I think that if early hominids were
out on the open savanna, as the savanna theory states, they would have
much less of a chance to escape from a predator, especially a lion, to a
tree.
JM> You gave a quote about how much water can be lost by active humans in
JM> the desert, which has nothing whatsoever to do with australopithecines
JM> unless they were in the desert. So your quote has nothing whatsoever
JM> to do with the subject at hand. (Question: How much water would, say,
a
JM> wildebeest use in "an hour of walking in a hot day in the desert"?
JM> Answer: who cares? the desert has nothing to do with its actual
JM> habitat.)
Tk> The point was still that hominids do not conserve water very well, IN
Tk> ANY KIND OF HABITAT. I understand that they do not live in the desert
Tk> but I was merely pointing to their unusually high water consumption
Tk> rates. Did I not make that clear?
-All that matters is whether or not they do *well enough*; that's how
-evolution works. We see that in fact australopithecines did well enough
-to survive in their environment for millions and millions of years. And
-in fact even chimpanzees do well enough in relatively dry areas, similar
-to those used by australopithecines.
The point is, however, if hominids were evolving on the savanna for the
millions of years that they were supposedly, how come their evolution
didn't bring them up to the level of other savanna creatures. It is that
simple. I mean, don't you find it the least bit odd that the human body
temperature of 98 degrees is more like that of a dolphin or a whale than
that of other savanna creatures? And don't you find it odd that we expend
a tremendous amount of energy and resouces to keep our body temperature
constant, again like aquatic creatures, instead of allowing our internal
body temperature to rise? Again, if we were on the savanna for the
millions of years as you say, and did not have an interviening period of
"aquatic-ness", instead evolving with the other savanna creatures, why
then did we not end up evolving the same way?
Tk> If you really think I don't understand "how walking in the desert
Tk> differs from foraging and resting in a wooded savannah mosaic
Tk> environment" then I don't think you understood the point I was trying
Tk> to make at all.
-Your point was, and is, irrelevant to the subject of australopithecine
-adaption to their environment. Contrary to what you continually insist,
-they just flat out worked in that environment; well enough to last there
-for millions and millions of years.
You point of "well they were there, on the savanna, and they mananged to
survive well enough to get us to were we are today"; I don't think is a
very good one. Sure we were there, but we ended up taking a different
evolutionary path from the majority of animals there, now the question is
why? If you want to say, "well we did, and we made it ok, and that is
that, fine". But as a scientist, don't the peculuarities of our
anotomical structures make you wonder what causes us to be that way? And
then look for a SIMPLE explaination to cover all aspects of our unusual
physical structures?
Tk> > I don't think there is really any question, no matter what quote you
Tk> > come up with, that the susceptibility of early hominids to
Tk> > dehydration
Tk> > was probably pretty high. If you look at any other creature on the
Tk> > savanna, the ways in which they conserve water resources are far
Tk> > superior to the human/pre-human model. Their body temperatures are
Tk> > generally higher, they allow their internal body temperatures to
Tk> > rise in response to heat and they don't sweat, they pant.
-Evolution works on what is there; it can't just build a whole new system
-from scratch.
I agree. And this is why I think you see the strange human configuration.
Because evolution worked on an aquatic ape that was suddenly living on the
african plains.
-As I pointed out above, you can't just evolve whatever "takes your
-fancy"; evolution works with what is there in the organism. So no, we
-didn't survive there like antelopes do, or like warthogs, or by
-burrowing and coming out at night, or by digging into the ground and
Again, I think you are supporting my claim again. Evolution worked with
what it had in the organism, and aquatic organism, and came up with some
unusual strategies to cope with life on the savanna.
This is not a good arguement to defend our evolution on the savanna. To
say we were there, and we made due with our evolutionary circumstances,
does not cover the unusual aspects of our evolution that separate us from
other savanna creatures. I think the AAT goes a long way to help explain
these peculuarities, even if I don't know enough about crocodile habitats.
Troy Kelley
David L Burkhead
Subject: Re: Bipedalism and other factors
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In article <3sabc8$s...@newsbf02.news.aol.com> sir...@aol.com (Sir CPU) writes:
[ 8< Chimpanzees and natural predators >8 ]
>
>-Odd that you manage to suggest that, despite the fact that chimpanzees
>-manage to deal reasonably well with their potential predators, such as
>-lions and leopards, early hominids of similar size and brainpower would
>-be incapable of doing so.
>
>Well, I think chimps have a better opportunity to climb trees in the
>wooded environment which they live. I think that if early hominids were
>out on the open savanna, as the savanna theory states, they would have
>much less of a chance to escape from a predator, especially a lion, to a
>tree.
Several things here. First, climbing trees is not a terribly
effective escape strategy from leopards (a more serious threat in
wooded environs than lions, which are savanna creatures). Leopards
climb quite well, and being lighter than the chimps, they can travel
onto any branch which will support a chimp's weight. But that's
really a side issue. Check how chimpanzees _actually deal_ with
leopards. The footage I have seen did _not_ involve the chimps
fleeing, at least not all of them. A group of them gathered to throw
sticks and stones at the leopard to drive it away.
Sigh. This point has been answered _repeatedly_. Evolution
works with what's at hand. Pre-humans did not have the same starting
point as other savanna creatures. Thus, to expect the same results is
fatuous nonsense. All that matters is if human survival mechanisms
worked _well enough_. They patently did since they _did_ survive for
millions of years on the savanna. This savanna period also happened
_after_ any postulated aquatic period, so your arguments about
"intervening period of "aquatic-ness" is totally empty. There's no
_time_ after the known savanna and later periods for this hypothetical
aquatic phase.
Why don't humans let their body temperature rise? My guess would
be because we don't have large snouts to keep the _brain_ cool (as do
other large savanna mammals) and so have to keep the entire body cool.
Why the "coincidence" of body temperature? Well, why not provide some
_data_ on that? Just what body temperatures are found in various
animals--woodland primates, savanna dwelling large mammals, aquatic
mammals. A vague, arm-wavey "more like aquatic animals" says nothing
of substance.
>
>Tk> If you really think I don't understand "how walking in the desert
>Tk> differs from foraging and resting in a wooded savannah mosaic
>Tk> environment" then I don't think you understood the point I was trying
>Tk> to make at all.
>
>-Your point was, and is, irrelevant to the subject of australopithecine
>-adaption to their environment. Contrary to what you continually insist,
>-they just flat out worked in that environment; well enough to last there
>-for millions and millions of years.
>
>You point of "well they were there, on the savanna, and they mananged to
>survive well enough to get us to were we are today"; I don't think is a
>very good one. Sure we were there, but we ended up taking a different
>evolutionary path from the majority of animals there, now the question is
>why? If you want to say, "well we did, and we made it ok, and that is
>that, fine". But as a scientist, don't the peculuarities of our
>anotomical structures make you wonder what causes us to be that way? And
>then look for a SIMPLE explaination to cover all aspects of our unusual
We "ended up taking a different evolutionary path" because we
started from a different point. As has been pointed out to you time
and again evolution works with the material at hand. (Okay, that's
anthropomorphising the process but it will work as a metaphor, I guess.)
>physical structures?
>
>Tk> > I don't think there is really any question, no matter what quote you
>Tk> > come up with, that the susceptibility of early hominids to
>Tk> > dehydration
>Tk> > was probably pretty high. If you look at any other creature on the
>Tk> > savanna, the ways in which they conserve water resources are far
>Tk> > superior to the human/pre-human model. Their body temperatures are
>Tk> > generally higher, they allow their internal body temperatures to
>Tk> > rise in response to heat and they don't sweat, they pant.
>
>-Evolution works on what is there; it can't just build a whole new system
>-from scratch.
>
>I agree. And this is why I think you see the strange human configuration.
>Because evolution worked on an aquatic ape that was suddenly living on the
>african plains.
Sorry, but "aquatic ape" is _still_ an unjustified assumption.
There is enough difference between woodland ape going savanna and
other savanna creatures that the different evolutionary path is
sufficiently explained that way. We have only assertions and
whole-cloth creations of hypotheses to claim otherwise.
>
>
>-As I pointed out above, you can't just evolve whatever "takes your
>-fancy"; evolution works with what is there in the organism. So no, we
>-didn't survive there like antelopes do, or like warthogs, or by
>-burrowing and coming out at night, or by digging into the ground and
>
>Again, I think you are supporting my claim again. Evolution worked with
>what it had in the organism, and aquatic organism, and came up with some
>unusual strategies to cope with life on the savanna.
No. He did nothing of the sort. "Different from other savanna
animals" (which leads to different solutions to survival problems)
does _not_ necessarily support _your_ particular claim.
> This is not a good arguement to defend our evolution on the savanna. To
>say we were there, and we made due with our evolutionary circumstances,
>does not cover the unusual aspects of our evolution that separate us from
>other savanna creatures. I think the AAT goes a long way to help explain
>these peculuarities, even if I don't know enough about crocodile habitats.
Not at all. AAH has some _serious_ problems. Main of these is
that it picks and chooses. There are enough properties of any living
thing that you can find cross correllations between different types.
Yet we have AAH making claims that are totally unsupported. For
instance, the claim is made that the aquatic phase is what led to our
becoming bipedal. Yet, when asked, its proponents cannot point to a
_single_ bipedal aquatic mammal. Not one. Where, then, did this
extraordinary claim come from? Whole cloth creation.
Likewise, the claim is made that an aquatic environment provided
a refuge from predators. This is nonsense. For one thing, the
weakness of humans in comparison with terrestrial predators (on a
purely physical level) is even worse for humans in water wrt _aquatic_
predators. I can (or could before my knees went to pot) run with a
speed 25-30% of the _fastest_ land predator. An olympic swimmer
would not make more than 5% of the fastest aquatic predators, and not
more than 10% of more "typical" predators. Then, in the water, it is more
difficult to see predators coming and avoid them. Likewise, it is more
difficult to band together to drive off a predator (as those chimps did).
Also, aquatic predators are _stupid_ and unwilling to be driven off by threat
displays (unlike land based mammals).
Plainly, the AAH doesn't hold water.
David L. Burkhead
r3d...@dax.cc.uakron.edu
d.bur...@genie.geis.com
--
Spacecub - The Artemis Project - Artemis Magazine
Box 831
Akron, OH 44309-0831
Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086
512-471-4206
adu...@mail.utexas.edu
I can't help but chime in here.
The fact that hominids are capable of maintaining a constant
temperature in a heat-stressing environment is evidence that we are well
adapted to that environment. There is often more than a single solution
to a given problem, and simply because we don't use the same mechanisms
that bovids and equids do to deal with a hot open ecosystem doesn't mean
we're not well-adapted to it.
In fact, it might be suggested that the hominid adaptation to
living in a heat-stressing environment is superior to that of other
critters that are out there. We can travel much longer distances in a
given time than most other savannah-dwelling critters, and there are many
accounts of humans "walking their prey to exhaustion" in the hot sun. A
bovid may be able to run fast for a short distance on a hot day, but it
can't run long. Ambush predation is one way to deal with this, and
"exhaustion predation" is another. Yes, there is a cost -- we can't
stray too far from the water hole (unless we use tools: canteen, gourd,
skin water-bag).
Another point -- there really isn't a lot of evidence that early
hominids were living strictly in a savannah environment. The faunal
remains associated w/ A. ramidus are definitely suggestive of a more
closed habitat, and much of the evidence for A. afarensis and A.
africanus also point to life in a mosaic habitat in which a number of
different microhabitats were available. A. boisei is found in
depositional environments that are indicative of wetter habitats than the
co-eval H. erectus. In fact, its not until the appearance of H. erectus
that we see good evidence for "good" adaptation to open habitats
(human-like intermembral index, 1.8 m stature, thin "equatorial" body
build).
And finally, a comment on leopards -- yes, they climb trees, but
they don't hunt in trees (their prey are almost exclusively terrestrial
animals).
Pat Dooley
>Some gorillas, various macaques and the proboscis monkey spend
>varying amounts of time in all those places, but show none of the
>supposed AAH adatations. They utilise common ape and monkey locomotor
>behavior (a combination of quadrapedalism, brachiation, and bipedalism)
>in each of these places. All are overwhelmingly quadrapedal on the
>ground and in the water, despite claims by some AAH proponents that they
>inevitably effect bipdal posture when in the water.
I didn't know gorillas spent much time in the water. A simple moat seems
to be enough to keep them confined at many zoos. Where did you get
that information?
I've seen plenty of information on Macaques wading into water. I've never
seen
anything about them going in to any depth on four legs. Where did you get
that information.
Proboscis monkeys are not often observed in the wild. I've not seen
anything
that suggests they are "overwhelming quadrupedal" in the water. Where did
you get that information?
>Various environments have been suggested by different AAH proponents;
>all state that a major reason that these water environments were
>necessary for the evolution of bipedalism is to help support the body
>weight of the animal. Note that this necessarily means that the animal
>must be well over waist deep in the water during much of the time that
>it isn't sitting or lying. Knee-deep water isn't going to help support
>body weight. Another major reason used is the claim that this
>chest-deep water environment is much safer than being out in a
>relatively open area where you have a chance to spot predators, hence
>the other post(s) on the subject of predators.
That "supporting weight" reason is a new one on me. Archimedes would
soon tell you that quadrupedal entry into the water would provide more
support.
What are the real advantages of wading compared to quadrupedalism?
1) Better vision across the surface of the water and back to land.
2) Lower energy usage compared to swimming.
3) Less disturbance of the water while looking for prey (.c.f. earlier
post on Bonobos wading in streams and catching small fish hiding
under floating leaves.)
Pat Dooley
Pat Dooley
of crocodiles, the predation of same upon AA, etc. etc.
1) At least one species of Crocodile found in Northern Australia is fully
salt
tolerant. They can, and do, take humans swimming in open water. (These
are big beasts, and fierce.)
2) Aboriginals make extensive use of water resources in the same areas
as salt water crocodiles without suffering from population destroying
predation. They know when and where it is safe to enter the water
and where not to. White toursists are the usual victims in the rare
cases
where a human is taken, usually because they ignore the signs telling
them to beware of crocodiles.
Primates in the chimpanzee class are usually good at figuring out where
danger lies, be it lions, leopards or crocodiles.
3) The argument that apes could not have adapted to an aquatic environment
because of sharks or crocodiles is bogus. Both predators have been
around
when many other mammal species made the transistion from land to
water.
The pioneers must have been pretty clumsy in the water during the
initial
stages of the transition, but they made it.
4) My understanding is that African crocodiles are not fully salt
tolerant. I also
believe that AAT proponents suggest the Sea of Afar as a likely site
for the
AA to evolve. Once this Sea was separated from the Indian Ocean/Red
Sea, it slowly evaporated over the course of a few milion years, just
as the
Red Sea is now doing. That implies increasing salinity and less
friendly
environment for crocodlies.
Pat Dooley
Pat Dooley
> The fact that hominids are capable of maintaining a constant
>temperature in a heat-stressing environment is evidence that we are well
>adapted to that environment. There is often more than a single solution
>to a given problem, and simply because we don't use the same mechanisms
>that bovids and equids do to deal with a hot open ecosystem doesn't mean
>we're not well-adapted to it.
> In fact, it might be suggested that the hominid adaptation to
>living in a heat-stressing environment is superior to that of other
>critters that are out there. We can travel much longer distances in a
>given time than most other savannah-dwelling critters, and there are many
>accounts of humans "walking their prey to exhaustion" in the hot sun. A
>bovid may be able to run fast for a short distance on a hot day, but it
>can't run long. Ambush predation is one way to deal with this, and
>"exhaustion predation" is another. Yes, there is a cost -- we can't
>stray too far from the water hole (unless we use tools: canteen, gourd,
>skin water-bag).
The pack hunters, such as the wild dog and hyena, fill the "exhaustion
predation" niche. Lions fill the ambush niche, to an extent. Was there
room for a 10 mph weaponless bipedal ape to go pack hunting on the
savannah? Doesn't compute for me.
The problem is that the range depends on the ability to carry water. That
requires a level of tool building sophistication that was not available
until
H. Erectus arrived on the scene; an event post dating the evolution of
bipedalism.
> Another point -- there really isn't a lot of evidence that early
>hominids were living strictly in a savannah environment. The faunal
>remains associated w/ A. ramidus are definitely suggestive of a more
>closed habitat, and much of the evidence for A. afarensis and A.
>africanus also point to life in a mosaic habitat in which a number of
>different microhabitats were available. A. boisei is found in
>depositional environments that are indicative of wetter habitats than the
>co-eval H. erectus. In fact, its not until the appearance of H. erectus
>that we see good evidence for "good" adaptation to open habitats
>(human-like intermembral index, 1.8 m stature, thin "equatorial" body
>build).
Which leads back to the $64k question. If bipedalism wasn't a savannah
adaptation, what was it?
Arboreal? The arms would be more orang like, and the legs much shorter.
Display? No sign of sexual dimorphism.
Temperature Regulation? But bipedalism didn't evolve on the savannah.
Speed? A new-born Gnu can out-run a mature human. You need a great 800m
time to survive on the savannah.
Tool carrying? Bipedalism predates tools.
Food gathering? Lots of problems with disadvantageous intermediate forms.
Wading & Swimming? Crazy notion, but it fits with some other oddities.
> And finally, a comment on leopards -- yes, they climb trees, but
>they don't hunt in trees (their prey are almost exclusively terrestrial
>animals).
But they often hunt from trees. The Tatung boy was, apparently, an early
victim.
Pat Dooley
Pat Dooley
>showed the amazing skills and coordination of new born infants under
>water. It would be hard to convince me that these skills were simply
>reflexes developed on land, especially the reflex of hoding breath.
>Then it hit me. Is it possible, that at one point our ancestors were
l>iving in a swamp, rather than savanna, where there was waist-high
>water? This would probably force bipedalism, since anyone trying to
>walk with hands would have his nose under water. Swimming might not
>have been a viable alternative, since this period was probably too
>short for an efficient swimmer to develop (there might be better
>reasons such as food source, etc.). However, think about the infants
>that were born in the water. They must know how to swim! They probably
>clung to their mothers most of the time, but occasionly they might
>fall into the water, and must be able to swim back to their mothers.
>
>Is this idea crazy?
Not according to Sir Alistair Hardy, Desmond Morris and Elaine Morgan.
You should read Morgans books, especially, "The Scars of Evolution."
Pat Dooley
Nicholas Rosen
<adu...@mail.utexas.edu> says:
>
>In article <3snsv4$c...@newsbf02.news.aol.com> Pat Dooley,>Are you nuts? Most body weight reconstructions indicate male A.
>afarensis were about twice as large as females. The same was probably
>true of all other australopithecine species as well, and possibly even
>earliest Homo (depending on how we slice up the habiline group).
What I think Pat meant is that there is no sign of sexual dimorphism
in bipedalism. Males were neither more nor less bipedal than females
of the same species.
>>> And finally, a comment on leopards -- yes, they climb trees, but
>>>they don't hunt in trees (their prey are almost exclusively terrestrial
>>>animals).
>>
>>But they often hunt from trees. The Tatung boy was, apparently, an early
>>victim.
>
>I assume you mean Taung? The fact that leopards hunt from trees would
>certainly encourage a pre-hominid to stay IN a tree.
I'm not so certain. Leopards may normally hunt FROM trees, but if a
creature on the leopard diet climbs a tree, will the leopard decline
the opportunity to eat it because that isn't the way a leopard
usually hunts?
Nicholas Rosen
Standard disclaimers apply.
J. Moore
JM> >varying amounts of time in all those places, but show none of the
JM> >supposed AAH adatations. They utilise common ape and monkey locomotor
JM> >behavior (a combination of quadrapedalism, brachiation, and bipedalism)
JM> >in each of these places. All are overwhelmingly quadrapedal on the
JM> >ground and in the water, despite claims by some AAH proponents that
JM> >they inevitably effect bipdal posture when in the water.
Pa> I didn't know gorillas spent much time in the water. A simple moat seems
Pa> to be enough to keep them confined at many zoos. Where did you get that
Pa> information?
"Much time"? You certainly have a knack for reading things into pharses
like "varying time" that just aren't there. Gorillas in the Congo and
Zaire sometimes forage in swampy clearings, where they effect typical
gorilla locomotion and feeding behavior. Sabater Pi reported this
around 1975, and there was even a Nature show on TV a couple of years
back that showed this behavior.
Pa> I've seen plenty of information on Macaques wading into water. I've
Pa> never seen
Pa> anything about them going in to any depth on four legs. Where did you
Pa> get that information.
Unless they are carrying things in both hands (or begging for food from
humans), they are quadrapedal unless the water would be over their heads.
Note that these examples of occasional bipedal behavior in shallow water
are identical to how they effect bipedal behavior on dry land, and so
offer no evidence for the contention of what I clearly said were:
JM> >claims by some AAH proponents that
JM> >they inevitably effect bipdal posture when in the water.
Pa> Proboscis monkeys are not often observed in the wild. I've not seen
Pa> anything
Pa> that suggests they are "overwhelming quadrupedal" in the water. Where
Pa> did you get that information?
You *could* try reading some books. But then you're apparently not even
reading the writings *by* AAT supporters. To whit:
JM> >Various environments have been suggested by different AAH proponents;
JM> >all state that a major reason that these water environments were
JM> >necessary for the evolution of bipedalism is to help support the body
JM> >weight of the animal. Note that this necessarily means that the animal
JM> >must be well over waist deep in the water during much of the time that
JM> >it isn't sitting or lying. Knee-deep water isn't going to help support
JM> >body weight. Another major reason used is the claim that this
JM> >chest-deep water environment is much safer than being out in a
JM> >relatively open area where you have a chance to spot predators, hence
JM> >the other post(s) on the subject of predators.
Pa> That "supporting weight" reason is a new one on me.
This a new one on me; an AAT supporter who hasn't even read the works of
the AAT proponents!
Pa> Archimedes would soon tell you that quadrupedal entry into the
Pa> water would provide more support.
I'm not gonna wait for Archimedes to rise form the dead and tell me
that; I've known it for years. The problem is, it's irrelevant.
Pa> What are the real advantages of wading compared to quadrupedalism?
This is a false dichotomy, or what Bateson would call a "confusion of
logical types"; "wading" and "quadrapedalism" are not, as you claim
here, mutually exclusive. Monkeys and apes which do go into water most
often do so quadrapedally.
Pa> 1) Better vision across the surface of the water and back to land.
If the water isn't over your head, you can see "back to land" just
fine with your head at the surface of the water. On land, however,
bipedalism for this purpose would be a huge advantage.
Pa> 2) Lower energy usage compared to swimming.
Refs, please. I've always found walking through water to be
energy-intensive, as water gives such much resistance. But please do
provide the references which contradict this impression.
Pa> 3) Less disturbance of the water while looking for prey (.c.f. earlier
Pa> post on Bonobos wading in streams and catching small fish hiding under
Pa> floating leaves.)
Pa> Pat Dooley
The AAT doesn't work if all you're claiming is that hominids
occasionally waded into ankle- or even knee-deep water; such behavior
requires no adaptations that are not those of a land-based primate.
So simple catching of fish in such shallow water provides no support for
the AAT's contentions that water allowed and even forced bipedalism
while land-based activities couldn't, and that our pattern of body hair
is an adaptation to intensive foraging and predator avoidance in water.
Perhaps you could explain how the AAT-hominids defended themselves
against fierce aquatic predators such as crocodiles and sharks.
Alex Duncan
>
>The pack hunters, such as the wild dog and hyena, fill the "exhaustion
>predation" niche. Lions fill the ambush niche, to an extent. Was there
>room for a 10 mph weaponless bipedal ape to go pack hunting on the
>savannah? Doesn't compute for me.
>
>The problem is that the range depends on the ability to carry water. That
>requires a level of tool building sophistication that was not available
>until
>H. Erectus arrived on the scene; an event post dating the evolution of
>bipedalism.
I may have entered this thread too late to fully understand the
arguments. Please clarify something: The AAT is offered as an
explanation for how hominids BECAME bipedal?
Yes, dogs and hyenas occupy the niche, but they don't necessarily
fill it. Hyenas are primarily nocturnal. That leaves the dogs out in
the day time, but does not mean that early humans couldn't also have
occupied that niche.
I wasn't suggesting that any hominids earlier than H. erectus
occupied this niche.
>
>> Another point -- there really isn't a lot of evidence that early
>>hominids were living strictly in a savannah environment. The faunal
>>remains associated w/ A. ramidus are definitely suggestive of a more
>>closed habitat, and much of the evidence for A. afarensis and A.
>>africanus also point to life in a mosaic habitat in which a number of
>>different microhabitats were available. A. boisei is found in
>>depositional environments that are indicative of wetter habitats than the
>>co-eval H. erectus. In fact, its not until the appearance of H. erectus
>>that we see good evidence for "good" adaptation to open habitats
>>(human-like intermembral index, 1.8 m stature, thin "equatorial" body
>>build).
>
>Which leads back to the $64k question. If bipedalism wasn't a savannah
>adaptation, what was it?
>
>Arboreal? The arms would be more orang like, and the legs much shorter.
How about this: hominids evolved from an ancestor that was so specialized
for an arboreal existence that its only effective mean of terrestrial
locomotion was bipedalism (see modern gibbons). In a fragmenting forest
environment, those pre-hominids that were most adept at moving from tree
to tree ON THE GROUND would have been selected for. An important thing
to note here is that this model doesn't suggest that pre-hominids adapted
bipedalism because living in open country was so wonderful. They did it
because they needed to cross open country from one patch of trees to the
next. As time went on, and aridification increased (e.g. terminal
Miocene climatic event) the patches between trees became progressively
larger and larger, selecting for more and more efficient bipeds.
Eventually the adaptation to crossing open ground became effective enough
that early hominids began other activities in open country (looking for
food, etc.).
>
>Display? No sign of sexual dimorphism.
Are you nuts? Most body weight reconstructions indicate male A.
afarensis were about twice as large as females. The same was probably
true of all other australopithecine species as well, and possibly even
earliest Homo (depending on how we slice up the habiline group).
>
>Temperature Regulation? But bipedalism didn't evolve on the savannah.
No, but it may have turned out to have the added benefit of helping temp.
regulation once hominids began routinely living in open country.
>
>Speed? A new-born Gnu can out-run a mature human. You need a great 800m
>time to survive on the savannah.
Or a complex social organization. A single hominid may have been easy
prey for a variety of savannah carnivores, but a group of cooperating
hominids would not.
>
>Tool carrying? Bipedalism predates tools.
Bipedalism predates tools that fossilize. Both humans and chimps use
tools, suggesting that this trait was present in the common ancestor of
humans and chimps, and thus, early hominids.
>
>Wading & Swimming? Crazy notion, but it fits with some other oddities.
I can think of no oddities that wading and swimming fit in with. Please
enlighten me. I'm not suggesting that early hominids didn't occasionally
enter the water, but to postulate an aquatic existence as the precursor
to all that is "hominid" flies in the face of all of the evidence I'm
aware of.
>
>> And finally, a comment on leopards -- yes, they climb trees, but
>>they don't hunt in trees (their prey are almost exclusively terrestrial
>>animals).
>
>But they often hunt from trees. The Tatung boy was, apparently, an early
>victim.
I assume you mean Taung? The fact that leopards hunt from trees would
certainly encourage a pre-hominid to stay IN a tree.
Alex Duncan
Phil Nicholls
>Jim Moore writes:
>>Some gorillas, various macaques and the proboscis monkey spend
>>varying amounts of time in all those places, but show none of the
>>supposed AAH adatations. They utilise common ape and monkey locomotor
>>behavior (a combination of quadrapedalism, brachiation, and bipedalism)
>>in each of these places. All are overwhelmingly quadrapedal on the
>>ground and in the water, despite claims by some AAH proponents that they
>>inevitably effect bipdal posture when in the water.
>I didn't know gorillas spent much time in the water. A simple moat seems
>to be enough to keep them confined at many zoos. Where did you get
>that information?
Lowland Gorillas wade into swamps on a regular basis. They are not as
well known as Mountain gorillas but a recent Nature special shows them
doing it rather clearly -- water up to their waste covering their
haunches.
>I've seen plenty of information on Macaques wading into water. I've never
>seen
>anything about them going in to any depth on four legs. Where did you get
>that information.
Macaques, in general, don't go into water so deep they have to stand
bipedally. Some do but the point is they show no special changes in
their muscluloskeletal systems.
>Proboscis monkeys are not often observed in the wild. I've not seen
>anything
>that suggests they are "overwhelming quadrupedal" in the water. Where did
>you get that information?
Kawabe, M. and Mano T. (1972) Ecology and Behavior of the wild
proboscis monkey (Nasalis larvatus, Wurmb) in Sabah, Malaysia,
PRIMATES 13:213-228.
>>Various environments have been suggested by different AAH proponents;
>>all state that a major reason that these water environments were
>>necessary for the evolution of bipedalism is to help support the body
>>weight of the animal. Note that this necessarily means that the animal
>>must be well over waist deep in the water during much of the time that
>>it isn't sitting or lying. Knee-deep water isn't going to help support
>>body weight. Another major reason used is the claim that this
>>chest-deep water environment is much safer than being out in a
>>relatively open area where you have a chance to spot predators, hence
>>the other post(s) on the subject of predators.
>That "supporting weight" reason is a new one on me. Archimedes would
>soon tell you that quadrupedal entry into the water would provide more
>support.
>What are the real advantages of wading compared to quadrupedalism?
>1) Better vision across the surface of the water and back to land.
Data?
>2) Lower energy usage compared to swimming.
Data?
>3) Less disturbance of the water while looking for prey (.c.f. earlier
>post on Bonobos wading in streams and catching small fish hiding
>under floating leaves.)
Bonobos wade into SHALLOW streams in ankle-deep water.
>Pat Dooley
==========================================================
Phil Nicholls "To ask a question you must first
pn...@globalone.net know most of the answer.
Semper Alouatta! - Robert Sheckley
Alex Duncan
ndr...@psuvm.psu.edu writes:
>>
>
>What I think Pat meant is that there is no sign of sexual dimorphism
>in bipedalism. Males were neither more nor less bipedal than females
>of the same species.
Are you sure about that? It may seem unlikely that males and females
would have different regimes of positional behaviors, but we do see such
things in modern gorillas and orangs. In both of these taxa, females are
more frequent arborealists than males.
See Stern & Susman (1983) Am. J. Phys. Anthrop. and Susman et al.
(1984) Folia Primatologia for a discussion of sexual dimorphism in
locomotor anatomy in A. afarensis. They suggest a greater frequency of
terrestrialism in males.
But really -- what do sexual differences in locomotion have to do
with display. I've never seen any hints that male and female chimps
differ significantly in locomotor behavior, but males display routinely
and more frequently than females.
>Leopards may normally hunt FROM trees, but if a
>creature on the leopard diet climbs a tree, will the leopard decline
>the opportunity to eat it because that isn't the way a leopard
>usually hunts?
I challenge you to find a single known instance of a leopard catching a
healthy baboon or chimpanzee IN A TREE. I'm not saying that it doesn't
happen, but it probably happens so rarely as to be insignificant.
Primates are much more adept in the arboreal substrate than leopards are.
Leopards are generally confined to the trunk and large proximal
branches. Primates (especially suspensory hominoids) are capable of
movement in the smaller distal branches where quadrupeds can't go.
A secondary and important point -- are we suggesting that primates
shouldn't climb trees because there are leopards there? This is getting
really ridiculous. You can count the number of terrestrial primate
species in Africa on the fingers of both hands. There are at least 50
species of primate in Africa (where the leopards are) that are almost
exclusively arboreal.
HARRY R. ERWIN
References: <3sabc8$s...@newsbf02.news.aol.com> <3snsv4$c...@newsbf02.news.aol.com> <3snsvk$d...@newsbf02.news.aol.com> <3snvuk$i...@geraldo.cc.utexas.edu>
Organization: George Mason University, Fairfax, Virginia, USA
Distribution: world
Subject: Re: Bipedalism and other factors
Newsgroups: sci.anthropology.paleo
References: <3sabc8$s...@newsbf02.news.aol.com> <3snsv4$c...@newsbf02.news.aol.com> <3snsvk$d...@newsbf02.news.aol.com> <3snvuk$i...@geraldo.cc.utexas.edu>
Organization: George Mason University, Fairfax, Virginia, USA
Distribution: world
Alex Duncan (adu...@mail.utexas.edu) wrote:
---trimmed---
: I may have entered this thread too late to fully understand the
: arguments. Please clarify something: The AAT is offered as an
: explanation for how hominids BECAME bipedal?
: Yes, dogs and hyenas occupy the niche, but they don't necessarily
: fill it. Hyenas are primarily nocturnal. That leaves the dogs out in
: the day time, but does not mean that early humans couldn't also have
: occupied that niche.
In fact, a biped would have partitioned this niche since it would have
been able to identify high-quality food sources at a longer distance than
the dogs.
: I wasn't suggesting that any hominids earlier than H. erectus
: occupied this niche.
My take as well.
: >
: >> Another point -- there really isn't a lot of evidence that early
: >>hominids were living strictly in a savannah environment. The faunal
: >>remains associated w/ A. ramidus are definitely suggestive of a more
: >>closed habitat, and much of the evidence for A. afarensis and A.
: >>africanus also point to life in a mosaic habitat in which a number of
: >>different microhabitats were available. A. boisei is found in
: >>depositional environments that are indicative of wetter habitats than the
: >>co-eval H. erectus. In fact, its not until the appearance of H. erectus
: >>that we see good evidence for "good" adaptation to open habitats
: >>(human-like intermembral index, 1.8 m stature, thin "equatorial" body
: >>build).
: >
: >Which leads back to the $64k question. If bipedalism wasn't a savannah
: >adaptation, what was it?
This reminds me of the current controversy about Acanthostega. It has
turned out that this relative/ancestor(?) of Icthyostega and the primitive
amphibians was obligately dependent on water--despite extremely primitive
limbs, it could not leave the water. Instead, it was apparently adapted to
predation in swamp environments where the use of fins to maintain one's
position would be detectable as pressure waves, but the use of hands and
feet would not.
Bipedalism could not have been a savannah adaptation because primitive
hominids couldn't make a living in the savannah. Too many other
adaptations had to be acquired first. It was an adaptation to something
else that preadapted the hominid (probably early Homo erectus) to move
into the savannah.
: >
: >Arboreal? The arms would be more orang like, and the legs much shorter.
: How about this: hominids evolved from an ancestor that was so specialized
: for an arboreal existence that its only effective mean of terrestrial
: locomotion was bipedalism (see modern gibbons). In a fragmenting forest
: environment, those pre-hominids that were most adept at moving from tree
: to tree ON THE GROUND would have been selected for. An important thing
: to note here is that this model doesn't suggest that pre-hominids adapted
: bipedalism because living in open country was so wonderful. They did it
: because they needed to cross open country from one patch of trees to the
: next. As time went on, and aridification increased (e.g. terminal
: Miocene climatic event) the patches between trees became progressively
: larger and larger, selecting for more and more efficient bipeds.
: Eventually the adaptation to crossing open ground became effective enough
: that early hominids began other activities in open country (looking for
: food, etc.).
I agree in general, but it sounds a little bit like Romer's scenario for
the emergence of the Icthyostegans onto the land. The ecological niche
occupied by these prehominids had to involve making a living in those
patchy forests. In deserts, bipeds have a longer search range than
quadrupeds of the same weight and lower energy costs than birds of the
same weight. The same would be the case (though less dominantly) in patchy
forests. I suspect the niche also involved climbing forest-edge trees to
the very top to get a good view of what was on the other side of the patch
of open land. I think Alex can work out the implications of this set of
selective forces.
: >
: >Display? No sign of sexual dimorphism.
: Are you nuts? Most body weight reconstructions indicate male A.
: afarensis were about twice as large as females. The same was probably
: true of all other australopithecine species as well, and possibly even
: earliest Homo (depending on how we slice up the habiline group).
Females 20-30 kg, males 40-50 seems to be the consensus, with some
workers estimating even lower weights (which are possible, since body
mass estimates depend on assumptions about the amount of muscle/fat/etc.
per unit volume). Weight dimorphism in the range 1.75-2.00 (i.e.,
extremely high).
---trimmed---
: >
: >Wading & Swimming? Crazy notion, but it fits with some other oddities.
: I can think of no oddities that wading and swimming fit in with. Please
: enlighten me. I'm not suggesting that early hominids didn't occasionally
: enter the water, but to postulate an aquatic existence as the precursor
: to all that is "hominid" flies in the face of all of the evidence I'm
: aware of.
It's easy to envision early hominids having some skill with water (i.e.,
behavioral adaptation), but without a great deal of skeletal adaptation in
that direction. Look at cats--tigers take to the water easily, while most
species avoid it. I suspect this can be tabled as having no strong
evidence in either direction. In any case, hominids probably did not
spend most of their time in the water. Not with limbs adapted to climbing
and bridging.
: >
: >> And finally, a comment on leopards -- yes, they climb trees, but
: >>they don't hunt in trees (their prey are almost exclusively terrestrial
: >>animals).
: >
: >But they often hunt from trees. The Tatung boy was, apparently, an early
: >victim.
: I assume you mean Taung? The fact that leopards hunt from trees would
: certainly encourage a pre-hominid to stay IN a tree.
Leopards use trees like I posit prehominids do--as bases for operations on
the ground. Given the relative weights and the arboreal quadrupedalism
seen in leopards, I suspect prehominids were fairly efficient at avoiding
a leopard if one came into their tree. Not only do their climbing and
bridging adaptations effectively double the space accessible to the
prehominids over equal-sized felids, but if the weight of the vulnerable
prehominids was sufficiently low relative to that of a leopard, they could
move out on branches or the main stem to regions of the tree that were
inaccessible to the leopard. Look at hoatzin behavior for some insight
into these issues.
Quick analysis: basic niche of leopards and prehominids was probably
similar, except that prehominids were more omnivorous. Since leopards are
quadrupedal, they need greater bodymass to be able to search at the same
rate on the ground, and are handicapped in their climbing to sighting
spots by that greater mass and their lack of grasping capability. Hence
prehominids had a greater search rate in a wooded savannah than any felid
(or canid). Group behavior that provided protection on the group against
carnivores would have allowed prehominids to maintain a larger population
in a patch of wooded savannah than felids could maintain. Canids could
maintain a larger population only if they were markedly less selective
than the prehominids in their feeding. That implies, by the way, that
leopards could not compete with prehominids except in areas of savannah
where the tree density was sufficiently low that leopards could exclude
prehominids from the available trees. You end up with four zones of
savannah:
1. treeless, where canids, birds, and large felids were dominant.
2. sparsely treed, where you found leopards,
3. moderately treed, where you found prehominids, and
4. heavily treed, where you found prechimps (since sighting range was not
the dominant selective force there).
Cheers --
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin (try a couple of times)
Barry Mennen
>The pack hunters, such as the wild dog and hyena, fill the
"exhaustion
>predation" niche. Lions fill the ambush niche, to an extent. Was there
>room for a 10 mph weaponless bipedal ape to go pack hunting on the
>savannah? Doesn't compute for me.
>time to survive on the savannah.
>
>
(tools)--wood doesn't fossilize too well--weaponless 10 mph
bipedalists?--weapons are what got us to where we are today--grow up!
Cheers
Barry
the ape man
Pat Dooley
>>I've seen plenty of information on Macaques wading into water. I've
never
>>seen
>>anything about them going in to any depth on four legs. Where did you
get
>>that information.
pn...@globalone.net (Phillip Nicholls) wrote:
>Macaques, in general, don't go into water so deep they have to stand
>bipedally. Some do but the point is they show no special changes in
>their muscluloskeletal systems.
Me:
And the wading is a relatively recent innovation for them. Evolution
doesn't
work that fast.
Me:
>>What are the real advantages of wading compared to quadrupedalism?
>>1) Better vision across the surface of the water and back to land.
Him:
>Data?
Me:
Try a little geometry, or trigonometry if common sense doesn't tell you
why.
Me:
>>2) Lower energy usage compared to swimming.
Him:
>Data?
Me:
How long can you tread water, compared to simply standing in it? How long
can you wade compared to swimming?
The energy efficiency of wading reduces as water depth increases. The
energy
cost of swimming is constant once the water is deep enough to sustain
swimming. For a bipedal ape, the point of equal efficiency is likely to
be between knee-deep and chest-deep. For a quadruped, the range within
which they can choose between swimming and wading is much more limited.
In circumstances in which wading is more efficient, whether that be
measured in terms of energy expenditure or food gathering efficiency,
primates often wade bipedally rather than swimming quadrupedally.
>>3) Less disturbance of the water while looking for prey (.c.f. earlier
>>post on Bonobos wading in streams and catching small fish hiding
>>under floating leaves.)
Him:
>Bonobos wade into SHALLOW streams in ankle-deep water.
Me:
It's a bit hard to tell from the reference you gave previously. However,
if the water was only ankle deep, there would have been no advantage
to the Bononbos wading bipedally to catch fish lurking amongst floating
leaves.
Pat Dooley
J. Moore
Pa> predation" niche. Lions fill the ambush niche, to an extent. Was there
Pa> room for a 10 mph weaponless bipedal ape to go pack hunting on the
Pa> savannah? Doesn't compute for me.
If you're going to talk about a transtional hominid, perhaps you could
try using some sort of example that actually has something to do with
how that hominid lived. Big game hunting seems to have begun no sooner
than at least 5-8 million years *after* the split from apes.
Pa> >different microhabitats were available. A. boisei is found in
Pa> >depositional environments that are indicative of wetter habitats than
Pa> the
Pa> >co-eval H. erectus. In fact, its not until the appearance of H.
Pa> erectus
Pa> >that we see good evidence for "good" adaptation to open habitats
Pa> >(human-like intermembral index, 1.8 m stature, thin "equatorial" body
Pa> >build).
Pa> Which leads back to the $64k question. If bipedalism wasn't a savannah
Pa> adaptation, what was it?
Why don't you just *try* reading some semi-current theory? Get rid of
your "treeless, waterless savannah" fixation and work with something
more accurate. You give some evidence above of knowing that the treeless,
waterless savannah you're using as a strawman versus the AAT is not
accurate.
Pa> Display? No sign of sexual dimorphism.
Perhaps you could try using complete enough sentences to make
intelligible thoughts as well.
Pa> Temperature Regulation? But bipedalism didn't evolve on the savannah.
You mean your "treeless, waterless savannah"?
Pa> Speed? A new-born Gnu can out-run a mature human. You need a great 800m
Pa> time to survive on the savannah.
You think all animals which don't live in the deep forest, who instead
live in semi-open savannah mosaic woodlands, can run as fast as
antelope?
Pa> Tool carrying? Bipedalism predates tools.
Actually unlikely; you are confusing "stone tools" with "tools". Again,
there's been *some* writing done on human evolution in the last 30 years.
Pa> Food gathering? Lots of problems with disadvantageous intermediate
Pa> forms.
The non-existent "law of disadvantageous intermediates" again. Give it
up, Pat; it doesn't exist.
Pa> > And finally, a comment on leopards -- yes, they climb trees, but
Pa> >they don't hunt in trees (their prey are almost exclusively terrestrial
Pa> >animals).
Pa> But they often hunt from trees. The Tatung boy was, apparently, an early
Pa> victim.
Pa> Pat Dooley
"Tatung"? I think that was those two-legged camel thingies Han Solo
rode in the second Star Wars movie. "Taung", on the other hand, was a
child, of unknown sex (where *do* you get your wacky ideas?), and you
also seem to mixing your sites willy-nilly (ie. mixing Taung and
Swartkrans here; Swartkrans is where you see possible signs of leopard
predation on australopithecines). Have you been checked for allergies
lately, like an allergy to facts? They don't seem to stick to you very
well.
At any rate, leopards, except possibly in deep forest, do not "hunt from
trees". Even a little study, or just casual watching of nature shows on
the tube, would tell you that leopards in African open woodlands and
savannah, hunt "from" the ground, and usually then carry their prey up
into trees to get away from obnoxious prey-stealing beasties, such as
hunting dogs and hyenas.
J. Moore
Pa> as salt water crocodiles without suffering from population destroying
Pa> predation. They know when and where it is safe to enter the water and
Pa> where not to. White toursists are the usual victims in the rare cases
Pa> where a human is taken, usually because they ignore the signs telling
Pa> them to beware of crocodiles.
It is certainly not unexpected that land-based hominids, such as *us*
(which includes Australian Aborigines), should not suffer "population
destroying predation" from water-living animals. Why would you even
think that was a possibility? What does the fact that modern land-based
people with sophisticated weaponry, such as knives and spears (and of
course guns now), do not suffer "population destroying predation" from
water-living animals have to do with a transitional water-living
population without these sophisticated weapons? Don't you even see the
ludicrous nature of using such an example (modern people with modern
weapons) as an argument about predation on a primitve hominid that
supposedly spends much of its time waist-deep or deeper in water?
Aborigines do not, as the AAT requires, spend at least half their waking
hours up to their waists, or above, in water.
Nevertheless, a quote from *Crocodiles and Alligators of the World*
(1991: 24): "The Australian Aborigines recognize differences in the risk
from various crocodile populations. In some areas, they maintain that
even Indo-Pacific crocodiles will not attack them, and they venture into
the water at these localities. Nevertheless, Aborigines do fall victim
to crocodiles, often when wading in water."
Pa> Primates in the chimpanzee class are usually good at figuring out
Pa> where danger lies, be it lions, leopards or crocodiles.
Agreed; that's why you see them holding their own against predation from
lions and leopards, and staying out of the water.
Pa> 3) The argument that apes could not have adapted to an aquatic
Pa> environment
Pa> because of sharks or crocodiles is bogus. Both predators have been
Pa> around
Pa> when many other mammal species made the transistion from land to water.
Pa> The pioneers must have been pretty clumsy in the water during the
Pa> initial stages of the transition, but they made it.
Pa> Pat Dooley
Okay, name them; name some tropical mammals that:
A) are about the size of these hominids (or smaller);
B) spend 4-8 hours a day in waist-deep or deeper water; and
C) reproduce as slowly as humans and chimps.
Please...name them. Please. I'm begging you.
Dewi Morgan
>Pa> The pack hunters, such as the wild dog and hyena, fill the "exhaustion
>Pa> predation" niche. Lions fill the ambush niche, to an extent. Was there
>Pa> room for a 10 mph weaponless bipedal ape to go pack hunting on the
>Pa> savannah? Doesn't compute for me.
>If you're going to talk about a transtional hominid, perhaps you could
>try using some sort of example that actually has something to do with
>how that hominid lived. Big game hunting seems to have begun no sooner
>than at least 5-8 million years *after* the split from apes.
So we hunted the little fluffy rodents? How could we? They are far too cute!
But, yes, I agree, big game hunting was well out of our league back then, and
the savannah theory is a poor straw-man, pitifully easy to knock over. If the
AAT is to be taken seriously it should compete with the more modern view of our
evolution.
So what did we hunt?
AFAIK (not that I have checked this, or anything), there are no species of
human which hunt without weapons. Even rabbits are beyond us. Okay, so a lucky
dive might get you one, but we are very poorly adapted to such techniques.
So maybe we were tool users to an extent, in that we chucked things at the
animals, or thwacked them? Quite possible.
Perhaps we were mainly herbivores, and only ate animals when we did get a
'lucky dive' onto a rabbit. More likely, this seems to fit out physiology a
little better. Possibly a combination of tool-usage for the hunting and
herbivorous for the rest?
This still does not explain any of our features, but it is at least a lifestyle
that a human could be expected to survive with, if not be perfectly adapted to.
Would you accept this as a viable strawman... er I mean 'working hypothesis'?
>Pa> >different microhabitats were available. A. boisei is found in
>Pa> >depositional environments that are indicative of wetter habitats than
>Pa> Which leads back to the $64k question. If bipedalism wasn't a savannah
>Pa> adaptation, what was it?
>Why don't you just *try* reading some semi-current theory? Get rid of
>your "treeless, waterless savannah" fixation and work with something
>more accurate. You give some evidence above of knowing that the treeless,
>waterless savannah you're using as a strawman versus the AAT is not
>accurate.
So, why =did= we go bipedal. From what I have so far heard it was a combination
of several forces which finally made us become bipedal.
First, we were reluctant to come down from the trees, but as they became
scarcer, we did shamble about on the ground, and we held onto things like
nearby branches to keep ourselves stable, as we were used to in the trees.
This caused bipedality, which was reinforced by sexual displays. We found that
when we did venture out into the sun this was a good preadaptation to coping
with the heat, which we then built upon with sweat glands, nakedness,
subcutaneous fat, and so forth.
>Pa> Display? No sign of sexual dimorphism.
>Perhaps you could try using complete enough sentences to make
>intelligible thoughts as well.
Don't pick on people's grammar, it is unbecoming of.
There is a certain amount of sexual dimorphism, visible mostly from the front
when standing (all statements are relative to the other gender, not to other
apes):
Females: Males
little body-hair lots body-hair
breasts no breasts
vagina penis
fat placement around the hips/thighs fat placement around the stomach
short tall
So, yes, we can have a workable theory that bipedalism was reinforced by sexual
displays.
[Note to americans: Quoting, or even reading the above might break that weird
new ruling your congree passed about pronography over the internet. Sorry about
that.]
>Pa> Temperature Regulation? But bipedalism didn't evolve on the savannah.
>You mean your "treeless, waterless savannah"?
Everyone but us AATers believes that the apes evolved in the place that is now
african savannah. So, our hypothetical 'working hypothesys' will have evolved
there. We now know that at this time it was a mosaic of habitats, so our
protohuman will be designed to cope with this mosaic.
>Pa> Speed? A new-born Gnu can out-run a mature human. You need a great 800m
>Pa> time to survive on the savannah.
>You think all animals which don't live in the deep forest, who instead
>live in semi-open savannah mosaic woodlands, can run as fast as
>antelope?
I think everything upwards of a mouse is too fast for a human. But for the sake
of argument I will say that there are a LOT of dodos and similar shambling
about on the savannah, so chucking rocks or thwacking them with sticks provides
an ample food source when combined with roots, berries, nuts, fruits, grubs,
tender leaves, certain seeds, blossoms, and of course miscellaneous frogs,
crabs, shellfish, etc as might be caught near streams.
Since there was an ample nearby water supply we can assume that there was no
problem getting as much water as was necessary to maintain sweat-cooling using
as much water as was necessary.
>Pa> Tool carrying? Bipedalism predates tools.
>Actually unlikely; you are confusing "stone tools" with "tools". Again,
>there's been *some* writing done on human evolution in the last 30 years.
Bipedalism predates tools, and no literature I have heard of denys this, but it
may well not predate improvised implements. The difference being, a tool is
something created to do a job, an implement is something around that does the
job just fine.
Our hypothetical protohuman was using gurt big thwacking branches on dodos.
>Pa> Food gathering? Lots of problems with disadvantageous intermediate
>Pa> forms.
>The non-existent "law of disadvantageous intermediates" again. Give it
>up, Pat; it doesn't exist.
Indeed. So out hypothetical protohuman could sling a brace of dodos over his
shoulder and shamble back into the trees where his dutiful spouse is waiting
collecting fruits. He makes his bipedal display, she hands over all the fruit,
and he magnanimously sheres it with her.
Okay, the social structure might be different, but that will do for the time
being.
>At any rate, leopards, except possibly in deep forest, do not "hunt from
>trees". Even a little study, or just casual watching of nature shows on
>the tube, would tell you that leopards in African open woodlands and
>savannah, hunt "from" the ground, and usually then carry their prey up
>into trees to get away from obnoxious prey-stealing beasties, such as
>hunting dogs and hyenas.
But not humans.
This was a good reason for the protohuman to base his society around the trees,
and only shamble out when the sun was not too high, to thwack a brace of dodos
and bring them back. There was also plenty of fruit and water (since the trees
would tend to be around water).
And if leopards etc came towards the trees, lookouts could scream, everyone
would jump into the trees and pelt the leopard, and the leopard would be driven
away without danger to the protohuman.
In fact, it is possible that he would shamble out when the sun was at its peak,
when all the predators were having their siesta, and hence a much safer time.
The prey would also feel less like running away at these times.
This gives a more logical reason for the wierd heat-regulation system
(bipedalism is only really an advantage at midday, we sweat far too much, but
then at midday we would have to, we have hair on our heads which would only
protect us at midday, etc)
So, would you say that our hypothetical protohuman, whom I shall call
australopithecus strawmanicus, is a valid contender, representing the latest
theories?
Are there any extra bits you would like to add? Any bits that do not fit with
the latest theories?
In particular, you need a reason for our lack of hair. Or you could deffer that
until later, when we started wearing clothes (no matter that there are tribes
that have never worn more than a loincloth). I guess it could be part of the
bipedal display bit.
Seriously, I am interested to know just what IS considered 'state of the art'.
--
- D. http://www.brad.ac.uk/~dmorgan/
J. Moore
Dm> of human which hunt without weapons.
Humans don't come in different species.
Dm> This caused bipedality,
Using "this caused _____" is a non-evolutionary view.
Dm> >Pa> Display? No sign of sexual dimorphism.
Dm> >Perhaps you could try using complete enough sentences to make
Dm> >intelligible thoughts as well.
Dm> Don't pick on people's grammar, it is unbecoming of.
I wasn't picking on his grammar, but rather the fact that he didn't
provide enough of a sentence to have any idea just what the hell he
meant to say.
Dm> >Pa> Tool carrying? Bipedalism predates tools.
Dm> >Actually unlikely; you are confusing "stone tools" with "tools".
Dm> Bipedalism predates tools, and no literature I have heard of denys this,
Dm> but it may well not predate improvised implements. The difference being,
Dm> a tool is something created to do a job, an implement is something
Dm> around that does the job just fine.
An "implement" and a "tool" are the same thing. Since chimpanzees,
among other animals, use tools, and chimpanzees even make them, we can
surmise that the ancestor we share with chimps was likely capable of
making them, and that australopithecines certainly were.
Dm> Seriously, I am interested to know just what IS considered 'state of the
Dm> art'.
Judging from the rest of your post, I cannot believe you are seriously
interested about the subject at all.
Pat Dooley
<< deletions>>
I wrote:
>Pa> Which leads back to the $64k question. If bipedalism wasn't a
savannah
>Pa> adaptation, what was it?
>
Moore responded:
>Why don't you just *try* reading some semi-current theory? Get rid of
>your "treeless, waterless savannah" fixation and work with something
>more accurate. You give some evidence above of knowing that the
treeless,
>waterless savannah you're using as a strawman versus the AAT is not
>accurate.
The recognition that humans probably didn't evolve bipedalism on the
savannah is relatively recent. The various accounts of how bipedalism
evolved that I have seen posted here and in the books that I have read
(Leakey, Johanson etc.) don't give a clear description of how such a
radical
evolutionary change as human bipedalism might have arisen. The two major
evolutionary problems are:
(i) If bipedalism is such a great adaptation, why is it restricted to
just one
primate species. I know this comment will set off Nicholls in
another
long-winded exposition about how human bipedalism is just a slight
exaggeration of an existing ape tendency towards bipedalism.
According to Richard Leakey and Roger Lewin "the evolutionary
shift from quadrupedalism to bipedalism
would have required an extensive remodeling of the ape's bone
and muscle architecture and of the overall proportion in the lower
half of the body. Mechanisms of gait are different, mechanics of
balance are different, functions of major muscles are different.
An entire functional complex had to be transformed for efficient
bipedalism to be possible." cf. "Origins Reconsidered". For your
own
edification, you might care to compare the skeletons of the
major ape species, mounted n their natural locomotive position.
Pay particular attention to the pelvis, the curvature of the spine,
the knees, and the position of the skull relative to the spine.
There is some major re-engineering required to get from the
proto-homind/ape model to the human model.
According to the DNA evidence, Chimps and Bonobos are
our closest relatives, and we are more closely related to them
than they are to Gorillas. You would never believe that was
the case based on comparative anatomy. What is even more
surprising is the short time frame in which those differences
emerged. Most of the skeletal transformation occurred in the
interval between the initial separation from the ape-line, say
7.5 mya, and the appearance of fully bipedal Australopithecus,
say 4 mya. That is extremely rapid evolution, and could only
have come about due to a major environmental change; a change
that somehow seems to have bypassed just about every other
mammal group in Africa over the same time scale.
By way of comparison, horses and the various zebra species are
more distantly related to each other than we are to chimpanzees.
However, there is nothing like the same degree of differences in
their
anatomy. If we suddenly discovered an equine species with a greatly
elongated neck, or a completely different gait, we would have
something comparable to the differences between humans and
other apes.
(ii) In all the scenarios that I've read, the problem of disadvantageous
intermediates gets short shrift. You have betrayed your
unfamiliarity
with evolutionary theory when you said:
>The non-existent "law of disadvantageous intermediates" again.
Give it
>up, Pat; it doesn't exist."
You might try reading Richard Dawkins "The Blind Watchmaker" before
making such a statement. It is a simple principle of evolution that
its progress
is not directed by the desirability of particular outcomes, but by
the
accumulation of small changes that are not, in themselves,
disadvantageous.
Eyes didn't evolve because 20:20 full colour vision is better than
being blind;
they evolved because every slight improvement from a patch of light
sensitive skin through to modern eyes provided the possessor with a
slight
evolutionary advantage over its forbears.
So it is with bipedalism. You cannot argue that bipedalism evolved
because
human bipedalism is more efficient, by whatever measure, than
knucklewalking.
You have to demonstrate that each intermediate form between the
ancestral
gait of the human/chimpanzee common ancestor, and the bipedal gait
of
Australopithicenes, was advantageous. Perhaps you have found an
explanation,
other than the aquatic theory, that explains the evolution of
bipedalism, with
its drastic skeletal changes, without introducing disadvantageous
intermediates.
(whether Australopithicenes were on the direct line of descent to
Homo Erectus
is irrelevant to the discussion).
>
>Pa> Display? No sign of sexual dimorphism.
>
>Perhaps you could try using complete enough sentences to make
>intelligible thoughts as well.
>
The idea that bipedalism evolved out of some form of display behaviour,
similar to the upright displays of male gorillas, fails to account for the
fact
that there is little difference between human males and females in their
size or degree of bipedalism.
>Pa> Temperature Regulation? But bipedalism didn't evolve on the savannah.
>
>You mean your "treeless, waterless savannah"?
Some posters are quite convinced bipedalism arose on the savannah. They
go to great lengths to claim our midday running ability in the pursuit of
prey was sufficient reason for the evolution of bipedalism.
>
>Pa> Speed? A new-born Gnu can out-run a mature human. You need a great
800m
>Pa> time to survive on the savannah.
>
>You think all animals which don't live in the deep forest, who instead
>live in semi-open savannah mosaic woodlands, can run as fast as
>antelope?
For the purposes of the discussion, we can ignore small burrowing mammals,
fully arboreal primates, spiny porcupines and the like. That said, we are
left
with animals that can:
(i) run fast enough and long enough to stay ahead of predators,
e.g. antelopes, zebras etc.
(ii) are too large for predators to tackle
e.g. rhinos
(iii) have a social organisation that allows them to fend off predators
e.g. chimpanzees and baboons.
(iv) can run off to the nearest trees and climb rapidly
e.g. baboons
Human ancestors could be presumed to adopt some combination of (iii)
and (iv). However, that supposition presents a number of problems.
Firstly, none of the other primates that adopt such a strategy has evolved
any of the human oddities such as bipedalism, hairlessness, sweating,
and subcutaneous fat. Secondly, it fails to address the problem of
disadvantageous intermediates. The ape in transition between a quadrupedal
gait and a bipedal gait would be slower than the ape at either side of the
transition. It's obvious that the last ape to reach the safety of a tree
would be
the first one eaten.
>
>Pa> Tool carrying? Bipedalism predates tools.
>
>Actually unlikely; you are confusing "stone tools" with "tools". Again,
>there's been *some* writing done on human evolution in the last 30 years.
You missed the point. It has been claimed that bipedalism evolved to
facilitate tool carrying. Perhaps the sight of chimpanzees rushing down a
hillside
brandishing branches torn off trees inspired that idea. However,
chimpanzees
do not carry such tools around with them; nor do they expend any effort
refining their tools. It is likely the first bipedal hominids used tools
in
much the same way as modern chimpanzees; the brain power was probably
comparable. But it is long after the evolution of bipedalism that any sign
of tools that are re-used emerges in the fossil record. If the tools
aren't being
re-used, they aren't being carried around by a bipedal ape.
>
>Pa> Food gathering? Lots of problems with disadvantageous intermediate
>Pa> forms.
>
>The non-existent "law of disadvantageous intermediates" again. Give it
>up, Pat; it doesn't exist.
>
See prior comments re Dawkins. I suppose you believe evolution is
directed;
that the advantages of the final outcome will outweigh the disadvantages
of the intermediate forms.
>Vi> Yesterday, my seventh grade son turned to me out of the blue and said
>Vi> "Ya know dad," (he'd been studying paleoanth as part of his social
>Vi> studies course last fall) "I was just thinking: how did early man
manage
>Vi> while he was just evolving onto two legs? It must have been awfully
>Vi> awkward while he was sort of in between." The only thing I could
reply
>Vi> was "this question is being hotly debated."
Sorry, but I don't have the attribution. However, this seventh grader
seems
to have a much better grasp of evolutionary theory than you.
<< stuff on leopards deleted.>>
Pat Dooley
Pat Dooley
> Likewise, the claim is made that an aquatic environment provided
>a refuge from predators. This is nonsense. For one thing, the
>weakness of humans in comparison with terrestrial predators (on a
>purely physical level) is even worse for humans in water wrt _aquatic_
>predators. I can (or could before my knees went to pot) run with a
>speed 25-30% of the _fastest_ land predator. An olympic swimmer
>would not make more than 5% of the fastest aquatic predators, and not
>more than 10% of more "typical" predators. Then, in the water, it is
more
>difficult to see predators coming and avoid them. Likewise, it is more
>difficult to band together to drive off a predator (as those chimps did).
>Also, aquatic predators are _stupid_ and unwilling to be driven off by
threat
>displays (unlike land based mammals).
Your points might have some validity if the proposed aquatic ape was an
ocean going swimmer. It is far more likely to have been a shore line
forager, rarely venturing into deep water. In such a case, it only has to
make it to the shallows to evade a shark or crocodile.
That option is not available to an ape trying to outrun a leopard.
Pat Dooley
Pat Dooley
>>Which leads back to the $64k question. If bipedalism wasn't a savannah
>>adaptation, what was it?
>>
>>Arboreal? The arms would be more orang like, and the legs much shorter.
>
Alex Duncan responded:
>How about this: hominids evolved from an ancestor that was so specialized
>for an arboreal existence that its only effective mean of terrestrial
>locomotion was bipedalism (see modern gibbons). In a fragmenting forest
>environment, those pre-hominids that were most adept at moving from tree
>to tree ON THE GROUND would have been selected for. An important thing
>to note here is that this model doesn't suggest that pre-hominids adapted
>bipedalism because living in open country was so wonderful. They did it
>because they needed to cross open country from one patch of trees to the
>next. As time went on, and aridification increased (e.g. terminal
>Miocene climatic event) the patches between trees became progressively
>larger and larger, selecting for more and more efficient bipeds.
>Eventually the adaptation to crossing open ground became effective enough
>that early hominids began other activities in open country (looking for
>food, etc.).
>
Hominids and modern chimpanzees share a common ancestor from about
7.5 mya. Gorillas branched off about 2 million years earlier. What you are
claiming for the ancestral hominds must also be true for chimpanzees and
gorillas; that their immediate ancestors were as arboreal as modern
gibbons. Even if this true, and I don't know if the fossil evidence
supports
the claim, the latter two never went through the major skeletal changes
required to support bipedalism when they moved to more open environments.
The problem with your scenario is that energy efficiency is far less
relevant
than other factors. The initial evolutionary imperative would have been to
minimise exposure on the ground rather than maximise energy efficiency.
Evolving a whole new mode of locomotion doesn't satisfy that imperative.
Walking fully upright rather than staying low doesn't satisfy that
imperative
either (those who claim that bipedalism makes it easier to spot predators
should realise that supposed advantage cuts both ways - it also makes it
much easier to be seen by predators).
Baboons and chimpanzees separately evolved similar strategies for living
in a savannah environment. They developed a social structure that
provided protection against predators and they retained good arboreal
skills. The males, especially in baboons, have powerful canines and
could certainly inflict significant damage on a leopoard.
It is hard to see how 100% bipedalism, reduced arboreal skills,
and increased visibility would prove a better strategy in the short-run.
>I can think of no oddities that wading and swimming fit in with. Please
>enlighten me. I'm not suggesting that early hominids didn't occasionally
>enter the water, but to postulate an aquatic existence as the precursor
>to all that is "hominid" flies in the face of all of the evidence I'm
>aware of.
It seems odd to me that humans have aquatic capabilities far greater
than those of any other apes or primates. Evolution doesn't fill your
kitbag with capabilities you never use nor ever used. In particular,
it doesn't equip you with conscious control over your breathing, if
you don't need it. It doesn't heighten your diving reflexes if you
don't need it. It doesn't give you a layer of subcutaneous fat if you
don't need it. It doesn't give you the ability to dive to 250 feet if you
never dive. It doesn't add salt to your tears and sweat if you never
needed to exude it. Yet, evolution bestowed all those useless gifts
on homo sapiens, and all in the last 7.5 million years. Despite having
98% of their DNA in common with us, chimpanzees share none of those
features with us. They also missed out on 100% bipedality,
eccrine sweating, and loss of most of their body hair.
Thus, when you propose a scenario for the evolution of bipedalism that
could equally well fit savannah chimpanzees yet fails to account for any
of
the other oddities, I have to wonder how plausible your scenario is.
Re Leopards and Taung. I should have checked my references
rather than relying on a memory showing premature signs of parity
errors. I got the name wrong and conflated another Australopithicene
fossil fragment with the Taung boy. The skull fragment showed two
puncture marks that match the space between a leopard's canines.
Pat Dooley
Pat Dooley
>It's easy to envision early hominids having some skill with water (i.e.,
>behavioral adaptation), but without a great deal of skeletal adaptation
in
>that direction. Look at cats--tigers take to the water easily, while most
>species avoid it. I suspect this can be tabled as having no strong
>evidence in either direction. In any case, hominids probably did not
>spend most of their time in the water. Not with limbs adapted to climbing
>and bridging.
Jaguars take to the water even better than tigers. They collect a
substantial
proportion of their prey from water. However, neither they, nor any other
primates, has the ability to dive to any depth.
The upper limit on unassisted human diving performance
is about 250 feet. Some human groups regularly dive to a depth of 80
feet. These aren't just learned capabilities - there are physiological
adaptations to support them, including conscious control over
breathing, a heightened diving reflex that slows the heart rate
down from 72 to 35 beats per minute, and an ability to hold ones
breath for 3 minutes or more.
Such features would not be surprising if our closest relatives
could achieve some significant fraction of these capabilities.
But, there is no sign of such capabilities in them or in other
fully terrestrial mammals.
It can also be argued that human limbs are partially adapted for
swimming and diving. In particular, a human being can swim or dive with
their arms, legs, head and body in a plane. That improves efficiency
and is a feature of most semi-aquatic and aquatic mammals.
There is also the issue of residual webbing in humans. That useless
flap of skin between your thumb and forefinger is the only thing
that restricts the movement of your thumb back another thirty degrees;
other apes don't have such a flap. A significant percentage of humans
still
have further vestigal webbing between their fingers and toes.
Pat Dooley
Pat Dooley
>(tools)--wood doesn't fossilize too well--weaponless 10 mph
>bipedalists?--weapons are what got us to where we are today--grow up!
>Cheers
>Barry
I should have been more precise. There is no evidence for tool making or
tool retention that predates Australopithicenes. That is not to say that
early hominds did not have the tool using capabilities of modern apes.
Pat D
Pete Vincent
(Quoting Dewi Morgan with a badly broken quoting software)
` Dm> AFAIK (not that I have checked this, or anything), there are no species
` Dm> of human which hunt without weapons.
`
` Humans don't come in different species.
H. habilis, h. erectus, h.sapiens. I count three anyway.
`
` Dm> This caused bipedality,
`
` Using "this caused _____" is a non-evolutionary view.
`
` Dm> >Pa> Display? No sign of sexual dimorphism.
` Dm> >Perhaps you could try using complete enough sentences to make
` Dm> >intelligible thoughts as well.
`
` Dm> Don't pick on people's grammar, it is unbecoming of.
`
` I wasn't picking on his grammar, but rather the fact that he didn't
` provide enough of a sentence to have any idea just what the hell he
` meant to say.
Oh, I think you can manage.
[..........]
`
` Dm> Seriously, I am interested to know just what IS considered 'state of the
` Dm> art'.
`
` Judging from the rest of your post, I cannot believe you are seriously
` interested about the subject at all.
`
Ah, so that's how you will avoid answering the question.
If you think your snotty atitude is an adequate substitute for
reasoned argument, you're dead wrong. You must be having a
bad day. I expect better from you.
==========================================================================
vin...@triumf.ca <== faster % Pete Vincent
vin...@freenet.vancouver.bc.ca % Disclaimer: all I know I
% learned from reading Usenet.
Barry Mennen
writes:
I winced when I read what I had written--I was in a bad mood that day
and would like to apologize for the childish tone of my post--you
obviously have much class in not replying to me in a similar manner--
Cheers
Barry M
David L Burkhead
>
>Your points might have some validity if the proposed aquatic ape was an
>ocean going swimmer. It is far more likely to have been a shore line
>forager, rarely venturing into deep water. In such a case, it only has to
It would have to make it to shallows too shallow for shark or
crocodile. For the shark, that would be, at best, no more than knee
deep and even that is uncertain. While sharks don't generally attack
prey in water that shallow they _can_. And crocodiles can follow your
fleeing pre-humans right up onto the shore if they wanted to. The
thing is, they'd not _have_ to. They are so much faster in the water
than humans that from the time the pre-humans would know they are
there, and the time they struck, a pre-human would only go a couple of
feet. The same for sharks in waist deep water. They are _so_ much
faster than humans in water that you don't have _time_ to get to the shallows.
In _real_ shark attacks (as opposed to the ones in movies) the
first sign that anyone has that the shark is even there is often when
the attackee notices that his _arm_ (or leg) is gone!
>
>That option is not available to an ape trying to outrun a leopard.
>
Still clinging to that "treeless, waterless savanna"? Fleeing
for the trees is comparable to fleeing for the shallows--and the race
is _much_ more even. Go look at my numbers again. The fastest human
swimmer there ever was is less than half as fast, compared to typical
swimming predators, as an average runner against the fastest land
predators.
And go look at how chimpanzees _actually_ deal with predators
like leopards. It's _not_, in general, by fleeing. They do, at least
on occassion, band together to _drive off_, or _kill_, the leopard.
There is no reason at all why our putative ancestors could not have
done the same thing.
The idea that an aquatic environment is, somehow, safer from
predators than a savannah environment (not the mythical "treeless,
waterless savannah" but a real one) is patently false.
Clara N. Fitzgerald
>JM> >Some gorillas, various macaques and the proboscis monkey spend
>JM> >varying amounts of time in all those places, but show none of the
>JM> >supposed AAH adatations. They utilise common ape and monkey locomotor
I had heard that probiscus (sp?) monkeys had been picked up by fishing
boats significant distances from land. You're saying that oxygen bell of
a nose couldn't possibly have anything to do with swimming?
There is an extinct species of swamp ape ( oreosticios ??? ) that
apparently shows some skeletal adaptions for bipedalism.
The descended larynx arrangment in humans seems sufficiently dangerous
(choking hazard, and bypassing the preheating and filtering provided by
the nasal cavity) to require some extraordinary explanation. I'm not
convinced that language is sufficient. When actually swimming (putting
one's head under), breathing in through one's nose usually brings in some
water with the air (problem with small openings and surface tension);
the mouth doesn't have this problem; water can get into the mouth, but
isn't swallowed.
>JM> >Various environments have been suggested by different AAH proponents;
>JM> >all state that a major reason that these water environments were
>JM> >necessary for the evolution of bipedalism is to help support the body
>JM> >weight of the animal. Note that this necessarily means that the animal
You've got it backwards; it is suggested that some support for body weight
was required to allow bipedalism (before anatomical changes had occured),
and water would perform that function. If it was rather easy and very
beneficial for the ape to stand up, why haven't the chimps or baboons tried it?
>Pa> What are the real advantages of wading compared to quadrupedalism?
We assume he meant 'bipedal vs. quadrupedal wading', as your reply assumes.
>This is a false dichotomy, or what Bateson would call a "confusion of
>logical types"; "wading" and "quadrapedalism" are not, as you claim
>here, mutually exclusive. Monkeys and apes which do go into water most
>often do so quadrapedally.
>Pa> 1) Better vision across the surface of the water and back to land.
>If the water isn't over your head, you can see "back to land" just
>fine with your head at the surface of the water. On land, however,
>bipedalism for this purpose would be a huge advantage.
It it's clear or fairly shallow water, you can see the bottom (rocks,
etc) which you can't see if your eyes are at the surface. You could also
see fish, patterns of ripples (sharks, etc) and get a sense of the currents
Please support the opinion that a wider view across land is more advantageous
than a similar view across water.
>Pa> 2) Lower energy usage compared to swimming.
>Refs, please. I've always found walking through water to be
>energy-intensive, as water gives such much resistance. But please do
>provide the references which contradict this impression.
Consider energy per unit of forward motion. Swimming uses a lot of
energy moving water around, only some of which also moves the swimmer forward.
>Perhaps you could explain how the AAT-hominids defended themselves
>against fierce aquatic predators such as crocodiles and sharks.
Besides knowing what areas and times to avoid (I would suspect that
early morning would be fairly safe against crocodiles ???), it's probable
there were losses; the birthrate could have made up for them.
What's the total yearly loss of lives to shark and crocs?
>Jim Moore (j#d#.mo...@canrem.com)
--
-Clara A. N. Fitzgerald cfit...@s.psych.uiuc.edu
- < - < -< <> >- > - > -
Help stamp out, reduce, and eliminate redundancy.
Clara N. Fitzgerald
>Pa> 2) Aboriginals make extensive use of water resources in the same areas
>Pa> as salt water crocodiles without suffering from population destroying
>Pa> predation. They know when and where it is safe to enter the water and
>Pa> where not to. White toursists are the usual victims in the rare cases
>Pa> where a human is taken, usually because they ignore the signs telling
>Pa> them to beware of crocodiles.
>think that was a possibility? What does the fact that modern land-based
>people with sophisticated weaponry, such as knives and spears (and of
>course guns now), do not suffer "population destroying predation" from
>water-living animals have to do with a transitional water-living
>population without these sophisticated weapons? Don't you even see the
My impression from the preceeding posts was that the trouble with
crocs and sharks was that you couldn't see them coming, and would be
dead before whatever weapon you had (What good is a gun going to do you?)
could help you. (Also that crocs don't let go once they have a bite.)
A stick would probably be as good as a spear; you wouldn't have a solid
place to apply pressure to cut through the skin. There is also this
phenomenon of crocodile-wrestling; if you can get its mouth closed, you
can hold it closed bare-handed.
>Aborigines do not, as the AAT requires, spend at least half their waking
>hours up to their waists, or above, in water.
There are certain waterside villages where inhabitants spend much of
the day (with short breaks) diving for shellfish.
>Nevertheless, a quote from *Crocodiles and Alligators of the World*
>(1991: 24): "The Australian Aborigines recognize differences in the risk
>from various crocodile populations. In some areas, they maintain that
>even Indo-Pacific crocodiles will not attack them, and they venture into
>the water at these localities. Nevertheless, Aborigines do fall victim
>to crocodiles, often when wading in water."
Apparently quite rarely, yes?
>Pa> 3) The argument that apes could not have adapted to an aquatic environment
>Pa> because of sharks or crocodiles is bogus. Both predators have been around
>Pa> when many other mammal species made the transistion from land to water.
>Pa> The pioneers must have been pretty clumsy in the water during the
>Pa> initial stages of the transition, but they made it.
>Pa> Pat Dooley
>Okay, name them; name some tropical mammals that:
>A) are about the size of these hominids (or smaller);
>B) spend 4-8 hours a day in waist-deep or deeper water; and
>C) reproduce as slowly as humans and chimps.
Manatee? (I don't know how they reproduce.) Something called Dugong(sp?)
Otters and various seals deal with sharks.
J. Moore
Pa> savannah is relatively recent.
No, the problem is that you equate "savannah" with "treeless, waterless
place". "Relatively recent" that we figured that hominids didn't evolve
in a sort of arid desert? Well, we're talking at least 20-30 years;
I suppose that *is* recent...in geological time.
Pa> If bipedalism is such a great adaptation, why is it restricted to
Pa> just one primate species. I know this comment will set off Nicholls
Pa> in another long-winded exposition about how human bipedalism is
Pa> just a slight exaggeration of an existing ape tendency towards
Pa> bipedalism.
I've never seen him make any comment which said that apes have a
"tendency towards bipedalism", only that bipedalism is one mode
of locomotion among many for *all* apes and monkeys. Bipedalism is
*not* "restricted to just one primate species". This is a fact,
and why this fact should upset you so is beyond me.
Pa> >Pa> Display? No sign of sexual dimorphism.
Pa> >
Pa> >Perhaps you could try using complete enough sentences to make
Pa> >intelligible thoughts as well.
Pa> >
Pa> The idea that bipedalism evolved out of some form of display behaviour,
Pa> similar to the upright displays of male gorillas, fails to account for
Pa> the fact
Pa> that there is little difference between human males and females in their
Pa> size or degree of bipedalism.
Thank you for clarifying your previously-incomprehensible thought; this
shows that your problem in understanding the role of display in
bipedalism is two-fold: (1) you're looking for a single *cause*, rather
than a suite of advantages; and (2) you apparently don't understand that
male humans and female humans are the same species, and that therefore
the changes in basic structure of one are very likely to be changes to
both.
Pa> For the purposes of the discussion, we can ignore small burrowing
Pa> mammals, fully arboreal primates, spiny porcupines and the like. That
Pa> said, we are left with animals that can:
Pa> (iii) have a social organisation that allows them to fend off
Pa> predators
Pa> e.g. chimpanzees and baboons.
Pa> (iv) can run off to the nearest trees and climb rapidly
Pa> e.g. baboons
Pa> Human ancestors could be presumed to adopt some combination of (iii) and
Pa> (iv).
Chimps can do your number iv as well, but they don't ordinarily have to.
So you're saying that we would have to be somewhat like our closest
relatives. I am astonished that you find it so difficult to believe
that we were undoubtedly like our closest relatives, as in fact we still
are.
Pa> It's obvious that the last ape to reach
Pa> the safety of a tree would be
Pa> the first one eaten.
See how chimps take care of the problem in similar environments.
You could get yourself a library card and use it, or just read what's
been available online here. David Burkhead did one or the other,
enabling him to point out to you:
Pa> In such a case, it only has
Pa> to make it to the shallows to evade a shark or crocodile.
DB> It would have to make it to shallows too shallow for shark or
DB> crocodile. For the shark, that would be, at best, no more than knee
DB> deep and even that is uncertain. While sharks don't generally attack
DB> prey in water that shallow they _can_. And crocodiles can follow your
DB> fleeing pre-humans right up onto the shore if they wanted to. The thing
DB> is, they'd not _have_ to. They are so much faster in the water than
DB> humans that from the time the pre-humans would know they are there, and
DB> the time they struck, a pre-human would only go a couple of feet. The
DB> same for sharks in waist deep water. They are _so_ much faster than
DB> humans in water that you don't have _time_ to get to the shallows.
DB> In _real_ shark attacks (as opposed to the ones in movies) the
DB> first sign that anyone has that the shark is even there is often when
DB> the attackee notices that his _arm_ (or leg) is gone!
(My note: crocodile attack too; victim rarely sees it coming.)
PD> >That option is not available to an ape trying to outrun a leopard.
DB> Still clinging to that "treeless, waterless savanna"? Fleeing for
DB> the trees is comparable to fleeing for the shallows--and the race is
DB> _much_ more even. Go look at my numbers again. The fastest human
DB> swimmer there ever was is less than half as fast, compared to typical
DB> swimming predators, as an average runner against the fastest land
DB> predators.
DB> And go look at how chimpanzees _actually_ deal with predators like
DB> leopards. It's _not_, in general, by fleeing. They do, at least on
DB> occassion, band together to _drive off_, or _kill_, the leopard. There
DB> is no reason at all why our putative ancestors could not have done the
DB> same thing.
DB> The idea that an aquatic environment is, somehow, safer from
DB> predators than a savannah environment (not the mythical "treeless,
DB> waterless savannah" but a real one) is patently false.
DB> David L. Burkhead
Pa> >Pa> Tool carrying? Bipedalism predates tools.
Pa> >
Pa> >Actually unlikely; you are confusing "stone tools" with "tools".
Pa> >Again,
Pa> >there's been *some* writing done on human evolution in the last 30
Pa> years.
Pa> You missed the point.
The point is that you said something that is almost certainly untrue.
Pa> Perhaps the sight of chimpanzees rushing down a hillside
Pa> brandishing branches torn off trees inspired that idea.
"Perhaps" it was the observation that bipedal locomotion in non-human
primates is often used when they carry more than can be gripped in one
hand.
Pa> However, chimpanzees
Pa> do not carry such tools around with them; nor do they expend any effort
Pa> refining their tools.
Pa> It is likely the first bipedal hominids used tools in
Pa> much the same way as modern chimpanzees; the brain power was probably
Pa> comparable. But it is long after the evolution of bipedalism that any
Pa> sign of tools that are re-used emerges in the fossil record. If the
Pa> tools aren't being re-used, they aren't being carried around by a
Pa> bipedal ape.
Chimps modify their tools. Chimps re-use tools. Maybe *your* ancestors
weren't as smart as chimps, but *mine* were. Tools "in the fossil
record" (actually stone tools are not "fossils", of course) are, so far,
stone tools, and our ability to recognise non-cutting stone tools, or
wooden tools, grasses, etc., at that time-distance is at present
essentially non-existent.
Pa> >Pa> Food gathering? Lots of problems with disadvantageous intermediate
Pa> >Pa> forms.
Pa> >
JM> >The non-existent "law of disadvantageous intermediates" again. Give it
JM> >up, Pat; it doesn't exist.
Pa> See prior comments re Dawkins. I suppose you believe evolution is
Pa> directed; that the advantages of the final outcome will outweigh
Pa> the disadvantages of the intermediate forms.
Pa> Pat Dooley
Building a strawman, Pat? Let's just look at your idea of "the
principle of disadvantageous intermediates" and how, many many posts
ago, I tried, for the umpteenth time, to get you to understand how it
doesn't exist:
Pa> Evolution doesn't give you a sub-optimal holiday while you evolve an
Pa> optimal solution - the principle of non-disadvantageous intermediates.
There is no such "principle", as has been pointed out to you many many
many many times so far. The idea that evolution produces "optimal"
behaviors or morphology is a popular misconception, but that's all it
is. Evolution does not force "optimal" results, it selects against
ones that don't work "well enough". The sooner you divorce the words
"optimal" and "evolution" from each other, the closer you'll be to an
understanding of evolutionary principles.
Pa> You might try reading Richard Dawkins "The Blind Watchmaker"
Pa> before making such a statement. It is a simple principle of
Pa> evolution that its progress
Pa> is not directed by the desirability of particular outcomes, but
Pa> by the accumulation of small changes that are not, in themselves,
Pa> disadvantageous.
Not *critically* disadvantageous; in other words, not so horribly wrong
that the creature couldn't survive long enough to raise a few kids to
the age where they raise some kids of their own.
Pa> You have to demonstrate that each intermediate form between the
Pa> ancestral
Pa> gait of the human/chimpanzee common ancestor, and the bipedal
Pa> gait of Australopithicenes, was advantageous.
No, you don't show that it was *advantageous*, but rather that it *was
not* horribly disadvantageous. You know, like standing around in
crocodile-infested water 4-8 hours a day would be.
Harry Erwin
Dooley) wrote:
> j#d#.mo...@canrem.com (J. Moore)
>
> << deletions>>
> ---trimmed---
> The recognition that humans probably didn't evolve bipedalism on the
> savannah is relatively recent. The various accounts of how bipedalism
> evolved that I have seen posted here and in the books that I have read
> (Leakey, Johanson etc.) don't give a clear description of how such a
> radical
> evolutionary change as human bipedalism might have arisen. The two major
> evolutionary problems are:
>
> (i) If bipedalism is such a great adaptation, why is it restricted to
> just one
> primate species. I know this comment will set off Nicholls in
> another
> long-winded exposition about how human bipedalism is just a slight
> exaggeration of an existing ape tendency towards bipedalism.
Actually, bipedalism has been an adaptation followed by perhaps a dozen
primate species, some simultaneously. However, the initial acquisition
does need a 'just so' story. That's why I'm suspicious that the earliest
hominids, perhaps 6 MYr ago, were not much bigger than gibbons and
significantly more arboreal than modern Pan/Gorilla, which appear to me to
have adaptations towards terrestrial quadrupedalism. That would give us an
ancestor with a propensity towards terrestrial bipedalism and with a low
enough weight that use of forelimbs in terrestrial locomotion would not
have significantly increased mobility.
>---trimmed---
>
> According to the DNA evidence, Chimps and Bonobos are
> our closest relatives, and we are more closely related to them
> than they are to Gorillas. You would never believe that was
> the case based on comparative anatomy. What is even more
> surprising is the short time frame in which those differences
> emerged. Most of the skeletal transformation occurred in the
> interval between the initial separation from the ape-line, say
> 7.5 mya, and the appearance of fully bipedal Australopithecus,
> say 4 mya. That is extremely rapid evolution, and could only
> have come about due to a major environmental change; a change
> that somehow seems to have bypassed just about every other
> mammal group in Africa over the same time scale.
There was a major environmental change at that time--deforestation as mean
temperatures decreased, grasslands spread, and conditions became more
continental. Investigate the spread of the 'Hipparion' fauna for some
insight. In any case, biological innovations can occur in the absence of
external causes. A number of groups experienced explosive radiations about
that time. We now know that the genetic clock varies in its speed very
markedly.
> ---trimmed---
> Give it
> >up, Pat; it doesn't exist."
> You might try reading Richard Dawkins "The Blind Watchmaker" before
> making such a statement. It is a simple principle of evolution that
> its progress
> is not directed by the desirability of particular outcomes, but by
> the
> accumulation of small changes that are not, in themselves,
> disadvantageous.
It's _quite_ a bit more complex than you're indicating here. Almost all
features are at fixation at any given time.
> Eyes didn't evolve because 20:20 full colour vision is better than
> being blind;
> they evolved because every slight improvement from a patch of light
> sensitive skin through to modern eyes provided the possessor with a
> slight
> evolutionary advantage over its forbears.
That would imply continuous evolution down a selective gradient. That only
occurs for relatively short periods of time since it is exponentially
fast.
> So it is with bipedalism. You cannot argue that bipedalism evolved
> because
> human bipedalism is more efficient, by whatever measure, than
> knucklewalking.
It isn't. It's also no less efficient (Bishop-Cannings Theorem).
Interestingly, we lack evidence that knuckle-walking is as old as
bipedalism. Side question: what _did_ those Miocene ground apes _do_ on
the ground???
>---trimmed---
> For the purposes of the discussion, we can ignore small burrowing mammals,
> fully arboreal primates, spiny porcupines and the like. That said, we are
> left
> with animals that can:
> (i) run fast enough and long enough to stay ahead of predators,
> e.g. antelopes, zebras etc.
> (ii) are too large for predators to tackle
> e.g. rhinos
> (iii) have a social organisation that allows them to fend off predators
> e.g. chimpanzees and baboons.
> (iv) can run off to the nearest trees and climb rapidly
> e.g. baboons
> Human ancestors could be presumed to adopt some combination of (iii)
> and (iv). However, that supposition presents a number of problems.
> Firstly, none of the other primates that adopt such a strategy has evolved
> any of the human oddities such as bipedalism, hairlessness, sweating,
> and subcutaneous fat. Secondly, it fails to address the problem of
> disadvantageous intermediates. The ape in transition between a quadrupedal
> gait and a bipedal gait would be slower than the ape at either side of the
> transition. It's obvious that the last ape to reach the safety of a tree
> would be
> the first one eaten.
The large ground-dwelling primates (Gorilla, Theropithecus,
Gigantopithecus, and Archaeolemur) appear to have evolved a 'sitting'
strategy. Basically, they sat down to eat, and often moved from place to
place by 'scooting' quadrupedally on their arse. That's hardly as fast a
movement strategy as bipedalism. A bipedal ape would have been the first
one to _see_ the threat or opportunity, and so could have been the _first_
one to reach the tree or the food.
>---trimmed---
> >
> >Pa> Food gathering? Lots of problems with disadvantageous intermediate
> >Pa> forms.
Interestingly, the cercopithecines and colobines are believed to have been
originally terrestrial quadrupeds with arboreal skills. Their solution to
the food gathering problem was cheek pouches. Only in the largest forms do
we see full terrestrialism and loss of the cheek pouches. Holding food in
the hands or in the cheeks both work.
>---Cheers,
--
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin (try again if necessary)
Harry Erwin
Dooley) wrote:
> David L. Burkhead wrote:
> ---trimmed---
> Your points might have some validity if the proposed aquatic ape was an
> ocean going swimmer. It is far more likely to have been a shore line
> forager, rarely venturing into deep water. In such a case, it only has to
> make it to the shallows to evade a shark or crocodile.
>
> That option is not available to an ape trying to outrun a leopard.
Certainly it is. An ape in a tree is much more mobile than a leopard. The
accessible space to a large carnivore with convergent pes and manus is
limited to the tops of some large branches, while a smaller ape with
grasping pes and manus could reach at least twice (prabably ten times) as
much volume.
>
> Pat Dooley
> Plainly, the AAH doesn't hold water.
--
Harry Erwin
Dooley) wrote:
> her...@osf1.gmu.edu (HARRY R. ERWIN) wrote (in part):
>
> >It's easy to envision early hominids having some skill with water (i.e.,
> >behavioral adaptation), but without a great deal of skeletal adaptation
> in
> >that direction. Look at cats--tigers take to the water easily, while most
> >species avoid it. I suspect this can be tabled as having no strong
> >evidence in either direction. In any case, hominids probably did not
> >spend most of their time in the water. Not with limbs adapted to climbing
>
> >and bridging.
>
> Jaguars take to the water even better than tigers. They collect a
> substantial
> proportion of their prey from water. However, neither they, nor any other
> primates, has the ability to dive to any depth.
>
> The upper limit on unassisted human diving performance
> is about 250 feet. Some human groups regularly dive to a depth of 80
> feet. These aren't just learned capabilities - there are physiological
> adaptations to support them, including conscious control over
> breathing, a heightened diving reflex that slows the heart rate
> down from 72 to 35 beats per minute, and an ability to hold ones
> breath for 3 minutes or more.
These are features that could have been acquired fairly late, especially
since they are nervous system adaptations, an area where biological
innovations are known to be particularly easy. Fixation would have taken
no more than 1000 generations. My suspicion is that the connection of the
emergence of modern man with the appearence of sea-going cultures might be
related.
>
> Such features would not be surprising if our closest relatives
> could achieve some significant fraction of these capabilities.
> But, there is no sign of such capabilities in them or in other
> fully terrestrial mammals.
>
> It can also be argued that human limbs are partially adapted for
> swimming and diving. In particular, a human being can swim or dive with
> their arms, legs, head and body in a plane. That improves efficiency
> and is a feature of most semi-aquatic and aquatic mammals.
Ah! I see your argument. Unfortunately, those features are also useful for
arboreal movement of small apes.
>
> There is also the issue of residual webbing in humans. That useless
> flap of skin between your thumb and forefinger is the only thing
> that restricts the movement of your thumb back another thirty degrees;
> other apes don't have such a flap. A significant percentage of humans
> still
> have further vestigal webbing between their fingers and toes.
The thumb/first-finger web is the primary path by which large external
forces are coupled to the hand structure in man. In the apes, the thumb is
reduced or (in the gibbons) adapted to swing out of the way and the forces
are transmitted via the fingers, which are vulnerable to breakage and
other injury and so must be fairly tough and indelicate. Yes, the web
restricts thumb mobility, but it allows the thumb and fingers to be
delicate manipulatory appendages with a reduced risk of damage.
--
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin (try again if necessary)
Harry Erwin
Dooley) wrote:
It does. Not quite as arboreal as gibbons but definitely as arboreal as
orangs. Proconsul africanus for example.
> the latter two never went through the major skeletal changes
> required to support bipedalism when they moved to more open environments.
Gorillas followed a different strategy, also adopted by Theropithecus,
Archaeolemur, and Gigantopithecus, of seated feeding, and quadrupedal
'scooting' on one's arse. There are suspicions (presented in a Nature
editorial in the same issue where A. ramidus was announced) that the
bipedal ramidine apes were the ancestors of Pan and possibly Gorilla.
>
> The problem with your scenario is that energy efficiency is far less
> relevant
> than other factors. The initial evolutionary imperative would have been to
> minimise exposure on the ground rather than maximise energy efficiency.
> Evolving a whole new mode of locomotion doesn't satisfy that imperative.
To minimize _risk_, not exposure. They are very different.
> Walking fully upright rather than staying low doesn't satisfy that
> imperative
> either (those who claim that bipedalism makes it easier to spot predators
> should realise that supposed advantage cuts both ways - it also makes it
> much easier to be seen by predators).
The advantage is very much with the prey in this exchange. There are
species that deliberately show themselves to predators that they've
detected. Apparently it is selectively advantageous in dealing with ambush
predators to let them know that they've been seen so they don't waste your
time and energy. I did a lot of work in ESS theory in this area about 10
years ago (presented at the Sheffield ESS workshop in 1987), and it was
clear that efficient information exchange between predator and prey was to
the clear advantage of _both_ if the ambush was not going to work.
>
> Baboons and chimpanzees separately evolved similar strategies for living
> in a savannah environment. They developed a social structure that
> provided protection against predators and they retained good arboreal
> skills. The males, especially in baboons, have powerful canines and
> could certainly inflict significant damage on a leopoard.
Chimps have reduced canines relative to their arboreal ancestors! The
behavioral _differences_ between chimps and baboons are marked.
>
> It is hard to see how 100% bipedalism, reduced arboreal skills,
> and increased visibility would prove a better strategy in the short-run.
See above. Joel Brown's thesis addressed this, as did my ESS research.
>
> >I can think of no oddities that wading and swimming fit in with. Please
> >enlighten me. I'm not suggesting that early hominids didn't occasionally
> >enter the water, but to postulate an aquatic existence as the precursor
> >to all that is "hominid" flies in the face of all of the evidence I'm
> >aware of.
>
> It seems odd to me that humans have aquatic capabilities far greater
> than those of any other apes or primates. Evolution doesn't fill your
> kitbag with capabilities you never use nor ever used. In particular,
> it doesn't equip you with conscious control over your breathing, if
> you don't need it. It doesn't heighten your diving reflexes if you
> don't need it. It doesn't give you a layer of subcutaneous fat if you
> don't need it. It doesn't give you the ability to dive to 250 feet if you
> never dive. It doesn't add salt to your tears and sweat if you never
> needed to exude it. Yet, evolution bestowed all those useless gifts
> on homo sapiens, and all in the last 7.5 million years. Despite having
> 98% of their DNA in common with us, chimpanzees share none of those
> features with us. They also missed out on 100% bipedality,
> eccrine sweating, and loss of most of their body hair.
Actually it can, but you have to understand how innovations reach
fixation. The term you should check out is 'hitch-hiking.'
> ---trimmed---
Pat Dooley
Pa> The recognition that humans probably didn't evolve bipedalism on the
>Pa> savannah is relatively recent.
>
>No, the problem is that you equate "savannah" with "treeless, waterless
>place". "Relatively recent" that we figured that hominids didn't evolve
>in a sort of arid desert? Well, we're talking at least 20-30 years;
>I suppose that *is* recent...in geological time.
I have never claimed the savannah was a treeless, waterless desert.
My understanding is that the savannah is a relatively open environment;
that trees are in isolated clumps rather than in a continous forest; that
the
seasons can be divided into a wet and dry season rather than the four
seasons of temperate climates; that the days in the dry season can
be extremely hot; the nights quite chilly etc. etc.
>
>Pa> If bipedalism is such a great adaptation, why is it restricted to
>Pa> just one primate species. I know this comment will set off Nicholls
>Pa> in another long-winded exposition about how human bipedalism is
>Pa> just a slight exaggeration of an existing ape tendency towards
>Pa> bipedalism.
>
>I've never seen him make any comment which said that apes have a
>"tendency towards bipedalism", only that bipedalism is one mode
>of locomotion among many for *all* apes and monkeys. Bipedalism is
>*not* "restricted to just one primate species". This is a fact,
>and why this fact should upset you so is beyond me.
In that case, please advise which other primates have gone through the
major skeletal changes that constrain them to 100% bipedalism.
(Gibbons don't work; they are virtually 100% arboreal and so far off
the human line as to be irrelevant to the discussion).
>
<< deletions >>
>Thank you for clarifying your previously-incomprehensible thought; this
>shows that your problem in understanding the role of display in
>bipedalism is two-fold: (1) you're looking for a single *cause*, rather
>than a suite of advantages; and (2) you apparently don't understand that
>male humans and female humans are the same species, and that therefore
>the changes in basic structure of one are very likely to be changes to
>both.
I don't care whether we have one evolutionary factor propelling the
evolution of 100% bipedalism or a number of interacting factors. What I
would want to see is an explanation that deals with the reasons why
Australopithecenes is bipedal and all its primate relatives in similar
environments stayed quadrupedal. To put it another way, the human
skeleton is radically different to that of a gorilla or chimpanzee or
bonobo, and those differences are all a consequence of the fact that
humans are truly bipedal. The other guys show no such shift from
the original ape stock of 7 mya. What forced Australopithecenes
to go bipedal.
Anyone with the faintest knowledge of zoology can give you
examples of sexual dimorphism. Gorillas are the closest example.
<< More deletions>>
>So you're saying that we would have to be somewhat like our closest
>relatives. I am astonished that you find it so difficult to believe
>that we were undoubtedly like our closest relatives, as in fact we still
>are.
When I see a sweating,hairless chimpanzee walking exclusively on two
legs, that can, when so conditioned, dive regularly to depths of 80 feet,
for 4 or more hours per day, I might believe that our closest DNA
relatives
are as like us as the DNA evidence would suggest.
>
>Pa> It's obvious that the last ape to reach
>Pa> the safety of a tree would be
>Pa> the first one eaten.
>
>See how chimps take care of the problem in similar environments.
You miss the point. I was referring to species, and to the old joke
about the two safari hunters who, when they were out of ammunition,
were confonted by a rather hungry lion. Hunter #1 says, "Let's run".
#2 says, "Why? The lion can run faster than either of us.". #1 replies,
"Yes, but I can run faster than you." The tottering ape going through
the transition to exclusive bipedalism would always be #2 - what
I'd call a "disadvantageous intermediate".
>
>You could get yourself a library card and use it, or just read what's
>been available online here. David Burkhead did one or the other,
>enabling him to point out to you:
<< yet more nonense about sharks deleted>>
Shark attacks on humans are so rare they are ranked with lightening
strikes.
If you are unlucky enough to get struck by one, you probably won't
see it coming and will have little time left to you to reflect on the fact
that of all the millions of people who swim and dive in the ocean, you
were the poor sucker that drew the short straw, even after surviving the
rather more hazardous drive to the beach.
The point remains; there is no evidence that sharks would have been
a major predator of semi-bipedal apes frolicking in the shallows.
<< deletions>>
>PD> >That option is not available to an ape trying to outrun a leopard.
>
>DB> Still clinging to that "treeless, waterless savanna"? Fleeing
for
>DB> the trees is comparable to fleeing for the shallows--and the race is
>DB> _much_ more even. Go look at my numbers again. The fastest human
>DB> swimmer there ever was is less than half as fast, compared to typical
>DB> swimming predators, as an average runner against the fastest land
>DB> predators.
If a semi-bipedal ape being pursued by a leopard tried to escape up a
tree,
I suspect it wouldn't have a hope in hades. If a land mammal makes it to
shore when pursued by a crocodile, it is generally safe. (Just saw nature
program showing hapless zebras stupidly trying to cross crocodile
infested waters despite ample evidence that preceding zebras were
having a little difficult with the crocs. Those that got ashore were not
pursued, although some lions were waiting to catch the injured).
>DB> The idea that an aquatic environment is, somehow, safer from
>DB> predators than a savannah environment (not the mythical "treeless,
>DB> waterless savannah" but a real one) is patently false.
>DB> David L. Burkhead
On statistical grounds alone we can dismiss the shark threat. Whether or
not apes marooned on Danakil island had anything to fear from mythical
African Salt Water crocodiles remains to be seen.
>
>
>Chimps modify their tools. Chimps re-use tools. Maybe *your* ancestors
>weren't as smart as chimps, but *mine* were. Tools "in the fossil
>record" (actually stone tools are not "fossils", of course) are, so far,
>stone tools, and our ability to recognise non-cutting stone tools, or
>wooden tools, grasses, etc., at that time-distance is at present
>essentially non-existent.
It might distress you to know this, but it is easily proven by simple
mathematics that every human living today has a common ancestor.
Since you claim your ancestors are not mine, I can only assume you
are claiming not to be human.
Recognizable human tools date from around 2.6 mya, about 1.4 million years
after the emergence of bipedalism. The only point I was making is that it
is
difficult to claim humans evolved bipedalism to free two hands to carry
tools, when there is no sign that they were significant tool users 4 mya.
You mention chimpanzees; they were evolving alonside humans, for the
same time period. They make rudimentary use of tools now. How good were
their ancestors 4 million years ago?
>
<< yet more deletions>>
>
>Pa> You might try reading Richard Dawkins "The Blind Watchmaker"
>Pa> before making such a statement. It is a simple principle of
>Pa> evolution that its progress
>Pa> is not directed by the desirability of particular outcomes, but
>Pa> by the accumulation of small changes that are not, in themselves,
>Pa> disadvantageous.
>
>Not *critically* disadvantageous; in other words, not so horribly wrong
>that the creature couldn't survive long enough to raise a few kids to
>the age where they raise some kids of their own.
Evolution proceeds randomly and over a long time scale. The slightest
mutation that enhances survival will become the norm; the disadvantageous
mutations, no matter how slight, die out, in the long run.
Yeah, some of the disadvantageous forms will survive and breed
successfully,
but, over time, they will become an increasingly smaller fraction of the
population.
At some point, that fraction becomes zero.
The point is that the slightest disadvantage in the short term translates
into
extinction in the long run.
You obviously don't understand that process or you would not have used
the phrase "critically disadvantageous" and gone on about surving "long
enough
to raise a few kids". Since your understanding of evolution is so limited,
it
is obviously pointless to discuss the problem of disadvantageous
intermediates
with you.
>
>Pa> You have to demonstrate that each intermediate form between the
>Pa> ancestral
>Pa> gait of the human/chimpanzee common ancestor, and the bipedal
>Pa> gait of Australopithicenes, was advantageous.
>
>No, you don't show that it was *advantageous*, but rather that it *was
>not* horribly disadvantageous.
>
Oh dear. I see you believe that evolution will proceed so long as the
adaptations are not "horribly disadvantageous". That's about on a par
with Lamarckism.
>You know, like standing around in crocodile-infested water
>4-8 hours a day would be.
Now, that's a great example of a strawman argument for you.
Pat Dooley
Pat Dooley
>From: j#d#.mo...@canrem.com (J. Moore)
>Date: Tue, 4 Jul 95 12:09:00 -0500
>Message-ID: <60.1961.72...@canrem.com>
>
>JM> >This means that merely walking along tidal flats, or river or lake
>JM> >shores, or even wading into knee-deep or even deeper water, no
matter
>JM> >how common, *is not* an AAT scenario. The AAT requires that a
>JM> >majority of our locomotion take place in water that supports us,
>JM> >which means water that is more than waist-deep, and probably
>JM> >considerably deeper. Water up to your rear, for instance, does
>JM> >not support you. Even water up to your waist doesn't provide this
>JM> >supposedly required support.
>
>Pa> You are misrepresenting the argument.
>
>According to the AAT, these primates could not have stood and walked
>bipedally unless supported by water (in spite of the fact that all apes
>and monkeys can do so now).
>
>Pa> Many modern primate
>Pa> species have been observed to wade bipedally (macaques, bonobos,
>Pa> proboscis monkeys, even gorillas, apparently).
>
>My god, Pat, you can't read at all, can you? I've posted several times
>on gorillas, and all their locomotion in water has been typical gorilla
>locomotion, as they do on dry ground. You are also (again) equating
>"wading" with "always bipedal", which is foolish when you first do it,
>but when you persist in such a confused equation after it's been pointed
>out to you, it's just stupid. Do you *want* people to thing you're
>stupid? If not, read and learn.
I apologise for implying that gorillas might wade bipedally. I have enough
difficulty wading through your posts. The fact remains that the other
species
I named do wade bipedally. I've even seen them do it on TV.
>
>Pa> If an ape was forced by a
>Pa> changing environment to forage in shallow water, then it is
reasonable
>Pa> to suppose that they might have done it bipedally.
>
>No, it is "reasonable to suppose" that they would do it the way they
>*actually* do it, with their typical mix of locomotor modes (ie., mostly
>quadrapedal and sitting with some bipedalism, just as they do on dry
>land). (You know, after the Dark Ages, people did come up with the
>radical idea of actually observing the world around them. Well, *some*
>people.)
The advantage of wading bipedally over wading quadrupedally is that
you can do more wading and less swimmimg; something primates are
generally averse to. Of course, you may have observed chimpanzees
swimming and diving.
>
>Pa> At that point, the AA would have moved from its usual quadrupedal
gait
>Pa> to a more bipedal gait. It would be able to extend its feeding range,
to
>Pa> gain an evolutionary advantage, and had the support of the water to
>Pa> overcome some of the stresses associated with the change in posture.
>
>According to the AAT, your above thesis wouldn't work, because,
>according to the AAT, these primates could not have stood and walked
>bipedally unless supported by water (in spite of the fact that all apes
>and monkeys can do so now).
>
There you go again, misrepresenting a position. All apes can walk on
two legs to some extent. The proto aquatic ape could certainly have
walked on two legs without the support of water, just as Macaques,
Bonobos and Proboscis monkeys do today. The support provided by
the water may have made it easier for them to maintain that unnatural
position.
>Pa> >1. We know that our close relatives, chimpanzees, survive in spite
of
>Pa> > large terrestrial predators in open savannah woodland (and in
fact
>Pa> > apparently do so more ably than their forest cousins), and we
have
>Pa> > observations of them in the wild that show us how they do so.
How
>Pa> > did the postulated aquatic transitional population deal with
common
>Pa> > aquatic predators such as crocodiles and sharks?
>
>Pa> Shark attacks on humans are very rare, despite the millions of people
>Pa> who swim, dive and surf in the ocean. That is likely to have been the
>Pa> case 5 mya.
>
>They had shark nets and guns? I don't think so, Pat. What about
>crocodiles? Oh yes, you said:
Your arrogance and ignorance know no bounds. The diving women of Japan
and South Korea work up to 4 hours a day in open ocean without benefit
of shark nets or guns. Some Indonesian cultures spend up to 4 hours per
day in the water without worrying about sharks. Aboriginal women in
the Northern Territory wade neck deep in water collecting various
delicacies such as a rather placid though largish snake species
without worrying about crocodiles. Tens
of thousands of tourists go snorkling on the Great Barrier Reef off the
coast of Queensland without worrying about sharks and they don't
have shark nets there, either.
And where did you get the stupid idea that guns provided any defense
against sharks? JAWS?
Pray tell, what sort of sharks and crocodiles infested the ancient salty
waters of the Afar sea.
>
>Pa> It is also possible that the ancestral aquatic apes were isolated on
>Pa> islands
>Pa> when the Sea of Afar was initially formed; thus crocodiles may not
have
>Pa> been anywhere near their environment.
>
>So your sole thought on the subject is that maybe they just weren't
>around there... That, maybe the most ubiquitous large predator in
>Africa, which is found in interior rivers and lakes as well as in
>coastal areas, on the beaches and in the oceans off Africa, on offshore
>islands over 20 miles from the mainland, well over 100 miles off the
>coast of Africa on Madagascar, not to mention having been known to exist
>even in lakes and waterholes in the interior of Mauritania, southeastern
>Algeria, and northeastern Chad in the Sahara Desert, *just didn't happen
>to be around that one area out of all of Africa*?!
If crocodiles were such a prevalent predator of trainee marine
mammals, as you suggest, then nothing would have made the transition
from land to water. No Otariidae, no Pinipeds, no Phocids, no Cetacea, no
Sirenia, no nothing.
And if they are such effective predators as you claim, the mere act of
drinking would have wiped out complete species. A whole panoply of
warm blooded highly efficient predators roam Africa, but that doesn't mean
their prey go extinct or stop evolving.
Your crocodile argument remains bogus.
>
>Pat, if someone like Leakey, Johanson, Henry, Tanner, Zihlman, Potts,
>Pilbeam, or White used the argument that our ancestors didn't need to
>worry about land-based predators because these predators "may not have
>been anywhere near their environment", I'd tell them they were nuts, and
>to come up with a real argument. I'll accord you the same treatment I'd
>give them: Pat, you're nuts; come up with a real argument.
One of the reasons why I suggested that humans could not have
evolved bipedalism on the savannah was because of the efficiency of
savannah
predators. You promptly responded by saying they didn't evolve on the
savannah.
Whether or not you realised it, you used exactly the same argument as the
one you're crying nuts about now.
>
>Pa> But the shark/crocodile argument is bogus anyway. Under that
scenario,
>Pa> no mammal could have made the transition from land to sea, yet we
know
>Pa> many species did - their descendants bear testimony to their success
in
>Pa> evading sharks and crocodiles and parasites and stone fish and so
on...
>
>Name one that's around the size of the common ancestor
>(australopithecine/chimpanzee sized), swims as fast as we can (I'll
>give them the [unlikely] speed of the fastest Olympic swimmers:
>5.1048 mph), spends 4-8 hours a day up in 3-4 feet of water, and
>which reproduces as slowly as do chimps and humans who gather/hunt today.
>Please, I asked you before, but you've not complied: name one.
The ancestor of the whale was a shoreline scavenger of moderate size. As
a low slung quadruped, its water speed could not have been great. The
fossils of this ancient creature were found in the remains of an ancient
sea that
covered northern Pakistan (i.e. warm enough for crocodiles).
But, since you have been so intemperate as to call me nuts, you might care
to atone by listing the land based ancestors of each and every aquatic
mammal that
would not qualify, due to its large size and/or incredible swimming speed,
as
potential crocodile fodder.
>
>JM > 2. Why don't humans have really small ears (or no external ears)
like
>JM > virtually all aquatic mammals?
>
>Pa> The size of external ears in aquatic mammals depends on how aquatic
they
>Pa> are. Sea lions have residual external ears, as do otters. The AAT
>Pa> suggests that early hominids became partially adapted to an aquatic
>Pa> lifestyle; probably not much more than can be seen in some human
>Pa> cultures today. The time span for the aquatic phase was not long
enough
>Pa> for such features as external ears to disappear.
>
>I do not use the non-evolutionary view that's inherent in the AAT: that
>all animals in an environment should resemble other distantly-related
>animals in that environment rather than their close relatives. But the
>AAT supporters continually do so, so that's why I'm asking you: The AAT
>says that a land-based transition didn't happen because we didn't evolve
>with the same features as such distantly-related animals as camels and
>the wild ass. It also says we evolved, extremely rapidly, the same
>features as such distantly-related animals as seals, whales, dugongs,
>etc. (not to mention crocodiles and birds). Given that *your* theory,
>not mine, says we *must* evolve such unlikely features very rapidly, I
>don't see why you then claim the "time span for the aquatic phase was
>not long enough for such features as external ears to disappear".
>
Besides not giving any credence to the principle of non-disadvantageous
intermediates, you seem to have no interest in the principle of convergent
evolution, either.
You will no doubt recall that the AAT has never proposed a 100% aquatic
phase. Your range of 4-8 hours per day seem an adequate figure for the
sake of argument. So, the AA has to spend a lot of time on land, and
losing
the ability to determine the direction from which a sound is coming seems
not to be a sound idea, so to speak. Our lugs are quite effective in
giving
us stereo hearing.
>JM> >3. The AAT says our pattern of hair orientation is due to water flow
>JM> > while
>JM> > swimming. This requires that a great deal of time be spent
swimming
>JM> > with the crown of our heads forward and our arms along our sides,
>JM> > pointing toward our feet.
>
>Pa> The flow patterns are seen in residual body hair, not just the head.
>Pa> >
>Pa> > A. How did we swim in this position?
>Pa> >
>Pa> Modern humans generally find they the most efficient way to swim or
dive
>Pa> is with the crown of the head forward. The arms usually point forward
at
>Pa> the start of stroke and finish at the side of the body at the end of
a
>Pa> stroke.
>
>This position, the "freestyle" stroke, does not keep the arms pointed
>down along the sides, therefore it cannot be the swimming stroke
>allegedly used for several million years to get our hair pointing the
>way it does. Further, you'll notice that even freestyle swimmers most
>often have the *tops* of their heads forward, not the *crown*, which is
>toward the back of the head.
>
The hair pattern that most took Sir Alister Hardy's fancy was the one
along
the back, not the crown of the head. By the way, freestyle swimmers do
keep their heads in the same relative position to the spine as they would
in
a standing position. This has the advantage of positioning the nostrils so
that
they stop water being forced up the nasal passages. Yet another reason why
chimps and gorillas make poor aquanauts; those outward facing nostrils.
>Pa> > B. How did we breathe while swimming in this position?
>
>Pa> Generally, one raises one's head out of the water and takes a breath.
>Pa> The smarter swimmers turn their heads sideways while keeping the
crown
>Pa> pointing forward.
>
>Pa> If one is diving a lot, one will find that one can hold one's breath
for
>Pa> three minutes or more. One could thus keep the crown pointed forward
for
>Pa> much of the time while one was submerged.
>
>Pa> > C. Why didn't we look where we were going?
>Pa> >
>Pa> Modern humans can swim in straight lines while keeping their crowns
>Pa> pointed forward. A rather more aquatic ancestor, while not familiar
with
>Pa> geometry, could likely stay headed in the intended direction, perhaps
>Pa> even sneaking a glance while taking a breath.
>
>So you think that for several million years, hominids simply didn't look
>where they were headed...not even to see if they were swimming toward a
>crocodile?
We are getting a little silly aren't we? It seems that your only response
to any argument is to cry crocodile.
>
>Pa> > D. The reduction of hair and its orientation has been said to be
an
>Pa> > adaptation for speed in the water; how did we swim *fast* in this
>Pa> > position?
>
>Pa> Do you know a faster way to swim than modern freestlye?
>
>The position described by examination of our body hair orientation is
>*not* "modern freestyle", or anything like it. At any rate, even modern
>freestyle swum by Olympic athletes is not fast enough to keep out of the
>jaws of aquatic predators.
>
Crying crocodile again.
>Pa> > E. The reduction of hair and its orientation has been said to be
an
>Pa> > adaptation for speed in the water to escape sharks (Hardy 1977,
>Pa> > reprinted 1982); the large land-based predators run approximately
>Pa> > 3-4 times as fast as humans, but sharks swim approximately 3-6
times
>Pa> > as fast as the *fastest Olmpic swimmers*. Why were we able to
swim
>Pa> > away from sharks but not run away from land-based predators?
>
>Pa> I haven't seen that claim about swimming faster to escape sharks
before.
>Pa> Certainly, Morgan has never made it and I couldn't find it in her
>Pa> reprints of Hardy's original talks and articles.
>
>You really *don't* like to read, do you...look again, it's there,
>written by Hardy.
>
>Pa> However, you do miss a vital point when you compare sharks with land-
>Pa> based predator. The aquatic ape only has to get to the shallows to
evade
>Pa> a shark; (sharks are not noted for their wading or running). A
bipedal
>Pa> ape has no such escape route when confronted by a land based
predator,
>Pa> such as leopard, except, perhaps, to dash into the water and dive.
>
>This stupid idea has been dealt with before. I can only call it stupid
>because I've posted many times now information regarding both aqautic
>and land-based predators which refutes it, and you haven't managed to
>read and comprehend it.
>
Sorry. I must have missed your point. Spent too much time swimming in the
open sea in Australia, I suppose, without shark nets or guns to protect
me. Just
like millions of other people around the world. Saw a dolphin once. Swam
over
a few sting rays. Never saw a shark. Not once.
>Pa> >4. Hardy and others say we learned to make sharpened stone tools,
>Pa> > knives, and even spears while in this supposed aquatic phase of
>Pa> > the transition, and to hunt and butcher large animals: why did we
>Pa> > quit doing these extremely useful things for 4-6 million years
>Pa> > after supposedly learning to do so in the water?
>
>Pa> Hardy was writing when anthropologists thought that the man-ape split
>Pa> had occurred considerably earlier than is now believed. The fossil
>Pa> record that is now available to us was not available back in 1960.
>Pa> certainly, Modern proponents of the AAT make no such claims.
>
>It's mentioned in *The Aquatic Ape: Fact or Fiction?* (1991) (along
>with the idea that the aquatic phase was when we got used to cooked
>food!). Morgan also mentioned it in *The Aquatic Ape* (1982). I'm
>always surprised that you apparently don't read, or perhaps just don't
>comprehend, the non- AAT writings on human evolution, but I'm downright
>flabbergasted that you apparently don't even read (or perhaps just don't
>comprehend) the AAT writings!
I quote Hardy:
<<Man no doubt first saw the possibilities of using stones lying ready at
hand on the beach, to crack open the enshelled packages of food....
From the use of such natural stones it was but a step to split flints into
more efficient tools and then into instruments for the chase. Having done
this, and learnt how to make fires, perhaps with dried seaweed on the
sea shore, man now erect and a fast runner was equipped for the conquest
of the continents....While he became a great hunter, we know from the
middens of mesolithic Man that shell fish for long remained a favortite
food.>>
So, as I read it, Hardy has man progressing from using stones to crack
open
shell fish to stone tools for hunting. He segues into the savannah hunter
scenario popular at that time. Sounds reasonable for the time. An outside
observer of some current or recent human cultures might conclude that
humans are still partially aquatic, given their diet and the time they
spend
in the water.
Humans have been killing and butchering every large mammal, terrestrial
or aquatic, that they could get their weapons into, for the past million
years or so. Dugongs would have been the easiest of prey for the post
aquatic ape.
>
>Pa> Whether or not the AAT is true, it is highly likely that early
hominids
>Pa> used
>Pa> stones as tools, for such purposes as cracking open bones for marrow
>Pa> long before true tool making emerged.
>
>This is another false dichotomy: "true tool-making" as opposed to say,
>the types of tool-making seen used by chimpanzees.
True tool making means actually working the stones to create an edge.
Are you claiming wild chimpanzees do this; and that they retain the
products
of this labour for reuse over an extended periuod.
>
>Pa> >5. If we are said, as the AAT does, not to have evolved on land
because
>Pa> > some of our adaptations, such as our method of thermoregulation,
are
>Pa> > different from the methods used by other distantly-related-to-us
>Pa> > mammals in that habitat, such as "the wild ass and the camel",
and
>Pa> > instead supposedly evolved in water and therefore adapted for the
>Pa> > same reasons as aquatic animals, why didn't we adapt by using the
>Pa> same
>Pa> > sort of salt excretion system as marine mammals: extremely large
>Pa> and/or
>Pa> > extremely convoluted kidneys, as in cetaceans and pinnipeds?
>
>Pa> As you suggest, an AA would need a salt excretion system. The AAT
>Pa> suggests that the eccrine glands were adapted for that purpose, along
>Pa> with salt tears ( no other ape sheds salt tears, either). When the
>Pa> aquatic phase ended - perhaps 4 mya when the Sea of Afar became too
>Pa> salty to support a semi-aquatic ape - said ape was forced back to
land.
>
>But the AAT continually says that all animals in an environment will
>evolve the same adaptations (or at least the AAT supporters say that
>when it fits their purposes), so that's why I want you to tell me why
>they didn't do it. Tell me: if it's a fatal flaw to a hypothesis for a
>land-based transition that some of our adaptations, such as our method
>of thermoregulation, are different from the methods used by other
>distantly-related-to-us mammals in that habitat, such as "the wild ass
>and the camel", why isn't it a fatal flaw for the AAT that we didn't
>use our partially pre-adapted kidneys for salt-excretion, as most
>marine mammals do?
The animals that have evolved such salt excretion mechanisms are
100% aquatic with no access to fresh water. A creature that spends a
significant time on land would have access to fresh water. The fact that
there are signs of a salt excretion mechanism in humans but not apes
is significant.
>
>Why do you insist the AAT be accorded special privileges in its
>arguments (this is called, in evolutionary circles, "special pleading")?
Huh?
>
>Pa> >6. If the apparent vitamin A poisoning seen in the "Turkana Boy"
(*Homo
>Pa> > erectus*, KNM-WT-15000) was from eating fish, rather than
carnivore
>Pa> > liver, and was, as Morgan suggests, because we had been doing so
>Pa> > since the transition from apes, why hadn't we either:
>Pa> > A) developed a resistance to such toxic reactions to a food which
>Pa> > supposedly had been eaten regularly for approximately 4-6 million
>Pa> > years before that time?
>Pa> > B) learned how to avoid toxic poisoning from a supposedly common
>Pa> > food?
>Pa> > C) if we had such a resistance and had kept those habits, as
Morgan
>Pa> > suggests, why did we lose the adaptation?
>
>Pa> I think Morgan was wrong in her analysis. Many human cultures survive
on
>Pa> a diet of fish, a rather unusual food source for primates.
>Pa> It's a bit hard to figure out what point you are trying to make,
though.
>Pa> Pat Dooley (PatD...@aol.com)
>
>Although my points are listed extremely clearly, I am not in the least
>surprised that you found it "a bit hard to figure out", given the
>constantly mounting evidence of your lack of reading and comprehension
>of even the sources of the theory you espouse.
This from the person who thinks evolution will proceed quite happily so
long
as the disadvantageous adaptations aren't critical.
Pat Dooley
J. Moore
Cf> There is also
Cf> this phenomenon of crocodile-wrestling; if you can get its mouth closed,
Cf> you can hold it closed bare-handed.
Doesn't do you much good when the jaws are closed around your leg.
Cf> >Pa> 3) The argument that apes could not have adapted to an aquatic
Cf> environment
Cf> >Pa> because of sharks or crocodiles is bogus. Both predators have been
Cf> around
Cf> >Pa> when many other mammal species made the transistion from land to
Cf> water.
Cf> >Pa> The pioneers must have been pretty clumsy in the water during the
Cf> >Pa> initial stages of the transition, but they made it.
Cf> >Pa> Pat Dooley
Cf> >Okay, name them; name some tropical mammals that:
Cf> >A) are about the size of these hominids (or smaller);
Cf> >B) spend 4-8 hours a day in waist-deep or deeper water; and
Cf> >C) reproduce as slowly as humans and chimps.
Cf> Manatee? (I don't know how they reproduce.) Something called
Cf> Dugong(sp?) Otters and various seals deal with sharks.
Cf> -Clara A. N. Fitzgerald cfit...@s.psych.uiuc.edu
Manatee, dugong. Very large animals, as you would have known if you had
done even the slightest attempt at research before posting this. Otters
and seals have young which mature very quickly, which means they replace
their population far quicker than humans or great apes, and otters have
litters of pups, which leads to even quicker population replacement.
Did you even *consider* doing even the slightest research before
posting?
J. Moore
Cf> etc) which you can't see if your eyes are at the surface. You could
Cf> also see fish, patterns of ripples (sharks, etc) and get a sense of the
Cf> currents Please support the opinion that a wider view across land is
Cf> more advantageous than a similar view across water.
JM> I was referring to his claim. At the best of times, the view into clear
JM> water is poor for humans compared to a view through clear.
The line I wrote above should have been "to a view through clear *air*".
J. Moore
Cf> >JM> >Some gorillas, various macaques and the proboscis monkey spend
Cf> >JM> >varying amounts of time in all those places, but show none of the
Cf> >JM> >supposed AAH adatations. They utilise common ape and monkey
Cf> locomotor
Cf> I had heard that probiscus (sp?) monkeys had been picked up by
Cf> fishing boats significant distances from land. You're saying that
Cf> oxygen bell of a nose couldn't possibly have anything to do with
Cf> swimming?
Provide some reference for your statement that the nose of the proboscis
monkey is used as an "oxygen bell". Then explain why this feature isn't
found in females or young. Then explain how the females, without this
feature, swim like the males. I await your detailed reply.
Cf> >JM> >Various environments have been suggested by different AAH
Cf> proponents;
Cf> >JM> >all state that a major reason that these water environments were
Cf> >JM> >necessary for the evolution of bipedalism is to help support the
Cf> body
Cf> >JM> >weight of the animal. Note that this necessarily means that the
Cf> animal
Cf> You've got it backwards; it is suggested that some support for body
Cf> weight was required to allow bipedalism (before anatomical changes had
Cf> occured), and water would perform that function.
Which is what I said. Explain to me how that's "getting it backwards".
Cf> If it was rather easy
Cf> and very beneficial for the ape to stand up, why haven't the chimps or
Cf> baboons tried it?
They do...quite often. You are, I take it, completely unaware of all
the literature on primates?
Cf> >Pa> What are the real advantages of wading compared to quadrupedalism?
Cf> We assume he meant 'bipedal vs. quadrupedal wading', as your reply
Cf> assumes.
No, my reply assumes that he said what he meant: that "wading" is
opposite (to be "compared" with) quadrupedalism. Of course he may
simply be, as you suggest, inarticulate.
Cf> >Pa> 1) Better vision across the surface of the water and back to land.
Cf> >If the water isn't over your head, you can see "back to land" just
Cf> >fine with your head at the surface of the water. On land, however,
Cf> >bipedalism for this purpose would be a huge advantage.
Cf> It it's clear or fairly shallow water, you can see the bottom (rocks,
Cf> etc) which you can't see if your eyes are at the surface. You could
Cf> also see fish, patterns of ripples (sharks, etc) and get a sense of the
Cf> currents Please support the opinion that a wider view across land is
Cf> more advantageous than a similar view across water.
I was referring to his claim. At the best of times, the view into clear
water is poor for humans compared to a view through clear. I would not
say that there are no advantages to your claim (as opposed to his), but
would also point out that Morgan's AAT repeatedly refers to a creature
in water up to its neck ("head-out immersion") which negates your
points completely.
Cf> >Pa> 2) Lower energy usage compared to swimming.
Cf> >Refs, please. I've always found walking through water to be
Cf> >energy-intensive, as water gives such much resistance. But please do
Cf> >provide the references which contradict this impression.
Cf> Consider energy per unit of forward motion. Swimming uses a lot of
Cf> energy moving water around, only some of which also moves the swimmer
Cf> forward.
But please do provide the references which contradict this impression.
Cf> >Perhaps you could explain how the AAT-hominids defended themselves
Cf> >against fierce aquatic predators such as crocodiles and sharks.
Cf> Besides knowing what areas and times to avoid (I would suspect that
Cf> early morning would be fairly safe against crocodiles ???),
Wrong. Very bad time. You have just been eaten...
Cf> it's
Cf> probable there were losses; the birthrate could have made up for them.
Your contention is that the transitional hominids had a birthrate much
higher than that of any of the great apes, or humans? If not, I'm
afraid it's just not enough.
Cf> What's the total yearly loss of lives to shark and crocs?
Cf> -Clara A. N. Fitzgerald cfit...@s.psych.uiuc.edu
As I have pointed out, humans today do not stand around in waist-deep
or deeper water for most of the day, and they have had, for many many
thousands of years, far more effective weapons than even early *Homo
sapiens*, much less the transitional population. In this case, you have
to look for an animal model, as we do in considering the effects of
predators on a land-based transitional population. In the case of an
aquatic population, we have no valid animal model -- ever wonder why?
(Answer: they were all eaten.)
Alex Duncan
patd...@aol.com writes:
> According to the DNA evidence, Chimps and Bonobos are
> our closest relatives, and we are more closely related to them
> than they are to Gorillas. You would never believe that was
> the case based on comparative anatomy.
Have you ever taken an anatomy course? The most astonishing thing about
the anatomy of chimps, gorillas, and humans is how similar they are to
one another. I can think of far more aspects of African hominoid anatomy
in which we are nearly identical to chimps and gorillas than aspects that
are different. As far as humans being more closely related to chimps
than to gorillas -- 1) this notion is controversial, and not as well
supported as you seem to think, and 2) there are a number of
synapomorphies (e.g. early fusion of premaxillary suture) that we share
with chimps and not with gorillas. Are you familiar with the distinction
between apomorphies and plesiomorphies?
> What is even more surprising is the short time frame in which those differences
> emerged. Most of the skeletal transformation occurred in the
> interval between the initial separation from the ape-line, say
> 7.5 mya, and the appearance of fully bipedal Australopithecus,
> say 4 mya.
What exactly do you mean by saying Australopithecus was fully bipedal?
Yes, they were bipeds, WHEN THEY WERE ON THE GROUND (and not in the
trees). However, their bipedalism seems to have differed in some pretty
substantial ways from that of modern humans. Most of the differences
seem to be related to a "compromise anatomy" that enabled terrestrial
bipedalism coupled with tree climbing capacities.
> That is extremely rapid evolution, and could only
> have come about due to a major environmental change; a change
> that somehow seems to have bypassed just about every other
> mammal group in Africa over the same time scale.
How can you say how rapid it is until you've quantified it? To my eyes
the most astonishing thing about the australopithecine skeleton is the
similarity to those of the African apes. Contrary to what you've placed
in other posts, the reorganization of the ape hind limb skeleton to
arrive at an australopithecine hindlimb skeleton is not "major". Fairly
minor changes involving the cranio-caudal length of the pelvis, the
bicondylar angle of the knee, and some details of the foot seem to be the
only real changes that occured. Relatively minor shifts in muscle
placement and size probably accompanied these shifts in skeletal anatomy.
Also, contrary to what you might think, Leakey & Lewin (and Johanson)
are not authorities on functional anatomy. I suggest you read papers by
Stern & Susman and their colleagues.
Finally, this change did not bypass every other mammal group in
Africa. Bovids are arguably among the most successful creatures in
Africa today, and they began their major radiation about the same time we
see evidence for hominid divergence from apes.
Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086
512-471-4206
adu...@mail.utexas.edu
Alex Duncan
patd...@aol.com writes:
>Hominids and modern chimpanzees share a common ancestor from about
>7.5 mya. Gorillas branched off about 2 million years earlier. What you are
>claiming for the ancestral hominds must also be true for chimpanzees and
>gorillas; that their immediate ancestors were as arboreal as modern
>gibbons.
First off, while there are certainly data that support that we and chimps
are each other's closest relatives, the issue is by no means resolved.
Neither are the dates.
Second, why must my claim for pre-hominids also be true for pre-gorillas
and pre-chimps? You seem to be making the assumption that the divergence
event that resulted in hominids also resulted in bipedalism. While this
assumption is widely held, even among paleoanthropologists, it is not
supported by a single scrap of evidence.
<stuff deleted>
> The initial evolutionary imperative would have been to
>minimise exposure on the ground rather than maximise energy efficiency.
>Evolving a whole new mode of locomotion doesn't satisfy that imperative.
>Walking fully upright rather than staying low doesn't satisfy that
>imperative
>either (those who claim that bipedalism makes it easier to spot predators
>should realise that supposed advantage cuts both ways - it also makes it
>much easier to be seen by predators).
Who said anything about evolving a whole new mode of locomotion? I'm
suggesting a gibbon-like ancestor for hominids. Gibbons are so
specialized for arboreality that they are usually bipedal when walking on
the ground. I'm suggesting a similar anatomy for pre-australopiths.
Hominid bipedalism would have involved an elaboration of an already
existing mode of locomotion, rather than the acquisition of a new means
of locomotion.
<stuff deleted>
>It is hard to see how 100% bipedalism, reduced arboreal skills,
>and increased visibility would prove a better strategy in the short-run.
Again, who said 100% bipedalism, or reduced arboreal skills? The
australopith postcranial skeleton indicates substantial arboreal skills.
>>I can think of no oddities that wading and swimming fit in with. Please
>>enlighten me. I'm not suggesting that early hominids didn't occasionally
>>enter the water, but to postulate an aquatic existence as the precursor
>>to all that is "hominid" flies in the face of all of the evidence I'm
>>aware of.
>
>It seems odd to me that humans have aquatic capabilities far greater
>than those of any other apes or primates. Evolution doesn't fill your
>kitbag with capabilities you never use nor ever used. In particular,
>it doesn't equip you with conscious control over your breathing, if
>you don't need it. It doesn't heighten your diving reflexes if you
>don't need it. It doesn't give you a layer of subcutaneous fat if you
>don't need it. It doesn't give you the ability to dive to 250 feet if you
>never dive. It doesn't add salt to your tears and sweat if you never
>needed to exude it. Yet, evolution bestowed all those useless gifts
>on homo sapiens, and all in the last 7.5 million years. Despite having
>98% of their DNA in common with us, chimpanzees share none of those
>features with us. They also missed out on 100% bipedality,
>eccrine sweating, and loss of most of their body hair.
It seems odd to me that we play the piano so much better than the other
apes, and that we manufacture computers, etc. Clearly, there must have
been some advantage to these capabilities among our ancestors (After all,
"music hath charms..."). You are making the mistaken assumption that
every thing we are capable of must be an adaptation. This is ridiculous.
I strongly suggest reading some Gould on this subject (see the article
about the "Panglossian paradigm").
And now, a point by point refutation:
1) The best explanation I've seen for conscious control over breathing
is that it is required for language. There is evidence that human spoken
language skills HAD NOT evolved by the time of KNM-WT 15000. I hope
you're not going to suggest that this individual PRECEEDED our move into
an aquatic environment. Finally, are you quite positive that other
primates aren't capable of conscious control over breathing? Remember,
absence of evidence is not evidence of absence.
2) Diving reflex. OK, I admit, I don't even know what this is. Please
inform me.
3) I assume you think a layer of subcutaneous fat would be advantageous
to living in an aquatic environment. You're right, of course, but it
would only be really advantageous if it were evenly distributed over the
entire body, as is the case for cetaceans. Human fat distribution is far
too uneven to provide a good insulative barrier. And why is fat
distributed differently in males and females? -- and indeed, between
different modern human populations? A more plausible explanation is that
human fat distribution is sexually selected for. We would likely suffer
the greatest heat loss from our distal extremities in an aquatic
environment, and yet fat is most thickly distributed over the proximal
extremities and torso. And finally -- are you sure other primates don't
have subcutaneous fat? I've dissected other primates, and I can state
positively that they do.
4) Dive to 250 feet? Again, I don't have an explanation. But I must
restate a basic tenet of biology that you seem to have never learned: the
fact that we are capable of doing something DOES NOT mean that it is an
adaptation. Again, see Gould.
5) You probably ought to check your references for salt in the tears and
sweat. There has been, and still is, a great tendency for us to assume
that everything we humans do is unique. The more we learn about other
primates, the more we find that this is not true.
Alex Duncan
patd...@aol.com writes:
>You miss the point. I was referring to species, and to the old joke
>about the two safari hunters who, when they were out of ammunition,
>were confonted by a rather hungry lion. Hunter #1 says, "Let's run".
>#2 says, "Why? The lion can run faster than either of us.". #1 replies,
>"Yes, but I can run faster than you." The tottering ape going through
>the transition to exclusive bipedalism would always be #2 - what
>I'd call a "disadvantageous intermediate".
By the same logic, chimps can be called disadvantageous intermediates.
After all, they are by no means the most capable or efficient quadrupeds
in the forest. All terrestrial African carnivores that I can think of
can outrun a chimp. Its a wonder they've survived as long as they have
(sarcasm -- for those of you who don't notice).
I can imagine some day in the future a more intelligent chimp
might evolve, that might have a more efficient mode of quadrupedalism,
and they'll be having these same kinds of arguments. The ignorant among
them will suggest that their ancestors couldn't possibly have functioned
in a forest/mosaic environment as largely terrestrial quadrupeds, because
they clearly weren't as good at it as the other animals. They will claim
that a model of chimp evolution that suggests terrestrial quadrupedalism
combined with arboreal skills couldn't work, because the animal would
have been a "disadvantageous intermediate". They will invent ridiculous
stories to explain aspects of ancestral anatomy that don't seem (to them)
to make sense, and they will adopt dogmatic positions that aren't
supported by comparative anatomy or by examination of living animals.
They will, in fact, ignore any information that doesn't support their
"hypothesis", and cite authorities who don't know any more than they do
to make their points.
I'm reminded of a quote. I don't know the source, but Isaac
Asimov used in one of his books. "Against stupidity, the gods themselves
contend in vain."
Alex Duncan
patd...@aol.com writes:
>There is also the issue of residual webbing in humans. That useless
>flap of skin between your thumb and forefinger is the only thing
>that restricts the movement of your thumb back another thirty degrees
Have you ever heard of the muscle called "adductor pollicis"? I think it
might also have a little to do with the fact that we can't abduct our
thumbs any further than we do. Really, I'm curious: have you ever read
ANYTHING about basic primate or human anatomy?
Your statements remind me of creationism. They all say
"Archaeopteryx is a bird", and within their limited understanding, it is.
Of course, most of them don't know about the presence of teeth, 3
functioning manual digits, absence of a pygostyle, etc. The ones that
don't know about these features are ignorant. The ones that do are
liars. I'll leave it to you to draw the appropriate analogy.
J. Moore
Pa> major skeletal changes that constrain them to 100% bipedalism. (Gibbons
Pa> don't work; they are virtually 100% arboreal and so far off the human
Pa> line as to be irrelevant to the discussion).
As I have pointed out before, it is laughably ludicrous for you or any
AAT-supporter to say that brachiactors such as gibbons are "so far off
the human line as to be irrelevant to the discussion" when *their*
theory depends on comparisons between humans and whales, dolphins, pigs,
hippos (both regular and pygmy), sea gulls, crocodiles, sea snakes and
turtles, seals, sea otters, and "any hairless aqautic mammal", not to
mention (at least somewhat closer to home) Japanese macaques and proboscis
monkeys. Why do you continue to insist that gibbons alone, out of all
the animal world, receive this special "not applicable" treatment?
Pa> >Pa> It's obvious that the last ape to reach
Pa> >Pa> the safety of a tree would be
Pa> >Pa> the first one eaten.
Pa> >
JM> >See how chimps take care of the problem in similar environments.
Pa> You miss the point. I was referring to species, and to the old joke
Pa> about the two safari hunters who, when they were out of ammunition, were
Pa> confonted by a rather hungry lion. Hunter #1 says, "Let's run".
Pa> #2 says, "Why? The lion can run faster than either of us.". #1 replies,
Pa> "Yes, but I can run faster than you." The tottering ape going through
Pa> the transition to exclusive bipedalism would always be #2 - what I'd
Pa> call a "disadvantageous intermediate".
You continue to insist that the only method available to deal with
land-based predators is to run away. If, instead, you'd like to look at
reality, see how chimps take care of the problem in similar environments.
Pa> << yet more nonense about sharks deleted>>
You just *hate* those facts about predators, don't you...
Pa> The point remains; there is no evidence that sharks would have been a
Pa> major predator of semi-bipedal apes frolicking in the shallows.
I do think that they were minor compared to the horrendous problems that
crocodiles would've presented... Among sea otters, only about 10-15%
of the dead each year are due to shark attacks...but then the sharks
are actually after the harbor seals, sea lions, and elephant seals.
That's still "a major predator", but I don't think they would be "*the*
major predator".
Pa> If a semi-bipedal ape being pursued by a leopard tried to escape up a
Pa> tree, I suspect it wouldn't have a hope in hades.
As I have repeatedly shown, a similar animal, the chimpanzee, doesn't
even have a problem with leopards when they're *on the ground* (except
in heavily forested areas). Rather than *suspecting*, you might try
*inspecting*...the literature, that is.
Pa> If a land mammal makes it to
Pa> shore when pursued by a crocodile, it is generally safe. (Just saw
Pa> nature program showing hapless zebras stupidly trying to cross crocodile
Pa> infested waters despite ample evidence that preceding zebras were having
Pa> a little difficult with the crocs. Those that got ashore were not
Pa> pursued, although some lions were waiting to catch the injured).
You must have missed these parts of another post:
pg. 83:
"From this concealed position they can launch themselves out of
the water with astonishing speed, and may make a rush of several meters
up a beach to snap at prey approaching the shoreline. Even large
crocodilians are capable of vaulting almost vertically out of the water
to a height of more then 1.5 meters (5 feet) to snap at birds or animals
on river bancks above them."
pg. 176:
"The final lunge may carry the attacking crocodile several times its
own length up the beach. Acceleration imparted by the powerful tail
is combined with a simultaneous forward swing of the hind legs as the
crocodile beaches. The toes and feet dig into the bank and the powerful
legs lever the body upward. If the bank is steep, the crocodile appears
to vault straight out of the water. If the prey is still out of reach,
the hind-leg stride may be repeated and the crocodile may lower its head
and hook it over the top of the bank to support its body for another
stride. Many an unsuspecting antelope or relaxed fisherman has been
seized in this form of attack, even when 1.5 meters (5 feet) above the
water."
from: 1989 *Crocodiles and Alligators*
Various editors and contributors: Consulting Editor, Charles A. Ross
(Museum Specialist, Department of Vertebrate Zoology, National Museum of
Natural History, Smithsonian Institution, Washington, D.C., USA)
Facts on File: New York and Oxford.
Of course the real problem is your hominid has to make it to shore
first, when crocodiles are generally not detected before they attack,
and once they grab you, they rarely let go.
Pa> On statistical grounds alone we can dismiss the shark threat. Whether or
Pa> not apes marooned on Danakil island had anything to fear from mythical
Pa> African Salt Water crocodiles remains to be seen.
Statistics? You mean like "There are three kinds of lies...lies,
damnable lies, and statistics"? And you're now claiming that Nile
crocodiles are "mythical"... My, what long arms you have...
Pa> The point is that the slightest disadvantage in the short term
Pa> translates into extinction in the long run.
This distinctly non-evolutionary view of life is the notion that "only
perfectly adapted species survive". It wasn't correct when the Sebago
Shoe Company said it in their ad in the *New Yorker*, and it isn't
correct when you say it.
Pa> You obviously don't understand that process or you would not have used
Pa> the phrase "critically disadvantageous" and gone on about surving "long
Pa> enough to raise a few kids".
Pa> Oh dear. I see you believe that evolution will proceed so long as the
Pa> adaptations are not "horribly disadvantageous".
Like it or not, that's how evolution works.
Pa> Since your understanding of evolution is so limited, it
Pa> is obviously pointless to discuss the problem of disadvantageous
Pa> intermediates with you.
Feel free not to. But if you bring up that phony and non-evolutionary
"principle" again, I'll have to point out to you yet again that it
doesn't exist.
JM> >You know, like standing around in crocodile-infested water
JM> >4-8 hours a day would be.
Pa> Now, that's a great example of a strawman argument for you.
Pa> Pat Dooley
The definition of a strawman argument is this:
Strawman Argument: (np) 1. Stating a misrepresented version of an
opponent's argument for the purpose of having an easier target to
knock down.
You have agreed that your purported aquatic ancestors would be standing
or swimming around the water for 4-8 hours a day, and we know that
crocodiles, rather than being "mythical" or "hypothetical" (as some
would have it), are actually very real, large, vicious predators which
have lived in large numbers in all the various habitats that have been
proposed for the putative aquatic hominid. So that wasn't a strawman
argument at all, but instead a real good question.
Any theory of a land-based transition *must* deal with the problem of
predators; why is a theory you espouse to be accorded this special
"no explanations required" treatment?
So maybe you'll be so good as to explain how your purported aquatic
ancestors managed to survive while standing around in
crocodile-infested water 4-8 hours a day.
J. Moore
Pa> I have enough difficulty wading through your posts.
Apology accepted.
Pa> The fact remains that the other species
Pa> I named do wade bipedally. I've even seen them do it on TV.
I've seen them stand and walk bipedally out of water, especially when
carrying things or displaying. Just out of curiousity, and certainly
not because I think you're lying or anything, just when and where on
TV *did* you see bonobos "wading bipedally"? I'd like the title of the
show, with enough information about it so I can see it myself.
Pa> There you go again, misrepresenting a position. All apes can walk on two
Pa> legs to some extent. The proto aquatic ape could certainly have walked
Pa> on two legs without the support of water, just as Macaques, Bonobos and
Pa> Proboscis monkeys do today. The support provided by the water may have
Pa> made it easier for them to maintain that unnatural position.
Please explain how something "unnatural" can be done by all apes and
monkeys. Hint: it isn't "unnatural".
Pa> Pray tell, what sort of sharks and crocodiles infested the ancient salty
Pa> waters of the Afar sea.
Guess you never got around to "wading through" the long posts on
crocodiles and sharks I put together for the benfit of your education.
Pa> If crocodiles were such a prevalent predator of trainee marine mammals,
Pa> as you suggest, then nothing would have made the transition from land to
Pa> water. No Otariidae, no Pinipeds, no Phocids, no Cetacea, no Sirenia, no
Pa> nothing.
I asked you before to name one that's done so that's comparable to
your purported aquatic ancestor:
Name one that's around the size of the common ancestor
(australopithecine/chimpanzee sized), swims as fast as we can (I'll
give them the [unlikely] speed of the fastest Olympic swimmers:
5.1048 mph), spends 4-8 hours a day up in 3-4 feet of water, and
which reproduces as slowly as do chimps and humans who gather/hunt today.
Please, this is the third time I've asked you: name one.
Pa> And if they are such effective predators as you claim, the mere act of
Pa> drinking would have wiped out complete species. A whole panoply of warm
Pa> blooded highly efficient predators roam Africa, but that doesn't mean
Pa> their prey go extinct or stop evolving.
Pa> Your crocodile argument remains bogus.
See above. Name one.
Pa> One of the reasons why I suggested that humans could not have evolved
Pa> bipedalism on the savannah was because of the efficiency of savannah
Pa> predators. You promptly responded by saying they didn't evolve on the
Pa> savannah.
Would you point that out to me? No? Not surprising. I've always said
their most likely environment was the open woodland savannah that existed
in reality at that time, as opposed to *your* "treeless, waterless
savannah" fantasy.
Well, back to the "name one" request:
JM> >Please, I asked you before, but you've not complied: name one.
Pa> The ancestor of the whale was a shoreline scavenger of moderate size. As
Pa> a low slung quadruped, its water speed could not have been great. The
Pa> fossils of this ancient creature were found in the remains of an ancient
Pa> sea that covered northern Pakistan (i.e. warm enough for crocodiles).
You are, I take it, congenitally incapable of providing enough
information to check your claims? No name, no size, no swimming speed,
no reproductive rate info? None at all? You're telling me I have to
leaf through any number of books to study the evolution of whales based
on your unsupported claim? (Given your abysmal track record on the
accuracy of your information so far, I'm not inclined to do so. Give
me some info on it: name, size, estimated swimming speed, estimated
reproductive rate. Tell me where you read it so I can look it up;
that's the way science works.)
At any rate, you'll still be out at sea with that answer, as cetaceans,
as with most mammals actually, have a higher reproductive rate than
chimps and humans who gather/hunt. Oddly enough, even gorillas have a
much higher reproductive rate than chimps and humans who gather/hunt
(about 75% higher). Cetaceans, of course, are also born HUGE and grow
fast, unlike chimps and us. So I'm afraid you'll have to try again with
that naming thing. Next time supply the information requested instead
of just a vague description of a remote possibility of a candidate,
okay?
Pa> But, since you have been so intemperate as to call me nuts, you might
Pa> care to atone by listing the land based ancestors of each and every
Pa> aquatic mammal that would not qualify, due to its large size and/or
Pa> incredible swimming speed, as potential crocodile fodder.
Exactly what possible good do you imagine listing the land-based
ancestors of seals, sea lions, sea otters, etc. etc. etc. would do? We
see by looking at the present that animals with the reproductive
rate of chimpanzees and humans and of the same general size and swimming
speed do not exist in these habitats.
On the other hand, we see by looking at the present that animals with
the reproductive capabilities of chimpanzees and humans and of the same
general size *do* exist in the open woodland savannah habitat.
You're having a real hard time comprehending the significance of this,
aren't you?
JM > 2. Why don't humans have really small ears (or no external ears)
JM > like virtually all aquatic mammals?
Pa> >
Pa> >Pa> The size of external ears in aquatic mammals depends on how aquatic
Pa> >Pa> they
Pa> >Pa> are. Sea lions have residual external ears, as do otters. The AAT
Pa> >Pa> suggests that early hominids became partially adapted to an aquatic
Pa> >Pa> lifestyle; probably not much more than can be seen in some human
Pa> >Pa> cultures today. The time span for the aquatic phase was not long
Pa> >Pa> enough for such features as external ears to disappear.
According to the AAT, it was long enough to reshape our skeletons,
and change the structure of our fat, salt regulation, and hair growth
for all time. Why were ears exempt from these *massive* changes?
Pa> Besides not giving any credence to the principle of non-disadvantageous
Pa> intermediates, you seem to have no interest in the principle of
Pa> convergent evolution, either.
The AAT's views on the power of convergent evolution are *exactly* why
I asked about the ears. Explain to me why ears were exempt from the
effects of convergent evolution as invoked by the AAT.
Pa> We are getting a little silly aren't we? It seems that your only
Pa> response to any argument is to cry crocodile.
Now that you mention it, how *did* we survive standing around in
crocodile-infested water for 4-8 hours a day?
JM> >The position described by examination of our body hair orientation is
JM> >*not* "modern freestyle", or anything like it. At any rate, even
JM> >modern
JM> >freestyle swum by Olympic athletes is not fast enough to keep out of
JM> >the jaws of aquatic predators.
Pa> Crying crocodile again.
Now that you mention it, how *did* we survive standing around in
crocodile-infested water for 4-8 hours a day? You seem to not want
to answer that.
Pa> However, you do miss a vital point when you compare sharks with
Pa> a land-based predator. The aquatic ape only has to get to the
Pa> shallows to evade a shark; (sharks are not noted for their wading
Pa> or running).
You must have missed these quotes:
"The bull shark, *Carcharhinus leucas*, is probably the next most
dangerous shark in warm waters."
"Even though it appears to move slowly when cruising the shallows
inshore, it is capable of fast, agile movements when it wants to
attack prey."
"It frequents shallow water near beaches, and is a versatile and
opportunistic feeder that will attack without provocation."
"It is, therefore, a species that poses a serious threat to
bathers in shallow, warm waters."
From 1989 *Sharks in Question: The Smithsonian Answer Book*
Springer, Victor G. (curator in the Department of Vertebrate Zoology,
Division of Fishes, National Museum of Natural History, Washington,
D.C.), and Joy P. Gold (Technical Information Specialist at the
Department of Vertebrate Zoology, National Museum of Natural History,
Washington, D.C.) Smithsonian Institution Press: Washington, D.C. and
London.
Pa> A bipedal ape has no such escape route when confronted by a land based
Pa> predator,
Pa> such as leopard, except, perhaps, to dash into the water and dive.
Or to handle the matter as our closest relatives, the chimpanzees of the
open woodland savannah, do.
J. Moore
JM> knives, and even spears while in this supposed aquatic phase of
JM> the transition, and to hunt and butcher large animals: why did
JM> we quit doing these extremely useful things for 4-6 million years
JM> after supposedly learning to do so in the water?
Pa> >
Pa> >Pa> certainly, Modern proponents of the AAT make no such claims.
Pa> >
Pa> It's mentioned in *The Aquatic Ape: Fact or Fiction?* (1991) (along
Pa> with the idea that the aquatic phase was when we got used to cooked
Pa> food!). Morgan also mentioned it in *The Aquatic Ape* (1982). I'm
Pa> always surprised that you apparently don't read, or perhaps just don't
Pa> comprehend, the non- AAT writings on human evolution, but I'm downright
Pa> flabbergasted that you apparently don't even read (or perhaps just
Pa> don't comprehend) the AAT writings!
Pa> I quote Hardy: <deleted>
Pa> Humans have been killing and butchering every large mammal, terrestrial
Pa> or aquatic, that they could get their weapons into, for the past million
Pa> years or so. Dugongs would have been the easiest of prey for the post
Pa> aquatic ape.
I repeat the question then. Since the divergence, which supposedly was
this aquatic phase which included hunting and butchering large animals,
was 4-6 million years before there is any evidence of sharp tools, or
butchering or hunting of large animals:
why did we quit doing these extremely useful things for 4-6 million years
after supposedly learning to do so in the water? Why did we stop using
these extremely useful sharp cutting tools for 4-6 million years
after supposedly learning to do so in the water?
JM> This is another false dichotomy: "true tool-making" as opposed to say,
JM> the types of tool-making seen used by chimpanzees.
Pa> True tool making means actually working the stones to create an edge.
Pa> Are you claiming wild chimpanzees do this; and that they retain the
Pa> products of this labour for reuse over an extended periuod.
Pat, you can't Humpty Dumpty the field of paleoanthropology to suit your
own whims; "true tool making" means "really making tools". If you want
to restrict the discussion to worked and sharpened stone tools, you say
"worked and sharpened stone tools", not "true tool making". Like it or
not, chimps make tools, truly.
(The Humpty Dumpty reference, for those who don't know it, is from
*Through the Looking Glass*: "When *I* use a word," Humpty Dumpty said
in rather a scornful tone, "it means just what I choose it to mean --
neither more nor less.")
Pa> The animals that have evolved such salt excretion mechanisms are 100%
Pa> aquatic with no access to fresh water. A creature that spends a
Pa> significant time on land would have access to fresh water. The fact that
Pa> there are signs of a salt excretion mechanism in humans but not apes is
Pa> significant.
Oh Pat, this is just plain pitiful. Haven't you considered *ever*
reading and learning? I mean... someday? Your first sentence is
categorically wrong. Period. No question mark. Your third sentence is
equally telling. In fact there *is* a salt excretion mechanism in *all*
mammals. True, there are uncontrolled, and hence ineffective, ones such
as tears and sweat in many mammals, but the regulated, effective mechanism
is via the kidneys. This is why marine mammals (like cetaceans, seals,
and sea otters) evolve large, heavily lobulated kidneys. It's *the*
mammalian way to control salt and water balance in a regulated manner,
which is a necessary function for all mammals, as it is for virtually
all vertebrates, although some use different organs for this purpose
than do mammals.
Doesn't the constant exposure of your ignorance bother you?
JM> >Why do you insist the AAT be accorded special privileges in its
JM> >arguments (this is called, in evolutionary circles, "special
JM> pleading")?
Pa> Huh?
Well, this time I must say your reply speaks for itself.
Pa> It's a bit hard to figure out what point you are trying to make,
Pa> though.
Pa> Pat Dooley (PatD...@aol.com)
JM> >Although my points are listed extremely clearly, I am not in the least
JM> >surprised that you found it "a bit hard to figure out", given the
JM> >constantly mounting evidence of your lack of reading and comprehension
JM> >of even the sources of the theory you espouse.
Pa> This from the person who thinks evolution will proceed quite happily so
Pa> long as the disadvantageous adaptations aren't critical.
Pa> Pat Dooley
Well, I do think that, just as do all reasonably knowledgeable people
with even the vaguest grasp of evolutionary theory.
I know you don't understand the rather obvious problem inherent in your
view, but I've ceased being surprised at that.
Alex Duncan
cfit...@s.psych.uiuc.edu writes:
>-Clara A. N. Fitzgerald cfit...@s.psych.uiuc.edu
> - < - < -< <> >- > - > -
>Help stamp out, reduce, and eliminate redundancy.
Let's get rid of repetition while we're at it.
Pat Dooley
>From: her...@gmu.edu (Harry Erwin)
I wrote:
>> The upper limit on unassisted human diving performance
>> is about 250 feet. Some human groups regularly dive to a depth of 80
>> feet. These aren't just learned capabilities - there are physiological
>> adaptations to support them, including conscious control over
>> breathing, a heightened diving reflex that slows the heart rate
>> down from 72 to 35 beats per minute, and an ability to hold ones
>> breath for 3 minutes or more.
>
>These are features that could have been acquired fairly late, especially
>since they are nervous system adaptations, an area where biological
>innovations are known to be particularly easy. Fixation would have taken
>no more than 1000 generations. My suspicion is that the connection of the
>emergence of modern man with the appearence of sea-going cultures might
be
>related.
The human diving reflex is more than a simple nervous system adaptation.
For example, in simulated deep dives under laboratory conditions it was
found that the circulation to the limbs was completely shut down and
the heart rate slowed to about 12 beats per minute.
Other unique adaptations that facilitate human diving include:
1 .Hairlessness ( to reduce drag on descent and ascent)
2. Downward pointing nostrils (that stops water from being forced into the
nasal cavaties)
3. Descended larynx
4. Bipedalism (keeps legs, spine and head in one plane)
It's a sign of progress when you are forced to admit the existence of
biological
innovations that seem to support diving. However, your suspicion that the
"emergence of modern man with the appearence of sea-going cultures might
be
related" has some major difficulties. It implies that identical
adaptations arose
amongst unrelated cultures, (extremely unlikely), or that we are all
descended
from a single, modern sea-going culture. That, too, seems unlikely.
Your 1000 generations figure is also suspect. Aborigines have lived in
Australia for upwards of 50,000 years (3000-3500 generations) isolated
from the rest of humanity yet they show no signs of any special nervous
adaptations, despite a small population base, and a unique environment;
i.e. a situation where you might expect some evolutionary changes to
occur fairly rapidly.
>
>>
>> Such features would not be surprising if our closest relatives
>> could achieve some significant fraction of these capabilities.
>> But, there is no sign of such capabilities in them or in other
>> fully terrestrial mammals.
>>
>> It can also be argued that human limbs are partially adapted for
>> swimming and diving. In particular, a human being can swim or dive with
>> their arms, legs, head and body in a plane. That improves efficiency
>> and is a feature of most semi-aquatic and aquatic mammals.
>
>Ah! I see your argument. Unfortunately, those features are also useful
for
>arboreal movement of small apes.
>
Not unfortunately, at all. It provides a better starting point than a
quadrupedal gait.
>>
>> There is also the issue of residual webbing in humans. That useless
>> flap of skin between your thumb and forefinger is the only thing
>> that restricts the movement of your thumb back another thirty degrees;
>> other apes don't have such a flap. A significant percentage of humans
>> still have further vestigal webbing between their fingers and toes.
>
>The thumb/first-finger web is the primary path by which large external
>forces are coupled to the hand structure in man. In the apes, the thumb
is
>reduced or (in the gibbons) adapted to swing out of the way and the
forces
>are transmitted via the fingers, which are vulnerable to breakage and
>other injury and so must be fairly tough and indelicate. Yes, the web
>restricts thumb mobility, but it allows the thumb and fingers to be
>delicate manipulatory appendages with a reduced risk of damage.
>
What the web does now does not necessarily explain why it evolved.
You also skipped the issue of vestigal webbing.
>--
>Harry Erwin
Pat Dooley
Pat Dooley
>
>In article <3t7ar6$7...@newsbf02.news.aol.com> Pat Dooley,
>patd...@aol.com writes:
>
>> According to the DNA evidence, Chimps and Bonobos are
>> our closest relatives, and we are more closely related to them
>> than they are to Gorillas. You would never believe that was
>> the case based on comparative anatomy.
>
>Have you ever taken an anatomy course?
No.
>The most astonishing thing about the anatomy of chimps,
>gorillas, and humans is how similar they are to
>one another. I can think of far more aspects of African hominoid anatomy
>in which we are nearly identical to chimps and gorillas than aspects that
>are different.
Well, you'd expect them to be pretty similar, given the degree of
relationship. In fact you'd expect them to be as similar as, say,
horses and the various zebra species. But simple observation tells
you there are major differences.
(i) Hairlessness
(ii) Bipedalism and the host of skeletal differences that come with
100% bipedalism.
(iii) The relative position of the larynx
(iv) Subcutaneous fat layer (Have you ever done a comparative
dissection of the various species under discussion)
(v) Downward pointing nostrils
(vi) Cooling mechanisms
(vii) Loss of oestrus in human females
(viii) Different structures for supplying blood to the brain
(ix) Radically different degree of adaptability to aquatic environments
I'd be more impressed with your statement of how similar we are
to apes if you could give some other examples of closely related
species that have more radical differences than there are between
humans and apes.
>As far as humans being more closely related to chimps
>than to gorillas -- 1) this notion is controversial, and not as well
>supported as you seem to think, and 2) there are a number of
>synapomorphies (e.g. early fusion of premaxillary suture) that we share
>with chimps and not with gorillas.
2) contradicts 1), Does it not?
>Are you familiar with the distinction between apomorphies and
plesiomorphies?
No.
I have not had the advantage of an anatomy course
>
>> What is even more surprising is the short time frame in which those
differences
>> emerged. Most of the skeletal transformation occurred in the
>> interval between the initial separation from the ape-line, say
>> 7.5 mya, and the appearance of fully bipedal Australopithecus,
>> say 4 mya.
>
>What exactly do you mean by saying Australopithecus was fully bipedal?
>Yes, they were bipeds, WHEN THEY WERE ON THE GROUND (and not in the
>trees). However, their bipedalism seems to have differed in some pretty
>substantial ways from that of modern humans. Most of the differences
>seem to be related to a "compromise anatomy" that enabled terrestrial
>bipedalism coupled with tree climbing capacities.
I just reread the section in Lucy's Child pages 194ff discussing this very
issue. Seems to be a point of contention as to the degree of bipedalism
versus arborealism displayed by Afarensis.
>> That is extremely rapid evolution, and could only
>> have come about due to a major environmental change; a change
>> that somehow seems to have bypassed just about every other
>> mammal group in Africa over the same time scale.
>
>How can you say how rapid it is until you've quantified it? To my eyes
>the most astonishing thing about the australopithecine skeleton is the
>similarity to those of the African apes. Contrary to what you've placed
>in other posts, the reorganization of the ape hind limb skeleton to
>arrive at an australopithecine hindlimb skeleton is not "major". Fairly
>minor changes involving the cranio-caudal length of the pelvis, the
>bicondylar angle of the knee, and some details of the foot seem to be the
>only real changes that occured. Relatively minor shifts in muscle
>placement and size probably accompanied these shifts in skeletal anatomy.
> Also, contrary to what you might think, Leakey & Lewin (and Johanson)
>are not authorities on functional anatomy. I suggest you read papers by
>Stern & Susman and their colleagues.
Page 200 of Lucy's Child shows Owen Lovejoy's reconstruction of Lucy's
pelvis compared to a human pelvis and a chimpanzee. What you desribe
as minor looks pretty major to my untrained eye. The chimpanzee pelvis
stands out as startlingly different.
Is there a little tension between L,L,L & J and S & S? It's pretty obvious
which side you are on.
> Finally, this change did not bypass every other mammal group in
>Africa. Bovids are arguably among the most successful creatures in
>Africa today, and they began their major radiation about the same time we
>see evidence for hominid divergence from apes.
>
>Alex Duncan
So, name three bovid species as closely related as humans, chimps and
gorillas, in genetic terms, yet just as different physically.
Pat Dooley
Pat Dooley
<< Deletions>>
> That sort of tells us that apes usually have
>dealt with water by staying out of it.
>
>Now the major problem with the aquatic ape hypothesis is that it involves
>two sequential adaptive stages, each rather major in a behavioral sense,
>the first into the water and the second out of it, within the period 7-4
>MYr BP.
The first stage - into the water - took up most of the 7-4 Myr BP. The
end result of that period is a fully bipedal ape partially adapted for
an aquatic existence.
The second stage covers the last 4 million years when humans
became fully adapted for a terrestrial environment. The non-harmful
aquatic adaptations remain with us.
>We do have some data on rates of evolution. Generally, a primate
>species lasts about 1 MYr, so we're talking about three species worth of
>evolution. Now evolution does go faster, but in the context of an
>explosive radiation (no evidence) or an externally applied selective
>gradient.
The first stage roughly corresponds to the geological evidence for
the Sea of Afar. What sort of selective gradient would the sudden
formation of a large sea impose on those creatures trapped on islands
in that new sea? Fairly drastic, one would think.
>In the latter case, you get fixation in perhaps 1000 generations
>as the natural variation in the gene pool (better be good sized!) is used
>up, so the initial impetus would not have continued for a significant
>portion of the 3 MYr.
Assuming, of course, that the initial impetus didn't continue. But
the trapped populations would have been under continued evolutionary
pressure as, firstly, the forests on the islands dried out, and secondly,
the
Sea of Afar gradually dried out.
>Instead, evolution after the first 1000 generations
>would have been dependent on the usual evolutionary processes at the
usual
>rates. Also, the rate of evolution could have been expected to regress
>towards the mean, so we're talking of perhaps 4 species in 3 MYr. That's
>probably enough to evolve bipedality in a small African ape, but hardly
>enough to take it out to sea and return.
>
Adaptations do not necessarily evolve in sequence. If there was time
enough
for a major change like bipedalism, there was certainly enough time for
the
rest of the AAT adaptions to evolve in parallel, particularly if, as would
be
the case in an aquatic scenario, the adaptations were complementary.
>
>I think that's the gist of what would be the average anthropologist's
take
>on the subject.
I'll believe 'em when they dig up the fossils to prove humans evolved far
away from any sea shore. The fossil gap is still there but the plugging
seems to be drifting closer to the ancient Sea of Afar.
Pat Dooley
Pat Dooley
>What about this:
>
>Organisms that spend much of their time in (at least) chestdeep
>water will be selected to make use of Archimedean Law in an
>efficient way.I think that is by floating and/or swimming,not by
>walking upright.Walking upright is not an efficient way of getting
>around in chestdeep water.
It is efficient in shallow water, especially when you are looking
for shellfish and the like.
Human swimming is more efficient that quadruped swimming
precisely because bipedalism puts the body into a single plane.
(Even seen a chimp swim?)
>It is not the right environment to select in favour of an anatomical
>complex that suits bipedal locomotion because the upward pressure
>of the water takes much of the load of the body off your lumbar spine,
>pelvis and lower limbs.That load is exactly what is needed to remodel
>the anatomical complex of an arboreal ape into that of a bipedal ape
>that walks on land.
You assume that the AAT claims bipedalism is an adaptation for
chest deep wading. I think it was more likely an adaptation that
suited shallow water wading and swimming.
Lucy, the first nearly complete skeleton of an Australopithecus
afarensis, had feet that were broader and larger than ours,
(35% of leg length instead of 26%). Her gait was described by
Roger Lewin as "not quite as bad as trying to walk on dry land
wearing swimming flippers but in the same direction."
Post Lucy, the major bipedal adaptations were longer legs, smaller feet,
and locking knees.
>Without those gravitational forces there is no selection to remodel the
>lower body in favour of bipedalism.Instead you would expect a kind
>of "degeneracy" or remodeling in the direction of wateradapted
>locomotion.(i.e swimming and/or floating).
Compared to other primates, it may well be that bipedalism is
a partial adaptation for swimming, along with hairlessness
and a subcutaneous fat layer.
>Other mammals that have moved to the water have lost their hindlimbs
>altogether as in whales,dolphins and manatees or they have
>become much less functional in terrestrial locomotion as is the case
>in pinnipeds,and where they kept their legs they became adapted to
>swimming as in otters(webbed feet).
But none of these animals fill a niche that combines swimming and diving
combined with shallow water and shoreline foraging. The massive shell
middens left by many early human cultures attest to continued ability to
fill that niche.
>On these grounds I think it is unlikely that an anatomical change in
>the direction of bipedalism (on land) will begin to develop in an aquatic
>environment as proposed in the AAT.
>
>Gerrit
Redo your analysis using shallow water wading, and swimming, and start
with a semi-arboreal ape partially adapted to bipedalism.
Pat Dooley
Pat Dooley
Alex Duncan <adu...@mail.utexas.edu> writes:
>patd...@aol.com writes:
>
>>You miss the point. I was referring to species, and to the old joke
>>about the two safari hunters who, when they were out of ammunition,
>>were confonted by a rather hungry lion. Hunter #1 says, "Let's run".
>>#2 says, "Why? The lion can run faster than either of us.". #1 replies,
>>"Yes, but I can run faster than you." The tottering ape going through
>>the transition to exclusive bipedalism would always be #2 - what
>>I'd call a "disadvantageous intermediate".
>
>By the same logic, chimps can be called disadvantageous intermediates.
>
I don't follow your logic. Chimps evolved. Disadvantageous intermediates
don't.
Up until the introduction of the gibbon like precursor, the debate had
focused
on a quadrupedal ape evolving into a bipedal ape. In that context, one has
to
ask about the intermediate forms between the quadrupedal knuckle walker
and our bipedal ancestor.
Now we are being told that bipedalism resulted from the movement of
an arboreal ape directly to a terrestrial environment. That may well be
true.
But the scenario painted so far has a gibbon like ape of about gibbon
size making the transition. That seems to me to be a very vulnerable
creature to go prancing about between clumps of forest. The predators
of 7.5 mybp were not notably less ferocious nor less effective than
present
day predators.
Perhaps it might be better to ignore human evolution for a while and
focus on chimpanzee evolution. When did knuckle walking evolve?
What does the fossil record tell us about chimpanzee evolution?
Was it gradual or were there periods of rapid evolution? Does anyone
out there know anything about chimpanzee evolution?
>
>
>After all, they are by no means the most capable or efficient quadrupeds
>in the forest. All terrestrial African carnivores that I can think of
>can outrun a chimp. Its a wonder they've survived as long as they have
>(sarcasm -- for those of you who don't notice).
They did survive, so we don't have to speculate on how that happened.
Your sarcasm does raise an interesting issue, though. Ignoring the
special case of humans, apes have been relatively less successful than
monkeys over the last 15 million years. The number of species has
declined drastically, whereas monkeys have proliferated. In the time
scale of evolution, it might prove that you spoke too soon when
claiming success for chimpanzees.
> I can imagine some day in the future a more intelligent chimp
>might evolve, that might have a more efficient mode of quadrupedalism,
>and they'll be having these same kinds of arguments. The ignorant among
>them will suggest that their ancestors couldn't possibly have functioned
>in a forest/mosaic environment as largely terrestrial quadrupeds, because
>they clearly weren't as good at it as the other animals. They will claim
>that a model of chimp evolution that suggests terrestrial quadrupedalism
>combined with arboreal skills couldn't work, because the animal would
>have been a "disadvantageous intermediate". They will invent ridiculous
>stories to explain aspects of ancestral anatomy that don't seem (to them)
>to make sense, and they will adopt dogmatic positions that aren't
>supported by comparative anatomy or by examination of living animals.
Cute. But if your future chimp is 100% bipedal she would clearly be
entitled
to ask how the ancestral chimp went from quadrupedalism to bipedalism
without disadvantageous intermediates; i.e. forms that were less efficient
quadrupeds because of their bipedal tendencies, but were not yet efficient
bipeds; what I call the tottering ape problem.
Take the example of flight. So far as I know, flying animals, be they
birds
or mammals, evolved from arboreal ancestors. Even today, we can see
intermediate examples such as the flying squirrel, and its cousin by
convergent evolution, the marsupial sugar glider. Clearly, the
intermediate
forms aren't disadvantageous. Every slight improvement in gliding ability
is better than the slight loss in arboreal mobility.
Whenever somebody proposes a scenario for the evolution of bipedalism,
I like to see if it provides an advantage to the organism at each stage,
in the proposed environment.
If it can't satisfy that test, then I don't believe it could have evolved
that way.
>They will, in fact, ignore any information that doesn't support their
>"hypothesis", and cite authorities who don't know any more than they do
>to make their points.
The AAT supporters have clearly had to modify their position as new
evidence comes to light. The orthodox position has had to make even
greater modifications, particularly since the discovery of Lucy (even if
she isn't on the direct line of descent).
In Scars, Elaine Morgan cites a wide range of respected authorities. Some,
like Pond, would rather she didn't.
> I'm reminded of a quote. I don't know the source, but Isaac
>Asimov used in one of his books. "Against stupidity, the gods themselves
>contend in vain."
Asimov has turned out to be stupid on at least one count completely
irrelevant
to this discussion.
The issue the AAT proponents do not ever address, except with vague
mutterings about "hitch hiker" genes and learned skills, is human aquatic
capabilities. They didn't evolve for no reason and they don't show up in
our closest relatives. Do chimps dive? No. Do gorillas swim? No. If you
put a gorilla in a water filled pressure chamber and simulate a diving
depth
of 250 feet, does its heart rate slow down dramatically? Who knows - the
gorilla couldn't hold its breath long enough for you to find out. If a
chimp
dived head first into a river, would water be forced into its nasal
cavities?
Almost certainly. etc. etc.
Admittedly humans learn some of their aquatic skills. But it turns out
they can
learn to swim before they can learn to walk. It is also the case that the
human
diving reflex isn't learned. Divers don't consciously reduce their heart
rates
and cut off blood flow to their limbs when they dive deeply. (I just saw a
program on TLC exploring human diving performance in some depth (pun); the
program was unrelated to the AAT. The reduction in heart rate and the
extent
to which the blood supply was localised to serve the brain at the expense
of the rest of the body was quite amazing. Would you believe 12 beats
per minute? Anybody else see that program?)
Some people have claimed that these adaptations are relatively recently.
But the fossil record for the past million years or so is relatively
complete
and doesn't show much relationship with aquatic environments.
So, before you call us stupid again, please explain these aquatic
adaptations
in clear evolutionary terms. Conversely, you could cite papers showing
that chimpanzees, gorillas, bonobos, and even gibbons have aquatic
abilities within a standard deviation or two, of the present human norm.
>
>Alex Duncan
Pat Dooley
Mark Cipra
says...
>
> I'm reminded of a quote. I don't know the source, but Isaac
>Asimov used in one of his books. "Against stupidity, the gods
themselves
>contend in vain."
Schiller, I believe
J. Moore
Pa> size making the transition.
I haven't seen the "about gibbon size" creature mentioned; rather the
constant refrain, which you nevertheless seem to have missed, is a
transitional hominid about the size of a chimpanzee.
Pa> The predators of 7.5 mybp were not notably less ferocious nor
Pa> less effective than present day predators.
No, those crocodiles were horrific, just as today...whoops, I forgot,
you're trying real hard to ignore *them*. I'm sorry I reminded you. As
for the land-based predators, we can see that open woodland savannah
chimps handle them fine, and feel that a transitional hominid which was
much the same size, although possibly somewhat smarter, could've done
the same.
But, it just occurred to me: how did your purported aquatic ancestors
survive standing around for 4-8 hours a day in crocodile-infested water?
Pa> Your sarcasm does raise an interesting issue, though. Ignoring the
Pa> special case of humans,
Why do you insist on ignoring them here? We continue:
Pa> apes have been relatively less successful than
Pa> monkeys over the last 15 million years. The number of species has
Pa> declined drastically, whereas monkeys have proliferated.
Humans have proliferated...which is why you wanted to ignore them.
However, you are also making an unsupported claim here, *and* using a
false dichotomy, or confusion of logical types. On the one hand, you
talk about "number of species declined drastically", whereas on the
other hand you say that numbers of individual monkeys "have
proliferated". Of ocurse it wouldn't help your overall argument to use
consistent logic since your facts are so often wrong, but it would help
keep you from looking such a fool.
Pa> In the time scale of evolution, it might prove that you spoke
Pa> too soon when claiming success for chimpanzees.
They are successful in evolutionary terms, since they survived. That is
the definition of evolutionary success. But I suppose it is likely that
if they had just increased their quotient of bipedal behavior, instead
of going the other direction into increased quadrupedal behavior, when
we, their cousins, did, they might've been more numerous today.
In fact, they'd be *us*. Bad luck, fellas.
Pa> In Scars, Elaine Morgan cites a wide range of respected authorities.
Pa> Some, like Pond, would rather she didn't.
Pa> Pat Dooley
I've never seen Pond say she "would rather she didn't". Please provide
your source for this claim. On the other hand, I *have* seen Pond
produce articles showing that human fat distribution and properties
do not meet the requirements of the AAT, which Morgan has ignored.
HARRY R. ERWIN
Simons in Primate Evolution, MacMillan, 1972, p 236, indicates
knuckle-walking "is easily derived from arboreal quadrupedalism where both
wrist and elbow joints have developed locking flanges on certain joints,
together with robust phalanges adapted to supporting the compressive
forces produced by the weight of a comparatively larger forebody." The
Miocene ancestors of the modern African apes were rather gracial, even in
those forms with limb lengths comparable with modern chimpanzees.
--
Harry Erwin
Internet: her...@gmu.edu
Home Page: http://osf1.gmu.edu/~herwin (try a couple of times)
John Wilkins
<adu...@mail.utexas.edu> wrote:
: In article <3t9mfd$9...@vixen.cso.uiuc.edu> Clara N. Fitzgerald,
: cfit...@s.psych.uiuc.edu writes:
:
: >-Clara A. N. Fitzgerald cfit...@s.psych.uiuc.edu
: > - < - < -< <> >- > - > -
: >Help stamp out, reduce, and eliminate redundancy.
:
: Let's get rid of repetition while we're at it.
:
Not to mention pleonastic tautologies...
--
John "Chris" Wilkins, Assoc. Prof. of Recent Runes, Uni of Ediacara
Also: Head of Communication Services, Walter and Eliza Hall Institute
Home Page: http://www.wehi.edu.au/~wilkins/www.html
I'd be willing to argue that point (said the arachnid to the dipteran) - Chris Colby on talk.origins
Phil Nicholls
>Re: Bipedalism and other factors
>>From: her...@gmu.edu (Harry Erwin)
>
>I wrote:
> >> The upper limit on unassisted human diving performance
>>> is about 250 feet. Some human groups regularly dive to a depth of 80
>>> feet. These aren't just learned capabilities - there are physiological
>>> adaptations to support them, including conscious control over
>>> breathing, a heightened diving reflex that slows the heart rate
>>> down from 72 to 35 beats per minute, and an ability to hold ones
>>> breath for 3 minutes or more.
>>
>>These are features that could have been acquired fairly late, especially
>>since they are nervous system adaptations, an area where biological
>>innovations are known to be particularly easy. Fixation would have taken
>>no more than 1000 generations. My suspicion is that the connection of the
>>emergence of modern man with the appearence of sea-going cultures might
>be
>>related.
>The human diving reflex is more than a simple nervous system adaptation.
>For example, in simulated deep dives under laboratory conditions it was
>found that the circulation to the limbs was completely shut down and
>the heart rate slowed to about 12 beats per minute.
As has been posted several times before, the "human" diving reflex is
also present in dogs and any other mammal that you can train to dive
and thus remove the fear such an activity would otherwise entail.
Check "Aquatic Ape: Fact or Fiction."
>Other unique adaptations that facilitate human diving include:
>1 .Hairlessness ( to reduce drag on descent and ascent)
I believe there are studies that show that it actually makes no
difference.
>2. Downward pointing nostrils (that stops water from being forced into the
>nasal cavaties)
The direction of human nostrils is a result of (a) being catarrhine
primates and (b) lose of facial prognathism. Early hominids did not
have noses like ours.
>3. Descended larynx
The neandertal larynx is only partially descended compared to our own.
More importantly, newborn infants do not have a descended larynx.
>4. Bipedalism (keeps legs, spine and head in one plane)
There are no aquatic bipeds.
==========================================================
Phil Nicholls "To ask a question you must first
pn...@globalone.net know most of the answer.
Semper Alouatta! - Robert Sheckley
Elaine Morgan
requirements of the AAT, which Morgan has ignored."
Please give me the reference for these articles. I have seen
indications that Pond does not agree with AAT or wish to be associated
with it. I
have not seen any article in which she produces evidence that would
disprove it. I would be grateful if you could tell me where to find
this evidence. Sometimes I am able to answer such arguments and
sometimes I have to admit "I got this bit wrong", but I have never to
my knowledge dealt with a counter-argument by
deliberately "ignoring" it
Elaine Morgan
Elaine Morgan
J.D. Moore asks where did anybody see a film of bonobos wading
bipedally? I personally made a video film about AAT which included
two or three shots of them doing just that, and a couple os shots of
them walking upright on land in the forest, one behind
the other. I was allowed to use those shots on condition the film was
not shown commercially, only for e.g.seminars. I showed it once in San
Francisco. Copies for US video are available (can I say this? I am
assured that the charge is no more than enough to cover reproduction
and postage) from Ralph Metzner, 18210 Robin Avenue, Sonoma, CA
95476. I get nothing, okay?
J. Rhiemeier writes:
"Australopthecus did walk upright, no doubt. But it neither had
downward facing nostrils, and it was almost as hairy as a chimpanzee.
Okay, let's talk nostrils. There is no evidence whether it did or did
not have downward facing ones. As we see in the proboscis monkey, a
downwrd projection in the fleshy part can precede - or exist without -
any change in the skull. (Female and young proboscis have it too,
though far less pronounced). By the time of erectus an actual nasal
spine had evolved. (I had thought it earlier, this was what I was wrong
about as I am frequently reminded). This ossified nasal spine was most
probably a consolidation of a previous more perishable cartilaginous
version, comparable with the septum in modern Homo. It suggests that
something unusual had been happening to the nose for quite a long time;
in erectus's day it had been established long enough to need a skeletal
structure to underwrite it. If elephants were extinct and we could only
reconstruct them from the bones of the skull, who would be clever
enough to know what a trunk looked like?
And how can you say that austropiths were nearly as hairy as a chimp? A
purely arbitrary assertion. You would like to think they were.
Re Tattersall: I do not believe that the shape of the skull can tell us
anything about the respiratory canal. The pharyngeal space was enlarged
not by altering the shape of the skull but by the larynx sliding down
to below the back of the tongue.
Tears, idle tears... If anyone can find an ape that weeps from grief, I
will eat my computer. The innervation is totally different..
Rates of evolution. These are not hard figures. It is fairly meningless
to say one million years is three species' worth of evolution, because
even the term species is a man-made convenience. There is no place you
can draw a line between one species and its successor. Sombody (it may
have been Haldane?) invented the term "darwin" to measure how fast a
species evolved, but it has never come into use. When an animal evolves
too many things change simultaneously, there is no agreement about
which are the most important ones and no way of quantifying the net
result.
We can only say we have the impression that since 7mya the homo line
has moved further away from the l.c.a. than the apes have done. i.e.
our anncestors developed faster. Two factors are known to favour rapid
spciation (1) geographic isolation, absolute enough to preclude
interbreeding - (2) a sudden marked change in the habitat. Compare AAT
and savannah mosaic. Which best accounts for (1)? Which best accounts
for (2)? Yes, I've heard of sympatric speciation - a very rare event
though compared to being cut off, as the Congo cut the chimps off from
the bonobo.
Elaaine Morgan
David L Burkhead
[ 8< ]
>
>Tears, idle tears... If anyone can find an ape that weeps from grief, I
>will eat my computer. The innervation is totally different..
>
If you will show me an aquatic mammal that weeps from grief, _I_
will eat your computer. Just make sure you use the _same_ standards
of proof that you would use for primates.
"Different from other primates" even if it holds up, is not
automatically "support for the aquatic ape hypothesis." And any
attempt to make anything out of humans being the only primate, or the
only animal to spend a large part of its evolutionary history on the
savannah, or the only whatever else to take a particular tack, leaves
yourself _wide_ open to objections about, in your hypothesis, humans
then become "the only aquatic animal" to take a number of tacks--like
bipedalism. I'm still waiting for a citation of even _one_ animal
that took up bipedalism as a result of an aquatic lifestyle.
David L. Burkhead
r3d...@dax.cc.uakron.edu
d.bur...@genie.geis.com
--
Spacecub - The Artemis Project - Artemis Magazine
Box 831
Akron, OH 44309-0831
Ed Haynes
Gh> they would naturally encounter. (My source is Elaine Morgan's work.
Gh> haven't checked her citations on this issue).
Gh> Check her citations and give me some of her references.
JM>You'll be waiting a long long time.
JM>She gives none. None whatsoever. (The statement is from *The Scars of
JM>Evolution* [1990].)
According to Richard Milner's THE ENCYCLOPEDIA OF EVOLUTION p22, Elaine
Morgan is a Welsh writer and on p128 she "challenged the male-oriented view
of evolution and offered a feminist corrective" in her book, THE DESCENT OF
WOMAN.
---
* WR 1.33 # 24 * InterNet: ed.h...@grape.net
-----------------------------------------------------------------------------
Internet: ed.h...@grape.net (Ed Haynes)
- The Electronic Grapevine, Napa, CA (707) 257-2338
-----------------------------------------------------------------------------
Alex Duncan
In article <3tppnj$d...@newsbf02.news.aol.com> Pat Dooley,
patd...@aol.com writes:
>(iii) The relative position of the larynx
The human larynx position probably evolved within the last 100,000 years.
Your theory suggests that hominids were in their aquatic phase between 7
and 4 Myr ago. Please reconcile this for us.
>(iv) Subcutaneous fat layer (Have you ever done a comparative
>dissection of the various species under discussion)
Yes, I have done dissection of many of the species under discussion,
including chimps, gorillas and baboons. And yes, they all have
subcutaneous fat.
I've pointed out previously that human fat distribution is not
what we would expect to see in an aquatic animal. Have you no response?
(Well, there isn't one, is there?)
>(vi) Cooling mechanisms
The human cooling mechanism has been explained perfectly adequately as a
very efficient adaptation to diurnal terrestrialism. Why would such a
cooling mechanism have evolved in the water?
>(vii) Loss of oestrus in human females
Your really out of touch here. There are those who suggest that oestrus
is "concealed" in human females. A more interesting suggestion is that
human females have "permanent" oestrus. And no, I don't mean they're
continuously ovulating. However, human males are sexually interested in
females at ALL times during the cycle. This has been adequately and
reasonably explained as an adaptation to different male and female
reproductive strategies.
By the way, very few mammals other than humans produce so much
blood during menstruation. This could be another fact you could
integrate into the AAT. Oh, wait, it wouldn't work -- blood attracts
sharks.
>(viii) Different structures for supplying blood to the brain
Where'd you get this one and what does it have to do with AAT? Are you
suggesting that other primates supply blood to the brain from some source
other than the carotid and vertebral arteries?
Clara N. Fitzgerald
>Re: Bipedalism and other factors
>>From: her...@gmu.edu (Harry Erwin)
>
>>> There is also the issue of residual webbing in humans. That useless
>>> flap of skin between your thumb and forefinger is the only thing
>>> that restricts the movement of your thumb back another thirty degrees;
>>> other apes don't have such a flap. A significant percentage of humans
>>> still have further vestigal webbing between their fingers and toes.
>>
>>The thumb/first-finger web is the primary path by which large external
>>forces are coupled to the hand structure in man.In the apes,the thumb is
>>reduced or(in the gibbons)adapted to swing out of the way and the forces
>>are transmitted via the fingers, which are vulnerable to breakage and
>>other injury and so must be fairly tough and indelicate. Yes, the web
>>restricts thumb mobility, but it allows the thumb and fingers to be
>>delicate manipulatory appendages with a reduced risk of damage.
(I seem to remember a genetically transmitted variation in angle
of thumb movement; some portion (I can't recall my 8th grade biology
course figures right now) of the population has 'hitch-hiker's thumb',
probably about a 10 degree difference)
What exactly do each of you mean by the 'web'? There is some underlying
muscle, which allows a precision grip and probably enhances a power grip,
and there is a loose flap of skin which prevents the thumb from bending
very far from the hand. The skin flap is considerably larger than the
muscle boundaries.
>>--
>>Harry Erwin
>Pat Dooley
--
Clara N. Fitzgerald
>patd...@aol.com (Pat Dooley) wrote:
>>Re: Bipedalism and other factors
>>>From: her...@gmu.edu (Harry Erwin)
>>
>>I wrote:
>>Other unique adaptations that facilitate human diving include:
>>1 .Hairlessness ( to reduce drag on descent and ascent)
>I believe there are studies that show that it actually makes no
>difference.
[How often do you go swimming? Just curious] There's an large
sports swimming culture convinced that shaving down lets them go faster.
Hence swim caps, etc. I don't have much body hair, but my head hair
is about a foot long, and braided is less drag than a pony tail, which
is vastly less than loose (Makes butterfly very difficult; neck
snaps back). Should I post these studies on the rec.sport.swimming
group?
>>3. Descended larynx
>The neandertal larynx is only partially descended compared to our own.
Could they breathe air into their lungs through their mouths, and
how easily (compared to us) did they choke?
>More importantly, newborn infants do not have a descended larynx.
What exactly do you mean by "more importantly"? This is evidence
that the choking hazard from a descended larynx is significant?
>>4. Bipedalism (keeps legs, spine and head in one plane)
>There are no aquatic bipeds.
Penguins are mentioned periodically...
Pat Dooley
<< deletions>>
I wrote:
>>The human diving reflex is more than a simple nervous system adaptation.
>>For example, in simulated deep dives under laboratory conditions it was
>>found that the circulation to the limbs was completely shut down and
>>the heart rate slowed to about 12 beats per minute.
Phil Nicholls (pn...@globalone.net) replied:
>As has been posted several times before, the "human" diving reflex is
>also present in dogs and any other mammal that you can train to dive
>and thus remove the fear such an activity would otherwise entail.
>Check "Aquatic Ape: Fact or Fiction."
No one is denying the existence of the diving reflex in
other mammals. The question to be answered is whether or
not the reflex in humans is out of the range one would
expect for arboreal apes.
If the performance of your diving dogs matched the performance
of humans, I would be impressed. I presume it isn't in the
same league since you have failed to provide any information
on the extent of heart beat reduction, the degree to which
the blood supply is cut off to the limbs, the depth of their
dives, and the duration.
>
>>Other unique adaptations that facilitate human diving include:
>
>>1 .Hairlessness ( to reduce drag on descent and ascent)
>
>I believe there are studies that show that it actually makes no
>difference.
Olympic swimmers either cover their heads with a bathing
cap or cut off their head hair to reduce drag. Male swimmers
even find further advantage in shaving off their residual
body hair. In the latter case, I saw claims that shaving
off leg and chest hair cut times by 0.5 to 1 sec over 100m.
If they were as shaggy as the average chimpanzee I have
no doubt they would have registered an even greater
improvement by shaving.
>
>>2. Downward pointing nostrils (that stops water from being forced into
the
>>nasal cavities)
>
>The direction of human nostrils is a result of (a) being catarrhine
>primates and (b) lose of facial prognathism. Early hominids did not
>have noses like ours.
>
(a) Then why don't chimps and gorillas have something
similar?
(b) Who knows? Flesh and cartilage don't fossilize. The
nose is a bit short of musculature so one can't tell
the structure from muscle attachment points. Who knows
anything of the shape and dimensions of other fleshy
appendages in our early ancestors?
>>3. Descended larynx
>
>The neandertal larynx is only partially descended compared to our own.
>More importantly, newborn infants do not have a descended larynx.
>
Newborn infants have a priority need to be able to suckle
and breath at the same time. The non-descended larynx they
share with most other mammals lets them do both.
If the Neanderthal larynx is only partially descended, (and
this would be difficult to determine from bones alone)
that may indicate that further descent of the larynx was
required to facilitate fully developed speech.
>>4. Bipedalism (keeps legs, spine and head in one plane)
>
>There are no aquatic bipeds.
Penguins are aquatic bipeds. As you have frequently pointed
out, primates are partially adapted to bipedalism. Few other
mammal groups have such a predisposition and none of those
that made the transition from land to sea had it. If a
stranded population of apes made a partial transition to
an aquatic existence (the central thesis of the AAT), then
it would be the first example of a mammal so predisposed
to do so. The fact remains that all aquatic mammals maintain
their limbs, spines and skulls in a plane. Only one ape
does the same.
Pat Dooley
Pat Dooley
In response to Phil Nicholls long post on the subject,
I can only quote my original source.
The source is : The skin of non-human primates by William
Montagna in Am. Zoologist, 12:109-124 (1972)
(A systematic study) "failed to explain the unique feature
of human skin - its almost complete nakedness."
re eccrine glands in primates :"One might surmise that, like
man, these animals sweat in response to heat stimulation.
However, with singular exceptions, if the glands secrete at
all, the amount is so small that it cannot be recorded.
Sometimes animals show beads of sweat on the facial
disc when under deep anesthesia, but our efforts to induce
thermal sweating have failed. We have also largely failed to
induce sweating with sudorific drugs. In the chimpanzee,
very few, small sweat drops were recorded even after the
administration of shockingly large doses of these drugs."
"why do these glands not function when they seem to have all
the equipment for doing so?"
"It appears, then, that eccrine glands are relatively new
acquisitions in the hairy skin of primates and that only in
man do they really serve the purpose of thermoregulation."
So, unless Phillip Nicholls can give us information on more
recent experiments where researchers could induce eccrine
sweating in chimpanzees through thermal stress, I'll stand
by the AAT position that man is unique amongst the apes in
using profuse eccrine sweating for thermo-regulation.
Pat Dooley
HARRY R. ERWIN
: Subject: Re: Bipedalism and other factors
: << deletions>>
: >
: >>2. Downward pointing nostrils (that stops water from being forced into
: the
: >>nasal cavities)
: >
: >The direction of human nostrils is a result of (a) being catarrhine
: >primates and (b) lose of facial prognathism. Early hominids did not
: >have noses like ours.
: >
: (a) Then why don't chimps and gorillas have something
: similar?
The point made here is not quite clear. Chimps and gorillas (and orangs)
lack noses. Ditto for Proconsul. Primitive hominids also appear to have
lacked noses. Hence a nose is a new trait. Why did it evolve? Perhaps it
was a neutral trait that hitch-hiked on something else, but on the other
hand, there does seem to be a climatic gradient, and neanderthals seem to
have gone even further here than H. sapiens, so it may have been adaptive
to cold weather conditions to have an extended nose.
: (b) Who knows? Flesh and cartilage don't fossilize. The
: nose is a bit short of musculature so one can't tell
: the structure from muscle attachment points. Who knows
: anything of the shape and dimensions of other fleshy
: appendages in our early ancestors?
Quite a bit for the most part, although data on the evolution of the penis
is limited, other than an enormous os baculum from Messel on an Eocene
lemur. (How do we know 'lemur'? Toilet claws. Of course, Messel is such a
strange site--e.g., Europotamandua--that one can ->speculate<- that it was
a zoo. 8)
: Penguins are aquatic bipeds.
So is any waterbird. The bipedalism seems to have preceded the adaptation
to water.
: As you have frequently pointed
: out, primates are partially adapted to bipedalism. Few other
: mammal groups have such a predisposition and none of those
: that made the transition from land to sea had it. If a
: stranded population of apes made a partial transition to
: an aquatic existence (the central thesis of the AAT), then
: it would be the first example of a mammal so predisposed
: to do so. The fact remains that all aquatic mammals maintain
: their limbs, spines and skulls in a plane. Only one ape
: does the same.
All aquatic mammals? Otters, beavers, polar bears, Paleoparadoxa,
hippos,... all seem to be quadrupeds.
: Pat Dooley
Elaine Morgan
>name one aquatic mammal that became bipedal"
Nobody can name any nonhuman animal aquatic or otherwise that became
bipedal so that's a bit pointless-
> name one aquatic mammal that weeps for grief and I will eat your
computer.
I can't let you do that: I have enough trouble with in its unmasticated
state.
But Steller, the one that Steller's seacow was named after. reported
that when he separated a sea otter from its cubs, so that it could see
them but not reach them, it wept. You may say that is anecdotal but you
can't deny it is an experiment that could very easily be repeatd
Reply to Nicholls.
You say our nostrils point down (a) because we are catarrhine. Every
higher primate east of the Atlantic is catarrhine. Why don't all their
nostrils point down?
(b) because of loss of facial prognathism. This is an old story, which
says it wasn't the nose that stuck out, it was the rest of the face
that shrank back. --as if that explained anything. So why didn't the
nose shrink back when everything else was doing it?
(c) early hominids did't have nostrils like ours. Nobody knows what
they were like. You only know they didn't have an ossified nasal spine.
Neither does a sea elephant, but it's got quite a remarkable appendage
all the same.
Reply to Alex Duncan.
You say there is plenty of evidence in the current literature of
savannah-mosaic adaptation but I have ignored it
Quite untrue. What there is in the current literature is a great deal
of speculation about why a savanna/mosaic habitat might have led
to bipedalism. I have not ignored it. I have a paper in press listing
the front-running theories and saying why I disagree with them. They
also of course disagree with one another.
You mention credibility. Suppose you establish your credibility by
telling us which of these mutually contradictory theories you believe;
then I can defend mine by giving my opinion of it. This request is
usually met with with "Oh but there are so many of them.." You are
doing this again. It is a blatant cop-out. Stand up and be counted.
Then we have a meaningful discussion.
Reply to Holloway.
I will name no more names of people who think I am not a crackpot. I
won't even betray the one who figured on your proffered list of the
great and good. In your book they instantly become non-persons, and I
know that even when the non-persons have become the majority, you will
still be faithfully flying the flag for the flat-earthers.
You keep reiterating that there are many brilliant and illustrious
people (I don't deny the brilliance) who despise AAT. You seem amazed
that that doesn't make me roll over and play dead. Well, if they opened
their lips and gave their reasons I might be swayed by their arguments.
But the tactic of silent contempt, while it may impress their
students, leaves me cold. Brilliant people have backed the wrong horse
more than once in scientific history.
Thank you for confirming my hunch that you haven't read my last two
books. It must make it a lot easier to condemn a theory out of hand
when you don't confuse the issue by finding out what it actually says.
You said "Nothing's been disproved, Elaine." Does this mean that the
savannah theory in all its pristine glory, has not been abandoned after
all? That is odd, because recently on this thread someone who referred
to the torrid-heat scenario was rebuked for contructing a straw man to
attack, on the grounds that nobody believes in that any longer. Could
you perhaps tell us what kind of habitat you personally believe
Afarensis lived in? That would be really helpful in clarifying the
matter.
Cheers,
Elaine
David L Burkhead
>Reply to Burkhead:
>
>>name one aquatic mammal that became bipedal"
>
>Nobody can name any nonhuman animal aquatic or otherwise that became
>bipedal so that's a bit pointless-
1) The claim is often made that an aquatic stage was important
stage in the development of bipedalism in humans.
2) The objection often raised to savannah theories is that "no
other savannah creature has developed this approach."
3) "No other aquatic creature has developed this approach."
If the argument works for your, it works against you just as well.
>
>> name one aquatic mammal that weeps for grief and I will eat your
>computer.
>
>I can't let you do that: I have enough trouble with in its unmasticated
>state.
>
>But Steller, the one that Steller's seacow was named after. reported
>that when he separated a sea otter from its cubs, so that it could see
>them but not reach them, it wept. You may say that is anecdotal but you
>can't deny it is an experiment that could very easily be repeatd
>
Note that I _also_ said use the same standard you would accept as
evidence for primate weeping for grief. I have seen a chimpanzee
female, whose young offspring has died, weep from grief. If _your_
anecdote is acceptable, then _my_ anecdote is acceptable.
>Reply to Nicholls.
>
>You say our nostrils point down (a) because we are catarrhine. Every
>higher primate east of the Atlantic is catarrhine. Why don't all their
>nostrils point down?
A chimpanzee has a protruding snout. Put a chimpanzee nose on a
human face and, lo and behold its nostril points down.
>(b) because of loss of facial prognathism. This is an old story, which
>says it wasn't the nose that stuck out, it was the rest of the face
>that shrank back. --as if that explained anything. So why didn't the
>nose shrink back when everything else was doing it?
Why should it? Contrary to the myths common to the "popular"
versions of evolution, not everything has a reason.
>(c) early hominids did't have nostrils like ours. Nobody knows what
>they were like. You only know they didn't have an ossified nasal spine.
>Neither does a sea elephant, but it's got quite a remarkable appendage
>all the same.
You contradict yourself here. If nobody knows what early hominid
nostrils were like, then it is not justified to say what they were, or
were not, like. If nobody knows what they were like, then you cannot
make a pronouncement like "early hominids didn't have nostrils like
ours." You may _assume_ it, but that's all it is--an assumption.
So far, that's all I see--assumption, smoke and mirrors.
Ralph L Holloway
> Reply to Holloway.
>
> I will name no more names of people who think I am not a crackpot. I
> won't even betray the one who figured on your proffered list of the
> great and good. In your book they instantly become non-persons, and I
> know that even when the non-persons have become the majority, you will
> still be faithfully flying the flag for the flat-earthers
(This is surely the kettle calling the pot black)
This kind of snotty and simply untrue reply does you no great credit,
Elaine. It shows you to be simply incapable of reason, and having a
propensity to get dirty and go to the mat when it is unnecessary.. If I
demur from
granting Dawkins, EO Wilson, Calvin, and now Robin Dunbar expertise as
researchers into the evolution of human bipedalism, where does that
indicate that I regard them as "non-persons"? Please keep it in mind that
the phrase "non-persons" is yours, not mine. Shows where your mind is,
and it confirms for me that perhaps I should entertain the hypothesis
that it is really you who is the "non-person"... You really want to go down
this personal vindictive road?
> You keep reiterating that there are many brilliant and illustrious
> people (I don't deny the brilliance) who despise AAT. You seem amazed
> that that doesn't make me roll over and play dead. Well, if they opened
> their lips and gave their reasons I might be swayed by their arguments.
> But the tactic of silent contempt, while it may impress their
> students, leaves me cold. Brilliant people have backed the wrong horse
> more than once in scientific history.
This is just ad hominem crap, and I'm frankly surprised you would let it
off your keyboard. I have never said anything about "many brilliant and
illustrious people, blah, blah." As I recall, I said there are several
paleoanthropologists who have spent their lives studying primate
locomotion and hominid bipedalism in particular, I mentioned but a few,
and suggested I had never heard their support for your HYPOTHESIS, (I'm
tired of seeing it elevated to the status of "theory".) If I said they
"despise AAT", I stand corrected, because I've haven't heard anything
positive yet about AAH from the experts, nor have I heard them talking
very seriously about your hypotheses. I'll be truly amazed to discover
long in the future that they backed the wrong horse. .. You ever have
trouble getting your head through the door?
> Thank you for confirming my hunch that you haven't read my last two
> books. It must make it a lot easier to condemn a theory out of hand
> when you don't confuse the issue by finding out what it actually says.
My participation in this thread was to come in after reading so much bad
primatology from your two adherants, Troy and Dooley. But you are
absolutely confirmed in your conclusion, Elaine, I have not read your
books in full, and I am not altogether sure that I should, would, or
will. I have no real investment in theories of bipedalism except to have
a fair sense of what constitutes evidence. All your name dropping
business of the last few posts rubbed me the wrong way re: evidence for
AAH.
>
> You said "Nothing's been disproved, Elaine." Does this mean that the
> savannah theory in all its pristine glory, has not been abandoned after
> all? That is odd, because recently on this thread someone who referred
> to the torrid-heat scenario was rebuked for contructing a straw man to
> attack, on the grounds that nobody believes in that any longer. Could
> you perhaps tell us what kind of habitat you personally believe
> Afarensis lived in? That would be really helpful in clarifying the
> matter.
I think A. afarensis lived in a mixture of environments: savannah, Gallery
forest adjacent to streams. I would not expect that their bipedal
adaptation meant that they spent all their time out in the savannah. I
have no problem imagining that they retained some aspects of arboreal
adaptations, such as climbing with greater facility than say, early Homo.
I accept their footprints at Laetoli as being made by A. afarensis, and
that they were truly bipedal. I know of nothing that I have studied in
the last 36 years of my student and professional teaching life that leads
me to accept any of the items you and your followers mention as true
evidence for an aquatic phase in either hominid or hominoid evolution.
I sincerely doubt, however, that my personal beliefs could really be
helpful in "clarifying the matter". I stand by what I said earlier. All
the new finds and analyses of possible arboreal rententions do not mean
that the standard model of bipedal evolution have been disproved. The
newer finds, in particular Ardipithecus, haven't even been described yet.
I mentioned it before and I will say it again. I think, from all I
have read and studied, that the AAH thing is very farfetched, and that I
find it easier to believe that some of the UFO sightings can be proved
more easily than AAH. After all, each of ten billion galaxies has about
ten billion stars, and that's just in this Universe, not counting all the
possible other universes. That one planet in one of these 10 to the 20th
power might be bright enough to solve gravity problems but be stupid
enough to visit Earth seems to me more probable than the scenarios I have
seen here.
Cheers,
Ralph Holloway.
Gerold Firl
>sweating in chimpanzees through thermal stress, I'll stand
>by the AAT position that man is unique amongst the apes in
>using profuse eccrine sweating for thermo-regulation.
It is clear that we have a uniquely developed thrmo-regulation system;
however, this is a clear adaptation for high-temperature terrestrial
activity. In no way does this support the AAT.
--
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Disclaimer claims dat de claims claimed in dis are de claims of meself,
me, and me alone, so sue us god. I won't tell Bill & Dave if you won't.
=-=-=-=-=-=-=-=-=-=-=-=-=-=---- Gerold Firl @ ..hplabs!hp-sdd!geroldf
William Baird
MUHAHAHAHAHHAHA!!!!! Something I *CAN* comment about with authority!
> [How often do you go swimming? Just curious] There's an large
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
*bows* Former Los Alamos High School swim team member: nickname: Goose. ;)
>sports swimming culture convinced that shaving down lets them go faster.
There's that reason that you mention, but there's another too.
When you swim fast, you build up an acid in your muscles (we had a
lecture by a swim coach on teh matter. . .) (lactic I think) and it
causes a burning session. Appaarently, by shaving, you, somehow, reduce
the build up rate. However, it doesn't stop it. After a while you
generally HAVE to stop swimming (remmeber the burning sensations in your
muscles after practice? That's teh acid). I could, I suppose, use this
as an arguement against teh aquatic ape hypothesis if I knew what the
similar situations were for other aquatic animals...but I don't. I just
remember this from a swim team lecture by Steve Myers (???? I think).
It made sense, but I'm not an atanomy type. I like to watch stars, not
dissect things. Can someone confirm/deny this?
>Hence swim caps, etc. I don't have much body hair, but my head hair
>is about a foot long, and braided is less drag than a pony tail, which
>is vastly less than loose (Makes butterfly very difficult; neck
>snaps back).
*remembers The Fly*whimpers* 50 & 100 Free. 100 Breast were my events.
>Should I post these studies on the rec.sport.swimming
>group?
Nah. It'll prolly die after this post....
Will
Will Baird InterNet: wba...@nmsu.edu chpw...@arriba.nm.org
Astronomy/Physics Undergrad President
New Mexico State University TimeSlice Computing and Networking Corp.
'Money talks. Usually it says, "Bend over"'- Solomon Short, AMFM; D Gerrold
Ralph L Holloway
This is the beginning of what may be a long set of communications.
This particular one is not very intense and not very long, nor in very
much depth. I've corrected my outlook on your AAH, and have decided to
take you very seriously indeed. Consequently, I have read most of your
two books, "Scars of Evolution" and "The Aquatic Ape". I should finish
them in a day or so.
I'd like to make some observations. First, I like the way you write.
It is clear, has humor, and is entirely engaging. I does have facts and
interpretations, and you have been making very serious efforts at synthesis.
Secondly, I still believe that there are serious contradictions in your
understanding of evolutionary theory and how you apply it to the problems
of the fossil record, behavior of living animals and the
paleontolotgical past. I will try to enlarge on that criticism somewhat
later.
Third, as I explained in a previous post, I came to AAH through Sci.
anthropology. paleo, and thus many of my reactions were to the exchanges
I encountered between Mr. Dooley, Mr. Troy, Phil Nichols, J. Moore, Alex
Duncan, etc., etc. Myt only point here is that I believe Mr. Dooley and
Mr. Troy have pretty accurately characterized most of the major points
of your hypothesis, and that the "detractors" have also fairly
characterized your position and offered illuminative critiques of some of
sequelae of your hypothesis (e.g., tears, fat, predation, fossil record,
heat dissipation, etc.), some of which have involved useful research
(without playing favorites I might mention the innervation of the
lacrimal glands, composition of tear, and yes, the crocodile information,
which I certainly never found "tedious"). I was very worried that in fact by
paying so much attention to these
fragments I might have been quite in error in not going directly to the
source ( and I thank you for providing Hardy's comments in the Appendices
of the AA book). I find that I am not that much in error, but do regret
that I hadn't done the proper thing which is always to consult the
original and not second hand attempts. I don't blamed you for being
pissed off at me, and publicly apologise.
Let me start with page 1 of "Scars...". You mention that the sheer
resemblance between ourselves and the African apes suggested to Darwin
that we share a common ancestry. You then say that "...this solution
immediately raised a further problem. If we are so closely related to
them-and everything we have learned since suggests that the relationship
is even closer than Darwin-supposed-then why are we not more like them?"
You might as well ask why we are not identical to each other. The
differences strike some as enormous and others as minimal. The molecular
genetic evidence suggests about 1% between ourselves and chimpanzee, and
only slightly more between ourselves and gorilla. Ah, but that one %? It
seems most likely that regulatory (rather than structural ones) genes will
eventually be identified to
explain differences in growth rates, durations, initiations and
cessations of various cell lines, etc, that will account for almost all
of the minor morphological differences we see. The game is still on to
really demonstrate true physiological differences between ourselves and
the great apes. Chimpanzees have been observed to weep over lost
relatives, and Gorillas have been observed to sweat.
You go on to say "... When a species splits and gives rise to three
separate lineages, there is no reason to expect that species C will
differ from A and B any more widely than A and B differ from one another.
Yet in the case of the anthropoids this is what happened..."
GG Simpson, the paleontologist has some excellent discussions of
morphological differences in one of Washburn's edition volumes that the
Wenner -Gren published (I think it is the one on Classification). It is
worth reading, because I know of none
trained in paleontology who would make the claim you have. Speciation is
something that happens between populations because they are usually
confronted by different environments and are most often faced with some
barrier, usually geographic, to gene flow. It is perfectly reasonable to
expect that the total conditions faced by C might be quite different that
those faced by A and B. Remember, evolution is opportunistic, and without
a fossil record for chmpanzee and gorilla, we cannot hope to know whether
the deparation as between Aand B to C was a truly punctuated event,
whereas between A and B, the punctuation was less manifest. At least
consider random genetic drift as a partial evolutionary force in this
A,B, C scenario, and there might be very good reasons why the differences
between A,B,C are not uniform.
In essence, although you don't mean it so, you statement on page 3
that: "...the essential point is that evolution takes place in response to
things which have happened (italics yours), not things which are
predestined to happen. Man is no more an evolutionary pinnacle than a
tree is, or a termite or an octupus. His emergence was no more inevitable
than that of any other species." This is surely correct, but it flies in
the face of what you previously said, and what follows below:
"The present state of play may be summarised as follows. Four of the
most outstanding mysteries about humans are: (1) why they walk on two
legs? (2) why have they lost their fur? (3) why have they developed such
large brains? (4) why did they learn to speak?
The Orthodox answers to these questions..." you say, is "we do not
yet know..."
The problem for me is that you so overstress the differences as to
almost make them of a quantum nature. I don't see chimpas and gorillas as
furry. I see them having more hair than we do. Humans haven't lost their
"fur" (please, hair), there is less of it, which incidentally varies
widely among different human groups, and in which case, to be true to
your logic, would involves various dregrees of an aquatic adaptation in
different human groups...I don't see the
differences between ape locomotion and our own as something more than
modifications of existing anatomy and neurological and
neuromuscular integration that makes bipedalism
a quantum leap from knuckle-walking, or as something so incredibly
different that it required evolutionary nourishment in an aquatic medium
for a couple of million of years. More to the point, it is arguable if we
can ever "know" in the sense you might have meant "we do not know yet",
but some of the alternative hypotheses out there do actually suggest
reasons 'why', such as the standard savannah standard theory, or some of
Wheeler's ideas regarding heat loss, sweating, hair, etc.
In sum, I am not convinced that you always apply the same standards
to your ideas regarding evolutionary dynamics that you apply to others.
This is very striking to me when I read ytour statement regarding the
savannah theory on page 8: "One serious weakness in the savannah theory
lies in the disproportion between the commonplace event it depicts and
the spectacular consequences alleged to have flowed from it. Many primate
species such as baboons and vervet monkeys and patas monkeys have left
the trees to live on the savannah. They have lived there quite as long as
your ancestors ever did, YET THEY SHOW NO SIGNS OF ACQUIRING ANY
HUMAN-LIKE FEATURES SUCH AS HAIRLESSNESS OR BIPEDALISM (emphasis mine)".
This expectation flies in the face of all of your previous 7-8 pages of
references to evolutionary theory. You expect species in different
superfamilies to give the same adaptive response to the same environment?
I thought you said evolution works on the genetic materials at hand...Why
these monkeys, who incidentally are never far from trees, or in the case
od baboons, acacia thorn trees, should develop the same adaptations as
the human animal based on what I know of evolutionary theory and genetics
is totally beyond my understanding. It is like expecting all sea animals
to be morphological the same. They aren't.
So there is my initial reaction to your first hand first chapter in
"Scars..." I still believe that the anatomical and physiological details
that create "problems" for standard scenarios are far overblown and that you
are selectively using evolutionary paradigms to suit your purposes.
If I have duplicated some previous discussions of earlier AAH
threads that I have't seen, forgive me. More will come.
Ralph Holloway.
Alex Duncan
Ela...@desco.demon.co.uk writes:
>Jim Moore wrote at one point " I have seen Pond produce articles
>showing that human fat distribution and properties do not meet the
>requirements of the AAT, which Morgan has ignored."
You really don't need citations to know human fat distribution doesn't
meet the requirements of the AAT. Fat is distributed differently both
between the sexes, and between different populations. Most importantly
though, is the fact that fat is distributed unevenly over the body. In
males, of course, most fat is deposited in the region of the belly, while
in females most fat is distributed in the breasts, hips, buttocks and
upper thighs (is it a coincidence that these are areas of visual
stimulation for most males? -- I think not).
In most ocean going mammals fat is evenly and thickly distributed over
most of the body, as it has to be to prevent heat loss. In humans, there
is generally NO fat or very little fat over the areas that are most
susceptable to heat loss. These would be the head, and the distal
extremities (arms from the elbows down and legs from the knees down).
Anyone familiar with basic scaling knows that a long slender cylinder
(shin & forearm) has much more surface area relative to volume than a
short, fat cylinder (thigh & upper arm), and is thus subject to rapid
heat exchange with the outside environment. This being so, the "shins"
and forearms of aquatic humans would be regions of rapid heat loss, and
we might expect them to have thick layers of fat to prevent this.
Instead we see virtually no fat, and indeed, on the forearm at least,
many major veins exist immediatly beneath the thin ventral skin, where
they can dump heat extremely rapidly.
The head and neck would be even more of a problem. Up to 1/3 of
the body's blood supply goes to the head, and again, much of it returns
to the torso in veins immediately beneath the nearly fatless skin
(external jugular & the internal jugular in the space immediately behind
the gonial angle of the mandible, facial, communicating branch between
facial and anterior jugular, occipital, retromandibular).
Phil Nicholls
>Reply to Burkhead:
>>name one aquatic mammal that became bipedal"
>Nobody can name any nonhuman animal aquatic or otherwise that became
>bipedal so that's a bit pointless-
Elaine, the who thrust of your argument is convergent evolution. It
is a valid question to ask where the convergence is when it comes to
bipedalism. The short answer is that there is none. Since no one
else is trying to make a case for convergence we don't have that
burden.
>> name one aquatic mammal that weeps for grief and I will eat your
>computer.
>I can't let you do that: I have enough trouble with in its unmasticated
>state.
>But Steller, the one that Steller's seacow was named after. reported
>that when he separated a sea otter from its cubs, so that it could see
>them but not reach them, it wept. You may say that is anecdotal but you
>can't deny it is an experiment that could very easily be repeatd
Don't you think the account might be a case of anthropomorphizing?
How do you know the animals state of mind? Do you have any evidence
that the lacrimal glands of a sea cow are innervated by limbic
structures?
>Reply to Nicholls.
>You say our nostrils point down (a) because we are catarrhine. Every
>higher primate east of the Atlantic is catarrhine. Why don't all their
>nostrils point down?
They do.
>(b) because of loss of facial prognathism. This is an old story, which
>says it wasn't the nose that stuck out, it was the rest of the face
>that shrank back. --as if that explained anything.
It does.
> So why didn't the nose shrink back when everything else was doing it?
The face "shranks" in response to the reduction in size of the
anterior dentition. There is no reason why the nasal open or nasal
bones would be affected by this. It's called mosaic evolution.
>(c) early hominids did't have nostrils like ours. Nobody knows what
>they were like. You only know they didn't have an ossified nasal spine.
To the extent that we can reconstruct the anatomy of any hominid, the
nose is relatively easy. Australopithecines lack the projecting nasal
bones of modern Homo sapiens. They have rather good sized snouts and
slight concaved facial profiles, very much like that seen in the
chimpanzee.
>Neither does a sea elephant, but it's got quite a remarkable appendage
>all the same.
Yes, well that's very nice. It still doesn't change the fact that
australopithecines did not have noses like modern humans.
Phil Nicholls (pn...@globalone.net)
"To ask a question you must first know most of the answer."
- Robert Sheckley
Alex Duncan
Ela...@desco.demon.co.uk writes:
>Reply to Alex Duncan.
>
>You say there is plenty of evidence in the current literature of
>savannah-mosaic adaptation but I have ignored it
>
>Quite untrue. What there is in the current literature is a great deal
> of speculation about why a savanna/mosaic habitat might have led
>to bipedalism. I have not ignored it. I have a paper in press listing
>the front-running theories and saying why I disagree with them. They
>also of course disagree with one another.
When I talk about evidence, I am not refering to people's hypotheses
about the importance of the savanna/mosaic environment in human
evolution. I am refering to evidence that we can place in two different
categories: 1) reconstruction of the environments in which early hominids
lived, and 2) reconstruction of the locomotor habits of early hominids.
In category 1 are a series of papers that reconstruct environments at
Laetoli and Hadar as savanna/mosaic (with emphasis on mosaic) (later
habitats like Sterkfontein were probably drier), and in category 2 are
papers that reconstruct the locomotor behavior of early hominids as being
primarily terrestrial bipeds, with retained capacities for tree climbing.
Here is a list of such references:
Paleoenvironment:
-- Andrews PJ (1989) Paleoecology of Laetoli. J. Hum. Evol., 18: 173 -
181.
-- Boaz NT & Burkle LH (1984) Paleoclimatic framework for African hominid
evolution. In (JC Vogel, ed.) Late Cainozoic Palaeoclimates of the
Southern Hemisphere, pp. 483-490. Rotterdam: Balkema.
-- Bonnefille R, Vincens A & Buchet G (1987) Palynology, stratigraphy and
palaeoenvironment of a Pliocene hominid site (2.9 - 3.3 M.Y.) at Hadar,
Ethiopia. Palaeogeography, Palaeoclimatology, Palaeoecology, 60: 249 -
281.
-- Bonnefille R & Riollet G (1987) Palynological spectra from the Upper
Laetolil Beds. In (MD Leakey & JM Harris, eds.) Laetoli: A Pliocene Site
in Northern Tanzania, pp. 52-61. Oxford: Clarendon Press.
-- Gentry AW (1987) Pliocene Bovidae from Laetoli. In (MD Leakey & JM
Harris, eds.) Laetoli: A Pliocene Site in Northern Tanzania, pp. 378-408.
Oxford: Clarendon Press.
-- Grey BT (date & title unknown) Grey's PhD dissertation reconstructs
paleoenvironment at Hadar as being similar to modern Omo River region.
-- Harris JM (1985) Age and paleoecology of the Upper Laetolil Beds,
Laetoli, Tanzania. In (E Delson, ed.) Ancestors: The Hard Evidence, pp.
76 - 81. New York: Alan R. Liss, Inc.
-- Johanson DC, Taieb M & Coppens Y (1982) Pliocene hominids from the
Hadar Formation, Ethiopia (1973-1977): Stratigraphic, chronologic and
paleoenvironmental contexts, with notes on hominid morphology and
systematics. Am. J. Phys. Anthrop., 57:373-402.
These are, of course, just a few of many references which reconstruct
paleoenvironments at early hominid localities. For the most part they
all tell the same story: savanna/mosaic.
Early hominid positional behavior:
-- Day MH & Wickens EH (1980) Laetoli Pliocene hominid footprints and
bipedalism. Nature, 286: 385-387.
-- Duncan AS, Kappelman J & Shapiro LJ (1994) Metatarsophalangeal joint
function and positional behavior in Australopithecus afarensis. Am. J.
Phys. Anthrop., 67-81.
-- Gomberg DN (1985) Functional differences of three ligaments of the
transverse tarsal joint in hominoids. J. Hum. Evol., 14: 553-562.
-- Jungers WL (1982) Lucy's limbs: skeletal allometry and locomotion in
Australopithecus afarensis. Nature, 297: 676-678.
-- (1988) Relative joint size and hominoid locomotor adaptations with
implications for the evolution of hominid bipedalism. J. Hum. Evol., 17:
247-265.
-- Lamy P (1986) The settlement of the longitudinal plantar arch of some
African Plio-Pleistocene hominids: a morphological study. J. Hum. Evol.,
15: 31-46.
-- McHenry HM (1986) The first bipeds: a comparison of the A. afarensis
and A. africanus postcranium and implications for the evolution of
bipedalism. J. Hum. Evol., 15: 177-191.
-- Stern JT & Susman RL (1983) The locomotor anatomy of Australopithecus
afarensis. Am. J. Phys. Anthrop., 60:279-317.
-- Susman RL, Stern JT & Jungers WL (1984) Arboreality and terrestriality
in the Hadar hominids. Folia Primat., 43: 113-156.
In combination, these articles do two things. They establish that early
hominids were living in a savanna/mosaic environment, and they
demonstrate that they had the proper locomotor anatomy to take advantage
of such an environment. What more could you ask for? (BTW -- I've only
just dented my list of references. You might try actually reading some
of this.)
>You mention credibility. Suppose you establish your credibility by
>telling us which of these mutually contradictory theories you believe;
>then I can defend mine by giving my opinion of it. This request is
>usually met with with "Oh but there are so many of them.." You are
>doing this again. It is a blatant cop-out. Stand up and be counted.
>Then we have a meaningful discussion.
Its not clear to me what you're asking for here. The question of WHY
hominids got up on their hindlimbs and began walking bipedally is one
that we'll probably never be able to answer to everyone's satisfaction.
What we can do is point out some of the potential advantages to the
behavior, and some of the adaptations to the behavior that we see in
living and extinct hominids. Many of the features (sweating,
hairlessness) that you try to steal away as support for the AAT have been
demonstrated to be advantageous to diurnal bipedal hominoids living in
largely open environments.
I don't favor any particular model of WHY hominids are bipedal. I
honestly don't think we'll ever be able to answer the question (although
we can suggest answers -- keep in mind, in science we never PROVE
anything, we can only test our models). As you can tell from some of my
earlier posts, I lean toward a gibbon-like ancestor for hominids, but I
don't have any particular stake in the matter, and wouldn't be too
surprised to see something else turn up.
By the way, you have a perfect opportunity to establish the AAT as a
serious model for the origin of hominid bipedalism. Supposedly, there is
a nearly intact postcranial skeleton of A. ramidus that will be described
soon. If A. ramidus is really about 4 Myr old, then it lived right at
the end of the time period when your proponents say we had aquatic
ancestors. As such, we should expect it to show some skeletal
adaptations to living in an aquatic environment. Does your hypothesis
permit you to make predictions about this? Please, predict for us. What
will the postcranial skeleton of A. ramidus look like?
Nicholas Rosen
Ralph L Holloway <rl...@columbia.edu> says:
>
> Dear Elaine,
>
> The problem for me is that you so overstress the differences as to
>almost make them of a quantum nature. I don't see chimpas and gorillas as
>furry. I see them having more hair than we do. Humans haven't lost their
>"fur" (please, hair), there is less of it, which incidentally varies
>widely among different human groups, and in which case, to be true to
>your logic, would involves various dregrees of an aquatic adaptation in
>different human groups...I don't see the
This relates a bit to something I suggested during a previous round
of debate on the AAH. Given that we seem to have some semi-aquatic
characteristics (and I know that not everyone will give even that),
the question is when did we acquire them? How do we test the AAH
against the AHH (aquatic human hypothesis). I referred to a book,
_Self-Made Man_ by Jonathan Kingdon. Kingdon dismisses the AAH in
one sentence, but claims that many of our more recent ancestors
were strandlopers, to use his word, on and near the shores of the
Indian Ocean. He claims to explain the distributions of various
racial groups on this basis; for example, he points to Negritos
in places like Melanesia, and argues that black Africans are in
fact the descendants of immigrants from across the Indian Ocean.
I suggested trying to compare the AAH and AHH by seeing whether
there are any human populations which have substantially less of
so-called aquatic adaptations than the norm. If, for example,
there are tribes of cold-adapted Siberians, who would be expected
to have relatively little strandloper ancestry, who do not have
webbing on their thumbs, that would be an argument for the AHH,
and tend to make the AAH redundant. One might also look for noses
that would be no good at keeping water out. If no groups with
these characteristics exist, then a small blow has been struck for
the AAH, since we have apparently all inherited aquatic characteristics
from a more remote ancestor.
Of course, I am aware that different human populations have
different amounts of body hair, fat, etc. These can be explained
partly by recent environmental adaptations, partly by genetic drift
and random chance.
Nicholas Rosen
Standard disclaimers apply.
Plus a non-standard disclaimer: I am not an anthropologist.
Ralph L Holloway
what the postcranial morphology of the newer Ethiopian fossils (A.
ramidus) will be like, on the basis of their retention of aquatic
adaptations. This is a very important question and challenge. R. Holloway.
Ralph L Holloway
> Thus, my conclusion is, the more modern the structure
> of the Ramidus skeleton, the less the aquatic hypothesis
> is discounted.
Should we take this to mean that only limb lengths are going to tell us
whether the structures are for aqautic or bipedal or arboreal locomotor
adaptations? "More modern" does mean closer to human, doesn't it? I'm
afraid I didn't understand your post, and I sure don't understand this
conclusion. Can you try again? Ralph Holloway.