The Aquatic Ape's "Mad Minute"
Bob Keeter
Where, & Why. Lets play a little game of journalistic reporting with the
Aquatic Ape Hypothesis.
Who: Some as yet undiscovered ancient ancestor of all modern humans
What: Lived in and around open bodies of water (or swamps) with a lifestyle
sufficiently "aquatic" to favor the evolutionary development of
characteristics and features significantly different from our nearest
cousins (chimps) targeted specifically towards adaptation to the aquatic
environment.
(I'll take the W's out of order, for a reason that will soon become clear.)
Where: Somewhere in equatorial Africa
When: This is a toughie. If hominid obligate bipedalism is supposedly a
product of the aquatic phase, it must have occurred at some point prior to
the first obligate bipedal human ancestors. Even if we throw out
Sahelanthropus for lack of HARD evidence (like the long leg bones and
relatively short arm bones of the Apiths that would render quadrupedalism
extremely difficult if not impossible) that would still push the aquatic
phase quite a ways back in history. The problem there is that all of the
features evolved for the aquatic existence, that were not mutually
advantageous for the bipedal aquatic and bipedal land-dwelling existence,
would be just as actively and aggressively "de-volved" as they had evolved
in the first place! So. . . if you go back too far, we would not have so
much as a trace of any adaptation that was not also advantageous in the
terrestrial environment. (Oh yeah, if whatever supposedly aquatic
adaptation is also evolutionarily advantageous in the terrestrial
environment, there is no need to hypothesize an aquatic phase for its
evolution, which sort of rocks the whole apple cart, doesnt it? 8-) )
Why: On one side I think that this might be a serious question, on the
other, the evidence is that species tend to difuse into just about any
viable ecology, so . . . . . at least the OPPORTUNITIES to difuse into
either a more watery or a much dryer environment than the primal human
ancestors can almost be assumed to be equal possibilities. Possibilities
are good for "working hypotheses", but cant be called real science. so. . .
. . lets just dump the "why" entirely!
So, lets go back to where there is some fat to be chewed, to a question for
the entire AAH community! WHEN would you say that your evolutionarily
significant aquatic phase occurred for ancestoral hominids? How far back to
you put it to allow it to be the genesis of human style bipedalism, without
putting it so far back that any uniquely aquatic impacts on our current
physiology would have simply disappeared? Or is bipedalism simply a non
sequitur with respect to the aquatic ape concept.
Think timeline! 8-) Need a timeline that makes sense when viewed from both
ends and from the middle
And yes, Pauline, this IS a trick question! A question designed to make you
think some very uncomfortable thoughts (other than just that I should quit
typing such herasy of course)! 8-) And Algis, if all of the adaptations of
the aquatic ape concept WERE truely unique adaptations to that watery
environment, why have they not disappeared? AND of course, for both, if
these "aquatic characteristics" were actually mutually advantageous in both
environments, why do we need to hypothesize a "different from the known"
environment to explain their existence?
I know, I know! I was really feeling debative this evening! 8-))
Lets see who is willing to risk a logical rebuttal, reasonable retort, or
constructive response! (Obviously, from the description of the desired
response, excluding the M&M&P troika who simply make noise in that
proverbial empty forest, IMMHO of course!!).
OBTW, (MAD MINUTE: concentrated fire of all weapons for a brief period of
time at maximum rate.)
Regards
bk
Pauline M Ross
wrote:
>So, lets go back to where there is some fat to be chewed, to a question for
>the entire AAH community! WHEN would you say that your evolutionarily
>significant aquatic phase occurred for ancestoral hominids? How far back to
>you put it to allow it to be the genesis of human style bipedalism, without
>putting it so far back that any uniquely aquatic impacts on our current
>physiology would have simply disappeared? Or is bipedalism simply a non
>sequitur with respect to the aquatic ape concept.
Bob, you've asked this question before and I'm sure I've given you an
answer before.
I would say, the 'aquatic phase' lasted from (possibly) the advent of
the ape clade (say 18 Mya), but certainly before bipedalism (say > 6
Mya), through to the start of agriculture (5-10 kya).
--
Pauline Ross
Nick Maclaren
In article <8cfmc.6479$a47....@newsread3.news.atl.earthlink.net>,
"Bob Keeter" <rke...@earthlink.net> writes:
|> In basic journalism you learn that there are "5 w's"; Who, What, When,
|> Where, & Why. Lets play a little game of journalistic reporting with the
|> Aquatic Ape Hypothesis.
|>
|> Who: Some as yet undiscovered ancient ancestor of all modern humans
|>
|> What: Lived in and around open bodies of water (or swamps) with a lifestyle
|> sufficiently "aquatic" to favor the evolutionary development of
|> characteristics and features significantly different from our nearest
|> cousins (chimps) targeted specifically towards adaptation to the aquatic
|> environment.
|>
|>
|> When: This is a toughie. If hominid obligate bipedalism is supposedly a
|>
|> Why: On one side I think that this might be a serious question, ... so. . .
|> . . lets just dump the "why" entirely!
As the saner readers of this group will realise, I do not buy into
any umbrella theory, but feel that there are at least some aspects
of the AAT that make sense. Which does not prove they are right!
Here are a few points:
The when and why (and I am happy to include that) that make most
sense to me are the actual development of fully effective bipedalism,
starting from a chimpanzee-like posture and movement. It is, as far
as I know, the only hypothesis that fits all known facts and does
not require a previous development, with the need to explain why
THAT happened. But there is no good evidence for it, either.
I don't swallow the arguments for subcutaneous fat, hairlessness,
etc. etc., and think that Gould has it right that most are probably
secondary consequences of neoteny, which itself is explained by
the previous development of tool use, communication and childhood
learning.
I have no idea where or when those (mental) skills developed, and
could believe even the savanna, though an aquatic involvement is
equally likely. The fact that most of the savanna arguments are
completely bogus doesn't show that the WHOLE hypothesis is false.
Current belief is that those skills are much later than bipedalism
but, as I understand, there is little good evidence for that.
So I would say that the aquatic phase (assuming it occurred) was
very early, and was the key to separating us from the other African
great apes. I would speculate a small population being trapped in
an area where there was not enough prey to support populations of
the major group-hunting predators, and which was relatively
inaccessible from where they occurred (i.e. the savanna).
There may have been other phases, later, just as there may have been
savanna phases, gallery forest phases, seasonal living phases and
so on. I have no opinion on that.
But that is just a layman's hypothesis :-)
Regards,
Nick Maclaren.
Marc Verhaegen
news:8cfmc.6479$a47....@newsread3.news.atl.earthlink.net...
> In basic journalism you learn that there are "5 w's"; Who, What, When,
Where, & Why. Lets play a little game of journalistic reporting with the
Aquatic Ape Hypothesis.
Why not. Childs have to amuse themselves.
> Who: Some as yet undiscovered ancient ancestor of all modern humans
1) Undiscovered?? Man, a lot of Homo fossils come from coasts. Didn't you
even know this basic fact?? Inform a little bit before saying something.
2) One must be simple-minded if one believed that any fossil was an ancestor
of any living creature.
> What: Lived in and around open bodies of water (or swamps) with a
lifestyle sufficiently "aquatic" to favor the evolutionary development of
characteristics and features significantly different from our nearest
cousins (chimps) targeted specifically towards adaptation to the aquatic
environment.
Obvious, no? You don't believe that reduction of olfactory sense was a
savanna adaptation, do you?? You don't believe that flat feet are a savanna
adaptation, do you?? Etc. Etc. Etc.
> Where: Somewhere in equatorial Africa
?? Why do you believe that?? Do you have a good reason to believe this??
> When: This is a toughie. If hominid obligate bipedalism is supposedly a
product of the aquatic phase
??
Man, do you suppose this?? Nobody does, don't you know?
(Hence irrelevant blabla snipped.)
> Why: On one side I think that this might be a serious question, on the
other, the evidence is that species tend to difuse into just about any
viable ecology, so . . . . . at least the OPPORTUNITIES to difuse into
either a more watery or a much dryer environment than the primal human
ancestors can almost be assumed to be equal possibilities. Possibilities
are good for "working hypotheses", but cant be called real science. so. . .
. . lets just dump the "why" entirely!
??
Since we know that by c 1.8 Ma Homo had spread to Algeria, Kenya, Georgia,
Java, along the coasts (how else??), why wouldn't they have eaten shellfish,
crayfish, turtle & bired eggs, stranded sea mammals, coconuts etc. etc.??
Why IYHO?
Enough said??
Open your eyes, man.
Marc Verhaegen
http://www.onelist.com/community/AAT
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
Aardvark J. Bandersnatch, MP
"Bob Keeter" <rke...@earthlink.net> wrote in message
news:8cfmc.6479$a47....@newsread3.news.atl.earthlink.net...
> Where, & Why. Lets play a little game of journalistic reporting with the
> Aquatic Ape Hypothesis.
snippage
>
> And yes, Pauline, this IS a trick question! A question designed to make
you
> think some very uncomfortable thoughts (other than just that I should quit
> typing such herasy of course)! 8-) And Algis, if all of the adaptations
of
> the aquatic ape concept WERE truely unique adaptations to that watery
> environment, why have they not disappeared? AND of course, for both, if
> these "aquatic characteristics" were actually mutually advantageous in
both
> environments, why do we need to hypothesize a "different from the known"
> environment to explain their existence?
Can you say "Strawman"? I thought you could.
Jim McGinn
> As the saner readers of this group will realise, I do not buy into
> any umbrella theory,
You've bought into Langdon's silly notion that there's something
objectionable to umbrella theories and that AAT is such.
but feel that there are at least some aspects
> of the AAT that make sense. Which does not prove they are right!
> Here are a few points:
>
> The when and why (and I am happy to include that) that make most
> sense to me are the actual development of fully effective bipedalism,
> starting from a chimpanzee-like posture and movement. It is, as far
> as I know, the only hypothesis that fits all known facts and does
> not require a previous development,
Huh? What are you talking about?
with the need to explain why
> THAT happened. But there is no good evidence for it, either.
>
> I don't swallow the arguments for subcutaneous fat, hairlessness,
> etc. etc., and think that Gould has it right that most are probably
> secondary consequences of neoteny,
Neoteny is a consequence, not a cause.
which itself is explained by
> the previous development of tool use, communication and childhood
> learning.
?
>
> I have no idea where or when those (mental) skills developed, and
> could believe even the savanna, though an aquatic involvement is
> equally likely.
I've always thought it strange that anybody would bother to speculate
about habitat without linking it to a hypothesis.
The fact that most of the savanna arguments are
> completely bogus doesn't show that the WHOLE hypothesis is false.
> Current belief is that those skills are much later than bipedalism
> but, as I understand, there is little good evidence for that.
How is it not obvious that it must involve a shift in lifestyle? How
is it not obvious that this shift in lifestyle involves communalism.
>
> So I would say that the aquatic phase (assuming it occurred) was
> very early, and was the key to separating us from the other African
> great apes. I would speculate a small population being trapped in
> an area where there was not enough prey to support populations of
> the major group-hunting predators, and which was relatively
> inaccessible from where they occurred (i.e. the savanna).
About the silliest thing of all is this notion that evolution happens
in phases. Another silly notion is that small populations can
introduce trends that overtake large populations. This is tail
wagging the dog nonsense.
>
> There may have been other phases, later, just as there may have been
> savanna phases, gallery forest phases, seasonal living phases and
> so on. I have no opinion on that.
>
> But that is just a layman's hypothesis :-)
Jim
Nick Maclaren
Jim McGinn <jimm...@yahoo.com> wrote:
>
>You've bought into Langdon's silly notion that there's something
>objectionable to umbrella theories and that AAT is such.
No, I have bought into the notion that they are extremely implausible
in THIS case. Once upon a time, long before most of the users of
the Internet were born, it was unclear whether all of our unusual
characteristics developed 'together'. A vast amount of fossil
evidence now shows that to be not so.
I don't buy into an umbrella theory stretching over 3-5 million years
unless the results show a continuing adaptation to the conditions
hypothesised. I have not seen any umbrella hypothesis that meets
the requirement.
>> The when and why (and I am happy to include that) that make most
>> sense to me are the actual development of fully effective bipedalism,
>> starting from a chimpanzee-like posture and movement. It is, as far
>> as I know, the only hypothesis that fits all known facts and does
>> not require a previous development,
>
>Huh? What are you talking about?
What I said. I have posted details before, and don't intend to
repeat them in this thread.
>Neoteny is a consequence, not a cause.
Not entirely. A neotenous mutation with some selective advantage
may well introduce other neotenous characteristics as side-effects.
If those have no selective DISADVANTAGE, they may well become
dominant.
> which itself is explained by
>> the previous development of tool use, communication and childhood
>> learning.
>
>?
See Gould and many others.
>> I have no idea where or when those (mental) skills developed, and
>> could believe even the savanna, though an aquatic involvement is
>> equally likely.
>
>I've always thought it strange that anybody would bother to speculate
>about habitat without linking it to a hypothesis.
I could produce a hypothesis easily enough. In fact, I could probably
produce several for each environment, plus others. My point is that
it is POSSIBLE that a particular environment was instrumental in
developing those mental skills, but there is no obvious reason to
select that class of hypotheses above any others.
> The fact that most of the savanna arguments are
>> completely bogus doesn't show that the WHOLE hypothesis is false.
>> Current belief is that those skills are much later than bipedalism
>> but, as I understand, there is little good evidence for that.
>
>How is it not obvious that it must involve a shift in lifestyle? How
>is it not obvious that this shift in lifestyle involves communalism.
What does that have to do with the date when the development occurred?
>About the silliest thing of all is this notion that evolution happens
>in phases. Another silly notion is that small populations can
>introduce trends that overtake large populations. This is tail
>wagging the dog nonsense.
Hmm. On the first point, all fossil evidence for most taxa indicates
that major shifts do, indeed, occur in phases. There is considerable
disagreement about why.
On the second, you are no geneticist, are you?
Regards,
Nick Maclaren.
Bob Keeter
"Aardvark J. Bandersnatch, MP" <som...@micrsfot.com> wrote in message
news:fzsmc.41003$Ik.2678164@attbi_s53...
Of course I can!
. . . . . .and the Lion needed courage! The Tin Man needed a heart, and the
Strawman
only needed a brain! 8-)))) Where the heck do you think I got the seed of
my idea for the
"avian ape hypothesis"! ;-)
Seriously, a "strawman" is usually proposed as essentially an unsupported
concept, sort
of tossed out to "sink or swim". That means that a "strawman" is a
fair-game target for
criticism (else why call it a strawman)? If a fact or a question can "pull
apart" a true
strawman, the author should thank whoever presents the unsolvable dilemma,
since
it would keep the author from looking foolish for presenting a strawman for
more than
it deserved.
Now if a concept is presented as a strawman and then honored, and defended,
as if it
were devine dogma, would you not see a problem?
Can you say "hypocracy" and "intellectual honesty"? Come on, give it a
shot! ;-)
Regards
bk
Bob Keeter
"Pauline M Ross" <pmr...@ross-software.co.uk> wrote in message
news:5flj90h475tq01vq4...@4ax.com...
ACTUALLY, I have asked it before, its one of my favorites! Your answer
does give a slightly different angle to the discussion though. You would
seem
to be implying that all of modern humanity sprang from a small group of
aquatic
ancestors only 5-10kya? That would mean that either the whole line from
Sahelanthropus (or one of his contemporaries) up through the apiths, HH, HE
HN HS and HSS were ALL aquatic? I know that 18mya is a bit old for
Sahelanthropus, but if he turns out to be obligate bipedal like the apiths
and
all of homo, you do have to reach further back. . . . . .
But lets think about this a bit more. Given this "range" that you have
offered,
would you mind defining the nature of your "aquatic phase" in terms that a
dilitante such as myself might understand. At least IMHO, perhaps the most
"aquatic" of modern hominids would be the Polynesians. A major portion of
their livelihood is associated with the ocean, and has been for literally
1000's
of years. Do you see your "aquatic ancestor" as being more or less
"connected"
to the water, from an evolutionary standpoint, than a Polynesian?
Regards
bk
Jim McGinn
> >You've bought into Langdon's silly notion that there's something
> >objectionable to umbrella theories and that AAT is such.
>
> No, I have bought into the notion that they are extremely implausible
> in THIS case. Once upon a time, long before most of the users of
> the Internet were born, it was unclear whether all of our unusual
> characteristics developed 'together'. A vast amount of fossil
> evidence now shows that to be not so.
>
> I don't buy into an umbrella theory stretching over 3-5 million years
> unless the results show a continuing adaptation to the conditions
> hypothesised. I have not seen any umbrella hypothesis that meets
> the requirement.
This is a really slippery argument since nobody
knows what the other means when they use the term
umbrella. Langdon, like all anthropologists, uses
it as an excuse for ignoring standard concepts of
evolutionary biology.
>
> >> The when and why (and I am happy to include that) that make most
> >> sense to me are the actual development of fully effective bipedalism,
> >> starting from a chimpanzee-like posture and movement. It is, as far
> >> as I know, the only hypothesis that fits all known facts and does
> >> not require a previous development,
> >
> >Huh? What are you talking about?
>
> What I said. I have posted details before, and don't intend to
> repeat them in this thread.
Keep it vague, then nobody can dispute it.
>
> >Neoteny is a consequence, not a cause.
>
> Not entirely. A neotenous mutation with some selective advantage
> may well introduce other neotenous characteristics as side-effects.
> If those have no selective DISADVANTAGE, they may well become
> dominant.
Cart before the horse wishful thinking.
>
> > which itself is explained by
> >> the previous development of tool use, communication and childhood
> >> learning.
> >
> >?
>
> See Gould and many others.
Gould was clueless.
>
> >> I have no idea where or when those (mental) skills developed, and
> >> could believe even the savanna, though an aquatic involvement is
> >> equally likely.
> >
> >I've always thought it strange that anybody would bother to speculate
> >about habitat without linking it to a hypothesis.
>
> I could produce a hypothesis easily enough. In fact, I could probably
> produce several for each environment, plus others. My point is that
> it is POSSIBLE that a particular environment was instrumental in
> developing those mental skills, but there is no obvious reason to
> select that class of hypotheses above any others.
It's obvious to me that your thinking lacks
grounding in evolutionary principles.
>
> > The fact that most of the savanna arguments are
> >> completely bogus doesn't show that the WHOLE hypothesis is false.
> >> Current belief is that those skills are much later than bipedalism
> >> but, as I understand, there is little good evidence for that.
> >
> >How is it not obvious that it must involve a shift in lifestyle? How
> >is it not obvious that this shift in lifestyle involves communalism.
>
> What does that have to do with the date when the development occurred?
You lost me.
>
> >About the silliest thing of all is this notion that evolution happens
> >in phases. Another silly notion is that small populations can
> >introduce trends that overtake large populations. This is tail
> >wagging the dog nonsense.
>
> Hmm. On the first point, all fossil evidence for most taxa indicates
> that major shifts do, indeed, occur in phases.
No. It occurs during periods of climatic change.
There is considerable
> disagreement about why.
>
> On the second, you are no geneticist, are you?
You are making the classic mistake (like Crowley
recently) of extrapolating from a concept called
the founder effect. The founder effect DOES NOT
allow for this silly notion that that small
populations can introduce trends that overtake
large populations. It only tells us what happens
in small populations.
Jim
Jim McGinn
> . . . if all of the adaptations of the aquatic ape
> concept WERE truely unique adaptations to that
> watery environment, why have they not disappeared?
> AND of course, for both, if these "aquatic
> characteristics" were actually mutually advantageous
> in both environments, why do we need to hypothesize
> a "different from the known" environment to explain
> their existence?
These are killer questions, Bob! These are the kind
of common sense questions that should have been
foremost on the minds of anybody considering an
aquatic hypothesis. But you won't get a response from
Algis, Pauline, or Marc on any of this. And this is
because their understanding of NS has little if
anything to do with common sense.
Jim
Jim McGinn
> That means that a "strawman" is a fair-game target
> for criticism (else why call it a strawman)? If a
> fact or a question can "pull apart" a true
> strawman, the author should thank whoever presents
> the unsolvable dilemma, since it would keep the
> author from looking foolish for presenting a
> strawman for more than it deserved.
Maybe I'm missing your meaning here Bob, but a
"strawman," is a rhetorical tactic in which a person
misrepresents their opponents thinking with a weaker
version thereof and then proceeds to tear it down,
thus creating the illusion that their opponents
position is much weaker than it really is. (But on
second reading I think you already understand this
and are saying something altogether different.)
(One of the tactics of the conventional theorists in
this NG--and in PA in general--is to keep their own
thinking/hypothesis so vague that any attempt at all
to by their opponents to represent their
thinking/hypothesis--no matter how much they might
genuinely wish to avoid it--results in the strawman
accusation.)
Jim
Bob Keeter
Snippage. . . ..
> > Seriously, a "strawman" is usually proposed as essentially an
unsupported
> > concept, sort of tossed out to "sink or swim". That means that a
"strawman"
> > is a fair-game target for criticism (else why call it a strawman)? If a
fact or
> > a question can "pull apart" a true strawman, the author should thank
whoever
> > presents the unsolvable dilemma, since it would keep the author from
looking
> > foolish for presenting a strawman for more than it deserved.
>
> WRONG. Try again.
>
8-) OK, what would you call a "strawman"? Let me guess, its a revelation
from
on high delivered to a disciple of the true science, needing no proof,
evidence or
logic other than his personal decree! 8-) And of course, anyone who would
take
issue with a "strawman" proposal is an obvious heretic worthy of a hot stake
or a
cold chop! 8-0
> >
> > Now if a concept is presented as a strawman and then honored, and
> > defended, as if it were devine dogma, would you not see a problem?
> >
> > Can you say "hypocracy" and "intellectual honesty"? Come on, give it a
> > shot! ;-)
>
> PS-- your spelling suxrox.
Ah, yes. Spelling is it! 8-) Injuneers aint gotta be literat! But then
again
I dont have any trouble spelling my own name! But then I guess thats a
symptom of something other than simply not having the spell checker turned
on! 8-))
regards
bk
Pauline M Ross
wrote:
>You would seem to be implying that all of modern humanity sprang from a small group of
>aquatic ancestors only 5-10kya?
Why a small group? I would say that *all* modern humans are/were
'aquatic' (see definition below).
> That would mean that either the whole line from
>Sahelanthropus (or one of his contemporaries) up through the apiths, HH, HE
>HN HS and HSS were ALL aquatic? I know that 18mya is a bit old for
>Sahelanthropus, but if he turns out to be obligate bipedal like the apiths
>and all of homo, you do have to reach further back. . . . . .
Yep, that's it, more or less. Not that there weren't some hominids who
may have been less (or not at all) 'aquatic' (see definition below),
but our ancestors were consistently 'aquatic'.
>
>But lets think about this a bit more. Given this "range" that you have
>offered, would you mind defining the nature of your "aquatic phase" in terms that a
>dilitante such as myself might understand. At least IMHO, perhaps the most
>"aquatic" of modern hominids would be the Polynesians. A major portion of
>their livelihood is associated with the ocean, and has been for literally
>1000's of years. Do you see your "aquatic ancestor" as being more or less
>"connected" to the water, from an evolutionary standpoint, than a Polynesian?
OK, let's define 'aquatic' first: when I use the word 'aquatic' in the
context of human evolution, I mean that water was an inescapable part
of our ancestors' lives, and not just for drinking. Either there was
so much of it about that they had to wade and/or swim just to get
about, or that they got a substantial part of their food by physically
getting in the water. But naturally they also continued to move about
on land and use terrestrial resources.
Now this is less 'aquatic' than a dolphin (they were never in water
all the time) and less 'aquatic' than an otter or a seal (they were
never totally dependent on aquatic resources). Nevertheless, they were
sufficiently 'aquatic' for a long enough time to account for the
peculiarities we see in modern humans. In my opinion, anyway.
As to the Polynesians, I would say that the ancestral condition was
more 'aquatic' than that, since all modern humans are so adept with
tools that we never need to get in the water at all now - if we want
fish, we get out the boat, nets and hooks, or we can hunt land mammals
instead. The whole history of Homo has been the steady development of
tools which protect us from physical contact with our environment
(including water), so we have become somewhat less 'aquatic' with
time, but still sufficiently 'aquatic' that modern humans dispersed
all round the world by coastal routes and boats.
So no 'aquatic phase' as such, just a very long history of close
association with water, ending only very recently.
--
Pauline Ross
Aardvark J. Bandersnatch, MP
"Jim McGinn" <jimm...@yahoo.com> wrote in message
news:ac6a5059.04050...@posting.google.com...
> "Bob Keeter" <rke...@earthlink.net> wrote
>
> > That means that a "strawman" is a fair-game target
> > for criticism (else why call it a strawman)? If a
> > fact or a question can "pull apart" a true
> > strawman, the author should thank whoever presents
> > the unsolvable dilemma, since it would keep the
> > author from looking foolish for presenting a
> > strawman for more than it deserved.
>
> Maybe I'm missing your meaning here Bob, but a
> "strawman," is a rhetorical tactic in which a person
> misrepresents their opponents thinking with a weaker
> version thereof and then proceeds to tear it down,
> thus creating the illusion that their opponents
> position is much weaker than it really is. (But on
> second reading I think you already understand this
> and are saying something altogether different.)
BINGO!
Here, have a gold star.
Bob Keeter
> On Thu, 06 May 2004 22:44:54 GMT, "Bob Keeter" <rke...@earthlink.net>
> wrote:
>
> >You would seem to be implying that all of modern humanity sprang from a
small group of
> >aquatic ancestors only 5-10kya?
>
> Why a small group? I would say that *all* modern humans are/were
> 'aquatic' (see definition below).
>
> > That would mean that either the whole line from
> >Sahelanthropus (or one of his contemporaries) up through the apiths, HH,
HE
> >HN HS and HSS were ALL aquatic? I know that 18mya is a bit old for
> >Sahelanthropus, but if he turns out to be obligate bipedal like the
apiths
> >and all of homo, you do have to reach further back. . . . . .
>
> Yep, that's it, more or less. Not that there weren't some hominids who
> may have been less (or not at all) 'aquatic' (see definition below),
> but our ancestors were consistently 'aquatic'.
Who knows! I may have trotted out one of the good Mr. Bandersnatch's
"strawmen" and didnt even know it! Well, Duh! 8-)
Snippage. . .
> OK, let's define 'aquatic' first: when I use the word 'aquatic' in the
> context of human evolution, I mean that water was an inescapable part
> of our ancestors' lives, and not just for drinking. Either there was
> so much of it about that they had to wade and/or swim just to get
> about, or that they got a substantial part of their food by physically
> getting in the water. But naturally they also continued to move about
> on land and use terrestrial resources.
So, all along since pre-Sahelanthropus days, we were tied to
open/flowing/standing bodies of water, but as you say, they would
continue to move about on land and also feed on terrestrial sources
right? Now that feels a LOT like what I would call a semi-aquatic
species, and there are plenty of precidents for said lifestyle among
mammals! At one end of the continuum, you might find an Alaskan
brown bear. The bear depends on the salmon runs for a major portion
of the stored fat that will get it through the winter, however for probably
90-95% of the time, its out on try land (eating or hybernating). Couldnt
survive without the salmon runs, but only has spawing salmon for a very
few weeks out of the year. On the other extreme is the N. American
beaver. It spends probably 70-75% of its time in the water but its food
is almost entirely found on the land (except for a little touch of algae
during the spring).
So lets take this WHOLE spectrum of semi-aquatic mammalian
species and lets look at how many of the "aquatic ape" characteristics
they share!
Some rhetorical questions!
Are any obligate bipeds?
Are any even semi-hairless?
Do any have significant layers of SC fat for insulation OR bouyancy?
Given your own answers, is there any justification to include a hominid
in this category?
> Now this is less 'aquatic' than a dolphin (they were never in water
> all the time) and less 'aquatic' than an otter or a seal (they were
> never totally dependent on aquatic resources). Nevertheless, they were
> sufficiently 'aquatic' for a long enough time to account for the
> peculiarities we see in modern humans. In my opinion, anyway.
So, less aquatic than cetaceans (i'll toss in sirenians if you dont mind),
and
even less aquatic than a seal or an otter. Hmmmmm. So we have narrowed
the degree of aquaticism to the otter on one end and perhaps my brown bear
on the other?
Same rhetorical questions. . . . . . . 8-)
> As to the Polynesians, I would say that the ancestral condition was
> more 'aquatic' than that, since all modern humans are so adept with
> tools that we never need to get in the water at all now - if we want
> fish, we get out the boat, nets and hooks, or we can hunt land mammals
> instead. The whole history of Homo has been the steady development of
> tools which protect us from physical contact with our environment
> (including water), so we have become somewhat less 'aquatic' with
> time, but still sufficiently 'aquatic' that modern humans dispersed
> all round the world by coastal routes and boats.
>
> So no 'aquatic phase' as such, just a very long history of close
> association with water, ending only very recently.
So, the "aquatic period" ended with the advent of tools?"
Yep, I like those rhetorical questions! I think that perhaps putting you
in the position to have to think through this little proposition of yours is
my best "debating tactic"! After all, I cant convince you that the aquatic
ape theory is hogwash, you must do that for me! ;-)
Regards
bk
Pauline M Ross
wrote:
[Snip discussion of beavers and bears]
>So lets take this WHOLE spectrum of semi-aquatic mammalian
>species and lets look at how many of the "aquatic ape" characteristics
>they share!
[Snip]
>Are any obligate bipeds?
>Are any even semi-hairless?
>Do any have significant layers of SC fat for insulation OR bouyancy?
And are any of them tropical? Arboreal? Primates? Hominid-sized? To
get from A to B, you first have to start at A.
>>[Pauline]The whole history of Homo has been the steady development of
>> tools which protect us from physical contact with our environment
>> (including water), so we have become somewhat less 'aquatic' with
>> time, but still sufficiently 'aquatic' that modern humans dispersed
>> all round the world by coastal routes and boats.
>> So no 'aquatic phase' as such, just a very long history of close
>> association with water, ending only very recently.
>
>So, the "aquatic period" ended with the advent of tools?"
The advent of tools was (at least) 2.5 Mya, possibly substantially
earlier. I date the end of the 'aquatic period' to the start of
agriculturalism (say 10 kya). Bit different. But it isn't a
black-and-white thing; the more sophisticated the tools became, the
more our ancestors were capable of breaking away from the water (but
the most successful groups were always those who stayed close to it -
until recently).
>
>Yep, I like those rhetorical questions! I think that perhaps putting you
>in the position to have to think through this little proposition of yours is
>my best "debating tactic"! After all, I cant convince you that the aquatic
>ape theory is hogwash, you must do that for me! ;-)
I'm still waiting for that hogwash-proving piece of evidence :-)
--
Pauline Ross
Marc Verhaegen
Sigh. Keeter is producing his usual biases.
On semi-aquatics, he asks:
> >Are any obligate bipeds?
1) ?? I hope Keeter doesn't use this against AAT?? (You never know the
prejudices of these people...)
2) Kangaroos are obligate bipeds. Yes, kangaroos could be called
savanna-dwellers... No doubt this proves humans descend from
savanna-dwellers... :-D
3) IMO human bipedalism results from having dwelt in flooded forests
(wading-suspensory) followed by coastal swimming-wading-walking.
4) Penguins walk on land vertically like humans (straight bodies).
> >Are any even semi-hairless?
Keeter apparently doesn't realise that tropical coastal mammals smaller than
babirusas & humans don't lose the fur. What is he trying to say? That humans
can't have had coastal ancestors??
> >Do any have significant layers of SC fat for insulation OR bouyancy?
Keeter seems to believe that SC fat must have been for buoyancy?? Doesn't he
know that our coastal ancestors had to find shellfish not at the surface,
but at the bottom?? I don't know what he is arguing.
(It's "buoyancy" AFAIK. Keeter should at least try to spell his own language
correctly (not difficult: the man could use a dictionary, as I have to do so
often: I already have the handicap of having to write a foreign language).)
> >>[Pauline]The whole history of Homo has been the steady development of
tools which protect us from physical contact with our environment (including
water), so we have become somewhat less 'aquatic' with time, but still
sufficiently 'aquatic' that modern humans dispersed all round the world by
coastal routes and boats. So no 'aquatic phase' as such, just a very long
history of close association with water, ending only very recently.
> >So, the "aquatic period" ended with the advent of tools?"
?? Why does he believes that?? It's difficult to follow the curious
reasonings of these people.
> The advent of tools was (at least) 2.5 Mya, possibly substantially
earlier.
Yes, not unlikely. Since orangs use & make tools, this could even predate
the hominid-pongid LCA c 15 Mya or so.
> I date the end of the 'aquatic period' to the start of agriculturalism
(say 10 kya).
Yes. And even then: rice grows in shallow water.
> Bit different. But it isn't a black-and-white thing; the more
sophisticated the tools became, the more our ancestors were capable of
breaking away from the water (but the most successful groups were always
those who stayed close to it - until recently).
Well-said, Pauline.
Rest of Keeter's blabla snipped.
Bob Keeter
> On Sat, 08 May 2004 02:15:30 GMT, "Bob Keeter" <rke...@earthlink.net>
> wrote:
>
> [Snip discussion of beavers and bears]
> >So lets take this WHOLE spectrum of semi-aquatic mammalian
> >species and lets look at how many of the "aquatic ape" characteristics
> >they share!
> [Snip]
> >Are any obligate bipeds?
> >Are any even semi-hairless?
> >Do any have significant layers of SC fat for insulation OR bouyancy?
>
> And are any of them tropical? Arboreal? Primates? Hominid-sized? To
> get from A to B, you first have to start at A.
>
I swear, I did not hold up a cue card! 8-)
So yo say that there are no arboreal, hominid-sized, semi-aquatic
species in the primate line? 8-) You have GOT to admit that is
at least ONE way to read your statement! You could claim a
bad interpretation, I could claim a Freudian slip! 8-) Enough
with the word games though. . . . . . ..
Lets start from the right and move to the left!
Hominid sized: YES! Matter of fact!
We have the giant river otter of the South American river
basins (orinoco and amazon). I believe that it qualifies as both roughly
hominid (apith) sized, and tropical! In length, the otter is quite a bit
"longer, leaner and more streamlined" and the apith is a bit more solidly
built.
http://www.seaworld.org/AnimalBytes/giantriverotter.htm
Males weigh 26-34 kg, females weigh 22-26 kg
Head & body length = 864 - 1,400 mm
Tail length = 330 - 1,000 mm
so, counting the very substancial tail up to 2.4 meters
and
http://www.modernhumanorigins.com/anamensis.html
"Specimens from other sites such as Sibilot Hill also may be anamensis, but
there is much debate on the validity of the anamensis species, since the
samples are very close in morphology to afarensis. One factor that seems to
separate anamensis and afarensis is the mean body weight of the male
specimens. The mean of Hadar afarensis specimens is 44.6 kg, but the body
weight estimates for the tibia (KP 29285) is approximately 55 kg, and
approximately 58 kg for the humerus (KP 271). These weights were estimated
using McHenry's predictive regression equations. "
And if I remember correctly A. africanus and A. afarensis are both right at
1.5m in height for the males (more like 1-1.25 for the females), correct me
if Im wrong, but with a body length (less tail) of .864 to 1.4 meters, Id
say that the river otter is a fair match. Again though, the otter is
required to swim for its dinner (and survival) so. . . . . longer, leaner,
more streamlined and as furry as a little teddy bear! 8-)
www.wwfguianas.org/ feat_spec_giant_otter.htm
By the way, if you go to Google and search the images for "giant river
otter" you can find several nice pictures of these sleekly furred, tropical,
semi-aquatic mammals sitting in trees! They are NOT great climbers by any
means, but. . .
in trees = arboreal (to some degree or less). If we used the same standard
of "time spent" in an environment that Algis used for his aquatic bonobos, I
think that a single picture of a giant river otter sitting on a tilted tree
bole is more than adequate for "arboreal" dont you?
Snipapge. . . . . . .
> >So, the "aquatic period" ended with the advent of tools?"
>
> The advent of tools was (at least) 2.5 Mya, possibly substantially
> earlier. I date the end of the 'aquatic period' to the start of
> agriculturalism (say 10 kya). Bit different. But it isn't a
> black-and-white thing; the more sophisticated the tools became, the
> more our ancestors were capable of breaking away from the water (but
> the most successful groups were always those who stayed close to it -
> until recently).
Just so that there is no mistake, I also believe that the advent of tools
was a VERY important point in human evolution (and apparently for
basically the same reason, i.e. it marked the start of technological
evolution being a significant (principal?) factor in human evolution vs.
a purely biological evolution. I suspect that the ONLY difference
in our points of view is the starting point for this technologically driven
hominid evolution. See, perhaps more agreement than either might
have thought! 8-)
Im even of the mind to suggest that the big technological "jump" that
emancipated early hominids from the need to be close to (drinking)
water was the water skin or canteen. Chimps use tools (at least sticks
and twigs and nut-cracking rocks) but they dont have any way to
carry water. If you could give a chimp a canteen and train him to
use it, exactly what would he be missing in terms of evolutionary
and technological adaptations to move out into the true grasslands?
Remember, the ones that live in the deep forest dont need canteens
or even rivers and streams because of their diet and the readily available
sources in a rain forest. The ones that live outside of a rain forest need
to stay
reasonably close to a drinking water supply, even though that water
source does not really supply a great deal of their food. Give them a
canteen
and where are the "limits"?
> >
> >Yep, I like those rhetorical questions! I think that perhaps putting you
> >in the position to have to think through this little proposition of yours
is
> >my best "debating tactic"! After all, I cant convince you that the
aquatic
> >ape theory is hogwash, you must do that for me! ;-)
>
> I'm still waiting for that hogwash-proving piece of evidence :-)
>
Oh, I dont think that either of us will know its arrived until YOU
say so! Best I can do is to keep gnawing away at those linchpins
of the quivering/rock-solid (depending on point of view) AAH
and offering up difficult questions! 8-)
. . . . . even ill educated termites can bring down tall buildings if
they are diligent enough in their gnawing! Not of course that I
would say AAH is exactly a "tall building"! Sorta low lying and
short of structural support. . . . . . ;-)
Regards
bk
Algis Kuliukas
> Where, & Why. Lets play a little game of journalistic reporting with the
> Aquatic Ape Hypothesis.
[..]
> So, lets go back to where there is some fat to be chewed, to a question for
> the entire AAH community! WHEN would you say that your evolutionarily
> significant aquatic phase occurred for ancestoral hominids? How far back to
> you put it to allow it to be the genesis of human style bipedalism, without
> putting it so far back that any uniquely aquatic impacts on our current
> physiology would have simply disappeared? Or is bipedalism simply a non
> sequitur with respect to the aquatic ape concept.
>
> Think timeline! 8-) Need a timeline that makes sense when viewed from both
> ends and from the middle
In my opinion there was no single distinct 'aquatic phase' as such.
This is the one part of the original Hardy/Morgan hypothesis (ie a
post Pan-Homo LCA, pre Homo real aquatic phase) that Langdon did do a
good job of refuting - if only to point out that a'piths are hardly
indicative of being more aquatic than humans are which they should
have been if a real phase had happenned around 6mya.
I currently think human evolution was probably an extremely complex
mosaic of short, localised phases when our ancestors were generally
exposed to more aquatic pressures and then phases when they were
exposed to greater terrestriality. I think Potts' (1998) case for the
variable selection hypothesis is actually very close to the mark, when
he proposes that it wasn't so much the generally accepted shift
towards aridity which shaped humans but an increase in the frequency
of change cycles from wet to dry and then back again which was a
driver in itself. The point he misses, though, in my opinion is that
in periods of aridity the forests and dependent fauna would certainly
retreat back to gallery forest refugia and in periods of wetness
they'd be more exposed to flooding and drowning. It's the instability
of the habitat, specifically from the point of view of water, which
forced them ever closer to water when it was dry and required them to
move through it better when it was wet. As a consequence our ancestors
would have been exposed, in small cyclic steps, ever towards greater
aquaticism - but never quite getting there. This series of
aridity-flood cycles probably started way back in the Miocene, could
well have been due to the major waves of hominids moving out of Africa
and almost certainly ended only very recently (< 50ky) causing the
final, most recent migrations of the OoA II exodus.
Potts, Richard (1998). Environmental Hypotheses of Hominin Evolution.
Yearbook of Physical Anthropology Vol:41 Pages:93-136
I think the timescale was a complex mosaic and so was the geography -
some hominids living in being lake-side, some riverside, some coastal
and some island-based - and also, probably, it wasn't just on one
lineage. I think the likelihood is that there was a fair degree of
introgression (hybridisation) in hominid evolution, meaning that
whilst one population might have been going through a 'more aquatic'
phase, another may have been simultaneously going trough a
particularly terrestrial one. One might expect that the hybrids of
such groups would leave a perplexing mix of traits that look odd to us
today, to say the least, and do not easily fit easily next to simple
mammalian analalogues.
Only an opinion. Only thinking aloud - but we're allowed to do that
here, aren't we?
Algis Kuliukas
Bob Keeter
"Algis Kuliukas" <al...@RiverApes.com> wrote in message
news:77a70442.04050...@posting.google.com...
So would you say that whatever "aquatic adapations" that are present
were done by the time of the apiths? If so, you have a bit of a problem I
think. Lets just say, hypothetically of course, that the notional
adaptations
were inspired by a pre-Apith period of more intensive "aquaticism". Since
the advent of the Apiths though, we have have been just about stable in
terms of major body "adaptations". The movement towards bigger brains
than our ape ancestors was well on the way; bipedalism was an extablished
fact, knuckle walking was a thing of the past, and climbing was apparently
if not a dying art, at least less important than with earlier primates. Now
lets roll in "aquatic adaptations". The curved fingers that seem to betray
a very recent, or even current arboreal present for the apiths, disappear in
future evolution! Its not so much that curved finger bones are all that
disadvantageous for future uses of the hands as much as there simply isnt
the need for them (and perhaps there is a different kind of "loading" that
influences the bone growth during life without any genetic influence).
Anyway you look at it though, those curved finger bones of an
arborealist simply disappear. Yet you would have us believe that
adaptations that are totally anthithetical to an upright, terrestrial
existence would persist right through the Apiths into modern humans?
Hmmmmm.. How is it that the tree climbing adaptations disappeared
yet the aquatic persisted (even though some of the subtle ones like the
curvature of the filanges were "dont cares" with no reason to see
as a disadvantage to a species no longer tied to the trees?)?
Again, I have to ask, if the hypothetical adaptations for the aquatic
environment were RETAINED in the modern, non-aquatic phase,
does that not imply at least SOME advantage to those adaptations
in the current environments? Now we will do one of those
"If A, then B" exercises. . . . . If the adaptations were favorable enough
in the terrestrial existence to have been retained, what is to say that they
did not develop in the terrestrial environment as well? 8-)
> I currently think human evolution was probably an extremely complex
> mosaic of short, localised phases when our ancestors were generally
> exposed to more aquatic pressures and then phases when they were
> exposed to greater terrestriality. I think Potts' (1998) case for the
> variable selection hypothesis is actually very close to the mark, when
> he proposes that it wasn't so much the generally accepted shift
> towards aridity which shaped humans but an increase in the frequency
> of change cycles from wet to dry and then back again which was a
> driver in itself. The point he misses, though, in my opinion is that
> in periods of aridity the forests and dependent fauna would certainly
> retreat back to gallery forest refugia and in periods of wetness
> they'd be more exposed to flooding and drowning. It's the instability
> of the habitat, specifically from the point of view of water, which
> forced them ever closer to water when it was dry and required them to
> move through it better when it was wet. As a consequence our ancestors
> would have been exposed, in small cyclic steps, ever towards greater
> aquaticism - but never quite getting there. This series of
> aridity-flood cycles probably started way back in the Miocene, could
> well have been due to the major waves of hominids moving out of Africa
> and almost certainly ended only very recently (< 50ky) causing the
> final, most recent migrations of the OoA II exodus.
Personally, Im thinking that Potts didnt miss much at all! The ONE
characteristic
of hominids that I firmly believe sets us appart from all other terrestrial
species is our adaptability! We are the ONLY primate with a range
from the deep tropic rain forest to the frozen tundra (and we and our
ancestors had occupied much if not all of that range well before the
development of even Neolythic technologies!) But that does not get us
upright and hairless striding across the grassy veld now does it! 8-)
Actually, I think that a quick look at modern climatic instabilities give
us a very good clue. Large parts of Africa seem to swing between
open forest, scrubland, grassland and even desert with major impacts on
human habitation. Look at the petroglyphs of the Atlas mountains and
the pre-desertification inhabitants of the Sahara, or in more recent times
the droughts that have ravished the Sahel. In the past there would have
been no relief columns and water trucks, just a very rapid and totally
uncaring "selection" for those species that could survive in a dry climate.
Now that small handfull that managed (through whatever trick or skill),
would need to retain the ability to exist in a wetter environment when
the monsoons retained (not nearly so hard as that first transition), but
thats my $0.02 and I havent seen a lot to convince me otherwise,
how about you? 8-)
Snippage. . . .
> I think the timescale was a complex mosaic and so was the geography -
> some hominids living in being lake-side, some riverside, some coastal
> and some island-based - and also, probably, it wasn't just on one
> lineage. I think the likelihood is that there was a fair degree of
> introgression (hybridisation) in hominid evolution, meaning that
> whilst one population might have been going through a 'more aquatic'
> phase, another may have been simultaneously going trough a
> particularly terrestrial one. One might expect that the hybrids of
> such groups would leave a perplexing mix of traits that look odd to us
> today, to say the least, and do not easily fit easily next to simple
> mammalian analalogues.
Unless of course, that all of the "traits" have some explaination that
so far eludes us (or perhaps only eludes some of us! Exactly which "some"
is
yet to be seen of course! ;-) )
> Only an opinion. Only thinking aloud - but we're allowed to do that
> here, aren't we?
Hey, thinking outloud, so long as its thinking and not just some of the
name calling and childish tantrums that certain elements tend to bring
to these happy folds is more than welcome. As for those malcontent,
malevolent little people that have to play ego games, silence is golden!
8-)
Regards
bk
Algis Kuliukas
I think you must have misread what I wrote, Bob. If you read the above
para and the rest below you'll see that I don't think anything of the
sort. If anything more aquatic pressre happenned after the A'piths in
my opinion.
Pauline M Ross
wrote:
>>[Pauline] And are any of them tropical? Arboreal? Primates? Hominid-sized? To
>> get from A to B, you first have to start at A.
>[Bob]So yo say that there are no arboreal, hominid-sized, semi-aquatic
>species in the primate line? 8-) You have GOT to admit that is
>at least ONE way to read your statement!
No, sorry, don't see that at all :-(
>Hominid sized: YES! Matter of fact!
>We have the giant river otter of the South American river
>basins (orinoco and amazon). I believe that it qualifies as both roughly
>hominid (apith) sized, and tropical! In length, the otter is quite a bit
>"longer, leaner and more streamlined" and the apith is a bit more solidly
>built.
OK, nice example. I'll come back to the giant otter and his cousins in
a minute. Let's take the general points first.
>> >[Bob]So lets take this WHOLE spectrum of semi-aquatic mammalian
>> >species and lets look at how many of the "aquatic ape" characteristics
>> >they share!
>> [Snip]
>> >Are any obligate bipeds?
No. If you are saying that a semi-aquatic lifestyle per se does not
result in bipedalism, I would agree with you. Water *alone* will not
do it.
The problem is that bipedalism is vanishingly rare in the entire
history of our planet - only dinosaurs, birds and a rather small
number of hopping, leaping things. So there are very few points of
comparison, which are either very different from us or are extinct.
But (as I was *trying* to point out up above!) it depends where you
start from - most terrestrial species (and virtually all mammals) are
solidly quadrupedal, and that's not a good starting point for
bipedalism, whether water is involved or not. Being arboreal (and
therefore being used to an upright body) is a much better starting
point. Even so, most arboreals are quadrupedal on the ground, and even
those which wade bipedally are still mostly quadrupedal on dry land.
So even though water can get an ape walking bipedally, it will take
more than that to convert him to *obligate* bipedalism.
>> >Are any even semi-hairless?
Hippos, of course, and the largest pinnipeds. But the hairless thing
is a whole can of worms. The full-time aquatics are all hairless (so
hairlessness clearly has some connection with aquaticism), but most
semi-aquatics are not, and then you get some terrestrial species
(elephants, rhinos, pigs) which are hairless but not aquatic (we can
ignore the burrowers, which I think we can agree have no relevance for
human evolution).
Of the semi-aquatics, the vast majority are polar or sub-polar (of the
pinnipeds, for instance, I believe only 3 species are found in warm
waters). Generally, they are carnivores who spend most of their time
out of water resting. This means that their fur is still useful.
As for your otters, there are some 13 different species, and most are
subpolar and quite small. However, there are several tropical species,
and the giant otter is certainly hominid-sized.
As I say, the reasons for mammals to lose their fur are complex, and
there seem to be correlations with aquaticism, body size, local
temperature and lifestyle, but there isn't an easy answer.
>> >Do any have significant layers of SC fat for insulation OR bouyancy?
Yes, the pinnipeds (and possibly some otters, but I haven't been able
to nail that down definitively). Actually, I can't think of any
species with permanent fat which is *not* aquatic.
I'm not trying to say that we *must* have been 'aquatic' because we
have no fur or subcutaneous fat or whatever; only that these things
*may* be connected with water and therefore that that should be
considered as one of options.
>Just so that there is no mistake, I also believe that the advent of tools
>was a VERY important point in human evolution
[Snip]
>Im even of the mind to suggest that the big technological "jump" that
>emancipated early hominids from the need to be close to (drinking)
>water was the water skin or canteen.
I have this image in my mind of your hominids striding out bipedally
with their water skins, and the males with their clubs, and the
females with their infants, and perhaps carrying a few stone tools as
well - my goodness, they had their hands full ;-)
>. . . . . even ill educated termites can bring down tall buildings if
>they are diligent enough in their gnawing! Not of course that I
>would say AAH is exactly a "tall building"! Sorta low lying and
>short of structural support. . . . . . ;-)
Another great image! Gnaw away, termite :-)
--
Pauline Ross
Bob Keeter
"Algis Kuliukas" <al...@RiverApes.com> wrote in message
Snip. . .
> > > In my opinion there was no single distinct 'aquatic phase' as such.
> > > This is the one part of the original Hardy/Morgan hypothesis (ie a
> > > post Pan-Homo LCA, pre Homo real aquatic phase) that Langdon did do a
> > > good job of refuting - if only to point out that a'piths are hardly
> > > indicative of being more aquatic than humans are which they should
> > > have been if a real phase had happenned around 6mya.
>
> > So would you say that whatever "aquatic adapations" that are present
> > were done by the time of the apiths? If so, you have a bit of a
problem I
> > think.
>
> I think you must have misread what I wrote, Bob. If you read the above
> para and the rest below you'll see that I don't think anything of the
> sort. If anything more aquatic pressre happenned after the A'piths in
> my opinion.
Hey, this is good! we now have at least one "limit" in there for your
particular concept of the AA! If most of the "aquatic pressures" were
after the time of the apith, that would mean that bipedalism would
necessarily be "off the table" as a characteristic primarily driven by
aquatic factors, wouldnt it?
Among the various "aquatic adaptations", obligate bipedalism is the
feature that requires the most "moving around" of skeletal structure
and therefore would be the most tediously evolved of the lot,
at least IMHO. We can demonstrate from the archeological
evidence that the human physique can "move around" quite a bit
within limits (Equadorean highlanders being one of the prime
examples) quite quickly from an evolutionary standpoint. These
adaptations though did not change the basic structure of a human
being, they just did things like reduce arm and leg length, increase
lung capacity, increase hemoglobin levels in the blood, etc (all
adaptations for high altitude almost certainly occuring since
the initial influx of HS into the Americans! Obligate bipedalism
changed the way the bones go together, I would propose a
MUCH longer and MUCH more involved process that would
have left significant indications in the fossil material between
the Apiths and today (unless of course the Apiths are accepted
to already be obligate, or nearly-obligate bipeds!)
Regards
bk
Bob Keeter
Thank you ma'am!
> The problem is that bipedalism is vanishingly rare in the entire
> history of our planet - only dinosaurs, birds and a rather small
> number of hopping, leaping things. So there are very few points of
> comparison, which are either very different from us or are extinct.
>
I would say that the hopping, leaping things are different enough to
also exclude, making your statement even more emphatically true!
> But (as I was *trying* to point out up above!) it depends where you
> start from - most terrestrial species (and virtually all mammals) are
> solidly quadrupedal, and that's not a good starting point for
> bipedalism, whether water is involved or not. Being arboreal (and
> therefore being used to an upright body) is a much better starting
> point. Even so, most arboreals are quadrupedal on the ground, and even
> those which wade bipedally are still mostly quadrupedal on dry land.
> So even though water can get an ape walking bipedally, it will take
> more than that to convert him to *obligate* bipedalism.
We have some significant points of agreement I think. but its not
terribly interesting for me to tell you that you are a genius and for
you to return the favor! ;-)
So you say rather conclusively that "water can get an ape walking
bipedally". Does that mean that an ape can not and will not
wade other than bipedally? Most apes are sometimes bipedal
sometimes quadrupedal, both on land and in the water, would
you not agree? Most apes are not "aquatic", at least not if that
is one of the "separators" between us and the rest of them, right?
If a non-aquatic still wades (bipedally or quadrupedally) how do
we define "aquatic"?
> >> >Are any even semi-hairless?
>
> Hippos, of course, and the largest pinnipeds. But the hairless thing
> is a whole can of worms. The full-time aquatics are all hairless (so
> hairlessness clearly has some connection with aquaticism), but most
> semi-aquatics are not, and then you get some terrestrial species
> (elephants, rhinos, pigs) which are hairless but not aquatic (we can
> ignore the burrowers, which I think we can agree have no relevance for
> human evolution).
Yep! We have very big terrestrial and hairless, we have completely
aquatic and hairless, we have very big and semi-aquatic (verging on
fully aquatic, like the walruses) andd we have burrowing and hairless.
None works as an example! We agree!!! Except, for one small point.
What "semiaquatic" that is less than one order of magnitude heavier
than any hominid is hairless? Hippos are heavy enough to be considered
in the same breath as elephants and rhinos, relatively hairless
terrestrials!
Giant otters and many seals are the right general size and are definitely
aquatic to one degree or another, but all are furry critters.
Is there a semi-aquatic, less than 1500 lbs, that does not have DENSE
fur?
> Of the semi-aquatics, the vast majority are polar or sub-polar (of the
> pinnipeds, for instance, I believe only 3 species are found in warm
> waters). Generally, they are carnivores who spend most of their time
> out of water resting. This means that their fur is still useful.
>
Woops! Are you REALLY saying that fur seals spend most of their time out
of the water?
> As for your otters, there are some 13 different species, and most are
> subpolar and quite small. However, there are several tropical species,
> and the giant otter is certainly hominid-sized.
>
> As I say, the reasons for mammals to lose their fur are complex, and
> there seem to be correlations with aquaticism, body size, local
> temperature and lifestyle, but there isn't an easy answer.
>
OK, one of the "tricks" of formal logic is to take a difficult question and
try
to disprove the converse of the question. Ive tried that a little bit
abstractly
elsewhere in this tread. What if we took an alternate, opposite hypothesis.
In this case, lets propose that hairlessness is NOT a characterisic of
semi-aquatic
mammals with less than 1500 lbs of body mass. Now, if you can provide one
example, you have conclusively disproven that statement! (since the question
of
the aquaticism of homo is the real question, that particular "example" is of
course
off base unless you wish to open up to charges of circular logic.)
I'll warn you, if you find an example, I will drop the weight to 500lbs and
ask again!
The real point of course is that there are no 100 lb hairless semi-aquatics
in mammalia!
Very easily disprovable, although virtually impossible to prove! Go for it!
or of course, if you choose to concede that point, thats OK too! ;-)
> >> >Do any have significant layers of SC fat for insulation OR bouyancy?
>
> Yes, the pinnipeds (and possibly some otters, but I haven't been able
> to nail that down definitively). Actually, I can't think of any
> species with permanent fat which is *not* aquatic.
Would you add "fully aquatic", or "completely aquatic"?
One real example, albeit not "permanent" would be the Kodiak brown
bears that put on a huge layer of fat snacking on the salmon runs, but the
purpose of that fat is patently obvious (i.e. food storage for the winter
hybernation). Anything that interferes with the acquisition of this yearly
nutritional storehouse could easily kill the giant bears! So. . . we have
an
example of a semi-permanent fat layer for nutritional purposes. . . . Hmmmm
> I'm not trying to say that we *must* have been 'aquatic' because we
> have no fur or subcutaneous fat or whatever; only that these things
> *may* be connected with water and therefore that that should be
> considered as one of options.
Pauline, being considered is one thing, being accepted and embraced
is another entirely! You consider them. Do you honestly think that our
current nearly hairless condition was driven by a need to cut aquatic
friction? Do you honestly believe that SC fat in humans was driven by
a need for floation and aquatic insulation rather than as a store of
high quality nutrition for the early infant development? If so, say
so. If not, dont waffle around trying to protect AAH arguements. Its
very unbecoming.
> >Just so that there is no mistake, I also believe that the advent of tools
> >was a VERY important point in human evolution
> [Snip]
> >Im even of the mind to suggest that the big technological "jump" that
> >emancipated early hominids from the need to be close to (drinking)
> >water was the water skin or canteen.
>
> I have this image in my mind of your hominids striding out bipedally
> with their water skins, and the males with their clubs, and the
> females with their infants, and perhaps carrying a few stone tools as
> well - my goodness, they had their hands full ;-)
>
Yep. Certainly doesnt leave much room for quadrupedal locomotion
now does it! ;-)
> >. . . . . even ill educated termites can bring down tall buildings if
> >they are diligent enough in their gnawing! Not of course that I
> >would say AAH is exactly a "tall building"! Sorta low lying and
> >short of structural support. . . . . . ;-)
>
> Another great image! Gnaw away, termite :-)
And downright tasty with a little tabasco! ;-)))
Regards
bk
(Tabasco sauce even made C-Rations palatable! If of course you liked
tabasco sauce in LARGE quantities! ;-) )
Pauline M Ross
wrote:
>So you say rather conclusively that "water can get an ape walking
>bipedally". Does that mean that an ape can not and will not
>wade other than bipedally? Most apes are sometimes bipedal
>sometimes quadrupedal, both on land and in the water, would
>you not agree? Most apes are not "aquatic", at least not if that
>is one of the "separators" between us and the rest of them, right?
>If a non-aquatic still wades (bipedally or quadrupedally) how do
>we define "aquatic"?
Bob, you like to play with words, can you try to remember the words
'more' and 'less'? No one here is talking about 'aquatic' hominids,
but only about 'more aquatic' than modern apes.
>Is there a semi-aquatic, less than 1500 lbs, that does not have DENSE
>fur?
Yes, the pigmy hippo, 395-605 lbs. It's more complicated than than
just size!
>Woops! Are you REALLY saying that fur seals spend most of their time out
>of the water?
Yes, most seals spend most of their time hauled out.
>> [Pauline]Actually, I can't think of any
>> species with permanent fat which is *not* aquatic.
>
>Would you add "fully aquatic", or "completely aquatic"?
>One real example, albeit not "permanent" would be the Kodiak brown
>bears that put on a huge layer of fat snacking on the salmon runs,
There are lots of examples of terrestrial mammals which put on
seasonal fat. I don't see much evidence that humans do (or did) that,
do you?
>
>>[Pauline] I'm not trying to say that we *must* have been 'aquatic' because we
>> have no fur or subcutaneous fat or whatever; only that these things
>> *may* be connected with water and therefore that that should be
>> considered as one of options.
>
>Pauline, being considered is one thing, being accepted and embraced
>is another entirely! You consider them. Do you honestly think that our
>current nearly hairless condition was driven by a need to cut aquatic
>friction? Do you honestly believe that SC fat in humans was driven by
>a need for floation and aquatic insulation rather than as a store of
>high quality nutrition for the early infant development? If so, say
>so. If not, dont waffle around trying to protect AAH arguements. Its
>very unbecoming.
All I'm trying to do is be precise in what I say. I am *not* saying
"We were aquatic because we have X and Y...", because I don't think we
have enough evidence to say that definitively.
My views are exactly as I spelled out to you in my long post a while
back: that currently the possible reasons why humans are thought have
feature X are A, B, C, D,... and in my considered opinion one of them
is more plausible than the others.
When you repeat the exercise for a number of features, and the most
plausible reason for each is some degree of aquaticism, then some kind
of 'aquatic' history become inescapable.
I honestly don't care whether you or anyone else agrees with this, and
I have never disputed that there are difficulties with an 'aquatic'
model, but, to repeat, in my view the aquatic reasons for
hairlessness, subcutaneous fat, bipedalism, etc are *more plausible*
than anything else currently proposed and are therefore worthy of
consideration, along with terrestrial models.
--
Pauline Ross
Algis Kuliukas
> "Algis Kuliukas" <al...@RiverApes.com> wrote in message
> news:77a70442.0405...@posting.google.com...
>
> Snip. . .
> > > > In my opinion there was no single distinct 'aquatic phase' as such.
> > > > This is the one part of the original Hardy/Morgan hypothesis (ie a
> > > > post Pan-Homo LCA, pre Homo real aquatic phase) that Langdon did do a
> > > > good job of refuting - if only to point out that a'piths are hardly
> > > > indicative of being more aquatic than humans are which they should
> > > > have been if a real phase had happenned around 6mya.
>
> > > So would you say that whatever "aquatic adapations" that are present
> > > were done by the time of the apiths? If so, you have a bit of a
> problem I
> > > think.
> >
> > I think you must have misread what I wrote, Bob. If you read the above
> > para and the rest below you'll see that I don't think anything of the
> > sort. If anything more aquatic pressre happenned after the A'piths in
> > my opinion.
>
> Hey, this is good! we now have at least one "limit" in there for your
> particular concept of the AA! If most of the "aquatic pressures" were
> after the time of the apith, that would mean that bipedalism would
> necessarily be "off the table" as a characteristic primarily driven by
> aquatic factors, wouldnt it?
Trying to have a discussion with you is like trying to pin down a wet
piece of soap. First you completely misunderstand my point (I won't
say deliberately), then you twist my attempted clarification to better
your argument. Have you been taking lessons off Jim Moore?
I said 'if anything *more* aquatic pressure happenned after the
a'piths', not that *all* the pressure happenned after them.
Bipedalism before and, probably, swimming and diving later.
Algis Kuliukas
Jim McGinn
> 4) Penguins walk on land vertically like humans (straight bodies).
Penguins are birds, you idiot, so this is a lousy example of how
aquaticism cause bipedalism.
> > I date the end of the 'aquatic period' to the start of agriculturalism
> (say 10 kya).
>
> Yes. And even then: rice grows in shallow water.
You've outdone yourself with this piece of nonsense.
Bob Keeter
> On Mon, 10 May 2004 00:17:43 GMT, "Bob Keeter" <rke...@earthlink.net>
> wrote:
>
> >So you say rather conclusively that "water can get an ape walking
> >bipedally". Does that mean that an ape can not and will not
> >wade other than bipedally? Most apes are sometimes bipedal
> >sometimes quadrupedal, both on land and in the water, would
> >you not agree? Most apes are not "aquatic", at least not if that
> >is one of the "separators" between us and the rest of them, right?
> >If a non-aquatic still wades (bipedally or quadrupedally) how do
> >we define "aquatic"?
>
> Bob, you like to play with words, can you try to remember the words
> 'more' and 'less'? No one here is talking about 'aquatic' hominids,
> but only about 'more aquatic' than modern apes.
>
Words are the stock and trade of a discussion group. I tried pictures
to overcome a logjam over the meaning of words and you got after
me for that. Now I revert to words, and you take me to task again.
Im running out of options for communications. Do you know International
Morse Code by any chance? 8-) Seriously, Im begining to wonder if the
medium is simply a distraction and its the message that you have to attack
by virtue of the phrasing, terminology, or even medium used.
If that is happening, its really not a very scientifically oriented
approach.
I understand fully that the "aquatic ape, ala verhaugen, porpoising through
the waves" is not quite the piece of cake for thinking people, and, even
though I dont agree with your ideas, I have no trouble including you and
Algis and thinking people. If I didnt fully embrace that concept would I
waste my time with these discussions or just add you both to the noise
filter? I think that there is perhaps something to be gained in both
directions, and the only medium that seems to work at all is words.
Sorry of those words offended, but then again, I would offer the
initial train of reason and inference for your critique. Show me
where the "If A, then B" falls apart?
> >Is there a semi-aquatic, less than 1500 lbs, that does not have DENSE
> >fur?
>
> Yes, the pigmy hippo, 395-605 lbs. It's more complicated than than
> just size!
Hate to say that I smelt that one coming, but if you have ever stood
by the hippo pool at a zoo, you know what I mean. The pigmy hippo
does fill that "one order of magnitude" case, not by a lot (cant say that
ANYONE would ever mistake a 500 lb hippo for a 65 lb apith, but. . . .
I sat the limit, I take the hit! 8-(
However, I would have to question the circumstances for the pigmy hippo.
Is that the ancestoral form, a co-equal form, or a degenerative form (like
the pigmy mammoths that can be found where they developed from the
"full sized" versions under some very special conditions.) Still, a "hit"
is a
"hit" and I am forced to accept the fact that there exists (in the
mathematical
sense) an example of a <1500lb, relatively naked semi-aquatic mammal.
Ah well. loosing one battle is not grounds for conceeding the war! ;-)
> >Woops! Are you REALLY saying that fur seals spend most of their time out
> >of the water?
>
> Yes, most seals spend most of their time hauled out.
>
Citation?
I would offer up:
http://www.pinnipeds.org/species/guadfur.htm
Referring to the Guadalupe Fur Seal. . .
"About 7-8 days after the birth of her pup the mother mates and then leaves
to feed at sea. This begins a cycle, lasting about 8-9 months, where she
will spend an average of 9-13 days at sea before returning to land to nurse
her pup for an average of 5-6 days."
http://www.amonline.net.au/factsheets/fur_seal.htm (australian fur seal)
"Australian Fur Seals come ashore each year and form breeding colonies. The
adult males come ashore first and establish territories. Females congregate
within these areas and are defended by the resident male often with
considerable aggression towards the females and other males. Females spend
most of the gestation period at sea, coming ashore just before the birth of
a single pup between October and December. "
http://brainmuseum.org/Specimens/pinnipedia/northfurseal/ (northern fur
seal)
"C. ursinus spends most of its life at sea, coming ashore primarily to
breed. This accounts for 60-70 days per year and occur on a few tiny islands
found within the vast oceanic range of the Northern Fur Seal."
At least for C. ursinus, this would mean at least 280 or more days per year
at sea.
> >> [Pauline]Actually, I can't think of any
> >> species with permanent fat which is *not* aquatic.
> >
> >Would you add "fully aquatic", or "completely aquatic"?
> >One real example, albeit not "permanent" would be the Kodiak brown
> >bears that put on a huge layer of fat snacking on the salmon runs,
>
> There are lots of examples of terrestrial mammals which put on
> seasonal fat. I don't see much evidence that humans do (or did) that,
> do you?
Not really, that was only an example of mammals, and specifically
one that does exploit aquatic resources for a very important part
of its life, that use fat as a nutritional storehouse. Thats all. The
fat does NOT have to be there for insulation or floatation EVEN
in an aquatic-connected / water-side creature.
> >
> >>[Pauline] I'm not trying to say that we *must* have been 'aquatic'
because we
> >> have no fur or subcutaneous fat or whatever; only that these things
> >> *may* be connected with water and therefore that that should be
> >> considered as one of options.
> >
> >Pauline, being considered is one thing, being accepted and embraced
> >is another entirely! You consider them. Do you honestly think that our
> >current nearly hairless condition was driven by a need to cut aquatic
> >friction? Do you honestly believe that SC fat in humans was driven by
> >a need for floation and aquatic insulation rather than as a store of
> >high quality nutrition for the early infant development? If so, say
> >so. If not, dont waffle around trying to protect AAH arguements. Its
> >very unbecoming.
>
> All I'm trying to do is be precise in what I say. I am *not* saying
> "We were aquatic because we have X and Y...", because I don't think we
> have enough evidence to say that definitively.
>
Good!
> My views are exactly as I spelled out to you in my long post a while
> back: that currently the possible reasons why humans are thought have
> feature X are A, B, C, D,... and in my considered opinion one of them
> is more plausible than the others.
And that opinion is subject to change based on other evidence and trains
of thought? Hopefully anyway?
> When you repeat the exercise for a number of features, and the most
> plausible reason for each is some degree of aquaticism, then some kind
> of 'aquatic' history become inescapable.
>
So long as that is your OPINION and you feel no compulsion to try to
peddle that as "obvious facts" and the underlying reason for the vast
anti-AAH conspiracy, have at it! Now if you feel the urge to call everyone
who happens to disagree with you an idiot, Id recommend about 20 deep
breaths into a grocery bag to get the blood chemistry back in business! ;-)
> I honestly don't care whether you or anyone else agrees with this, and
> I have never disputed that there are difficulties with an 'aquatic'
> model, but, to repeat, in my view the aquatic reasons for
> hairlessness, subcutaneous fat, bipedalism, etc are *more plausible*
> than anything else currently proposed and are therefore worthy of
> consideration, along with terrestrial models.
No problem. Worthy of consideration means that EVERYONE gets
to pick and choose, and even to disagree, right? 8-) It even means
that I still have the right (and privelege) to try to find that one
arguement
or one piece of evidence or one set of circumstances that would make
you (and algis!) slap your foreheads and expound something along the
lines of "Geez, how could I not have seen this. . . . ." ;-))
Regards
bk
Bob Keeter
"Algis Kuliukas" <al...@RiverApes.com> wrote in message
news:77a70442.0405...@posting.google.com...
Snippage. . . . . .
> > > I think you must have misread what I wrote, Bob. If you read the above
> > > para and the rest below you'll see that I don't think anything of the
> > > sort. If anything more aquatic pressre happenned after the A'piths in
> > > my opinion.
> >
> > Hey, this is good! we now have at least one "limit" in there for your
> > particular concept of the AA! If most of the "aquatic pressures" were
> > after the time of the apith, that would mean that bipedalism would
> > necessarily be "off the table" as a characteristic primarily driven by
> > aquatic factors, wouldnt it?
>
> Trying to have a discussion with you is like trying to pin down a wet
> piece of soap. First you completely misunderstand my point (I won't
> say deliberately), then you twist my attempted clarification to better
> your argument. Have you been taking lessons off Jim Moore?
>
I will freely admit to playing just a bit with your responses. My
apologies for not including enough smiley faces to betray my fun.
> I said 'if anything *more* aquatic pressure happenned after the
> a'piths', not that *all* the pressure happenned after them.
> Bipedalism before and, probably, swimming and diving later.
>
At risk of being taken wrongly, if swimming was an adaptive trait
that occured AFTER the apiths, that would seem to suggest that
it also occured after the Pan/Homo divergence, right? That would
mean that chimps should not be able to swim, right? How do you
handle the example of the reluctant but swimming chimp that has
been cited several times here?
Regards
bk
Marc Verhaegen
"Bob Keeter" <rke...@earthlink.net> wrote an incredible example of
black-white thinking in message
news:fGVnc.5483$KE6....@newsread3.news.atl.earthlink.net...
Pauline M Ross
wrote:
>>[Pauline] Bob, you like to play with words, can you try to remember the words
>> 'more' and 'less'? No one here is talking about 'aquatic' hominids,
>> but only about 'more aquatic' than modern apes.
>>
>Words are the stock and trade of a discussion group. I tried pictures
>to overcome a logjam over the meaning of words and you got after
>me for that. Now I revert to words, and you take me to task again.
>Im running out of options for communications. Do you know International
>Morse Code by any chance? 8-)
Sorry! No really, I didn't mean to sound quite so tetchy :-( I did
(and do) object to the idea of trying to attach images of modern
landscapes to Apith habitat because a) the landscape is likely to have
changed quite a bit in 3 My, and b) the 'Apith habitat' was actually a
range of different habitats. One Apith fossil might have been in
closed woodland with edaphic grasses, another in open
woodland/bushland with a river, and so on. Trying to summarise all
that in an image (or even a series of images) is bound to be
misleading, I think. We all know what Reed means by 'closed woodland'
or 'bushland' or 'gallery forest', so let's leave it at that.
As to the words, you're right, we can't do without them here, so let
me have another go at the questions you asked:
>> >So you say rather conclusively that "water can get an ape walking
>> >bipedally". Does that mean that an ape can not and will not
>> >wade other than bipedally?
Modern apes have been observed wading bipedally and quadrupedally. I
suppose it depends on how deep the water is - in shallow water, they
could do either, in deeper water they have to wade bipedally (or swim,
but we know how unusual that is!).
>>> Most apes are sometimes bipedal
>> >sometimes quadrupedal, both on land and in the water, would
>> >you not agree?
Yes. On land they mostly move quadrupedally, but they may stand or
(occasionally) move bipedally. In water, they mostly move bipedally
(but they don't often go into water).
>>> Most apes are not "aquatic", at least not if that
>> >is one of the "separators" between us and the rest of them, right?
>> >If a non-aquatic still wades (bipedally or quadrupedally) how do
>> >we define "aquatic"?
It's not an either/or thing, Bob. You can't divide the world into
aquatic and non-aquatic (well, you could, but it isn't very
meaningful). There is a spectrum - from totally non-aquatic at one end
(never goes into water) to totally aquatic at the other (never leaves
the water), but most mammals fall somewhere in between. Modern chimps
are towards the non-aquatic end, modern humans further towards the
aquatic end. So the issue is 'more aquatic', not 'aquatic'.
>> >[Bob]Woops! Are you REALLY saying that fur seals spend most of their time out
>> >of the water?
>>
>>[Pauline] Yes, most seals spend most of their time hauled out.
>>
>Citation? I would offer up:
[Snip several quotes showing that fur seals spend most of their time
at sea]
OK, OK, I'll give you the fur seals :-) I can't even justify my
'most' without trawling through umpteen different seal species, which
I can't be bothered doing right now! Let me rephrase: all seals spend
a sizeable proportion of their time ashore, some spend most of their
time ashore. Better? The point remains: the fur is useful when they
are on land, and is therefore retained.
>[the Kodiak bear] was only an example of mammals, and specifically
>one that does exploit aquatic resources for a very important part
>of its life, that use fat as a nutritional storehouse. Thats all. The
>fat does NOT have to be there for insulation or floatation EVEN
>in an aquatic-connected / water-side creature.
Agreed. In terrestrial (or largely terrestrial) the usual reason for
fat is a seasonal accumulation as an energy store. But I repeat, I
don't see any sign of seasonal energy needs in humans.
>> [Pauline] My views are exactly as I spelled out to you in my long post a while
>> back: that currently the possible reasons why humans are thought have
>> feature X are A, B, C, D,... and in my considered opinion one of them
>> is more plausible than the others.
>
>And that opinion is subject to change based on other evidence and trains
>of thought? Hopefully anyway?
Absolutely. That is why I'm here, in fact. It niggles at the back of
my mind that so many professional PAs dismiss the AAH, I keep thinking
that they can't all be wrong, surely. There must be something I'm
missing. But in several years of hanging around here, I haven't yet
seen the killer piece of evidence.
But if you want to convince me, the best way is to provide more
plausible explanations for human bipedalism, hairlessness,
subcutaneous fat and all the other paraphernalia. Wheeling out fur
seals, giant otters or Kodiak bears isn't going to do it, nor is
agonising over the meaning of 'aquatic'. I already know that there are
difficulties with the aquatic model, but nevertheless it is still (in
my opinion) more plausible than any of the alternatives.
So go to it, termite - convince me that you have a more plausible
explanation for (say) hairlessness :-)
--
Pauline Ross
Jim McGinn
> I already know that there are
> difficulties with the aquatic model,
Statements like this always crack me up. Pauline, you
haven't presented a model of any sort whatsoever. You've
done nothing but make vague allusions to the supposition
that hominids lived close to water. How is this,
supposedly, a model?
> but nevertheless it is still (in
> my opinion) more plausible than any of the alternatives.
You're living in a complete dreamworld.
Jim
Bob Keeter
Snip
> >Words are the stock and trade of a discussion group. I tried pictures
> >to overcome a logjam over the meaning of words and you got after
> >me for that. Now I revert to words, and you take me to task again.
> >Im running out of options for communications. Do you know International
> >Morse Code by any chance? 8-)
>
> Sorry! No really, I didn't mean to sound quite so tetchy :-(
Not a problem.
> I did
> (and do) object to the idea of trying to attach images of modern
> landscapes to Apith habitat because a) the landscape is likely to have
> changed quite a bit in 3 My, and b) the 'Apith habitat' was actually a
> range of different habitats. One Apith fossil might have been in
> closed woodland with edaphic grasses, another in open
> woodland/bushland with a river, and so on. Trying to summarise all
> that in an image (or even a series of images) is bound to be
> misleading, I think. We all know what Reed means by 'closed woodland'
> or 'bushland' or 'gallery forest', so let's leave it at that.
What DID she mean. The only real definition that I saw that
described her meaning was the pictures, not of the Apith sites,
but of modern sites that she used as the basis of her analysis. Her
concept was that by matching the bone assembleages in relative
proportions of species, that she could tie the modern observable
habitat to the ancient, unobservable habitat. Try as I may, I dont
think that I can really do much better than her statistical analysis,
although I would have used different techniques. So, Im forced
to believe that when she matches two assembleges of "open woodland"
bone sets, there is a high likelyhood (given the correlations provided)
that those two bone sets came from "open woodland" whether ancient
or modern. Then I look at a picture of the sites she used for the
"modern equivalents" and I think, when I hear words "open woodland",
REGARDLESS of the period, it means this picture or something very
similar. It does not involve twisting around meanings of words
or playing any kind of "lets pretend". I see a picture with the "label"
open woodland in the authors paper, and I believe that this is
what SHE believes open woodland to look like.
Is this wrong? Do you know better what the author's idea of
open woodland is than she does? Im sorry, but thats starting
to get a bit over the edge dont you think?
> As to the words, you're right, we can't do without them here, so let
> me have another go at the questions you asked:
Also take a go at the one above. The pictures of the places that the
author apparently thinks to be "open woodland" or for that matter the
other ecologies, dont agree with your interpretations of the words
in the article. (or at least they are "difficult" enough that you would
prefer some other pictures). Who should we (or you) believe, the
possibly mis-construed meanings of the words and sentences, or
the author's flat statement that the "benchmark" for a "closed
woodland" is W. Lunga National Park in Zambia or an "open
woodland" is the Sudan Savanna, in Nigeria?
That, Paulene is one of those questions that YOU have to answer
for YOURSELF, I really dont need to see it in print, although I
dont think it will be hard to discern in the response.
> >> >So you say rather conclusively that "water can get an ape walking
> >> >bipedally". Does that mean that an ape can not and will not
> >> >wade other than bipedally?
>
> Modern apes have been observed wading bipedally and quadrupedally. I
> suppose it depends on how deep the water is - in shallow water, they
> could do either, in deeper water they have to wade bipedally (or swim,
> but we know how unusual that is!).
8-) Unusual is a good term!
http://village.infoweb.ne.jp/~yukimaki/snow_monkey.jpg
http://www.africatours.ch/uganda/kl_chimp_in_water_ngamba.jpg
http://arts.anu.edu.au/grovco/pics/gorilla%20in%20water.jpg
> >>> Most apes are sometimes bipedal
> >> >sometimes quadrupedal, both on land and in the water, would
> >> >you not agree?
>
> Yes. On land they mostly move quadrupedally, but they may stand or
> (occasionally) move bipedally. In water, they mostly move bipedally
> (but they don't often go into water).
But its only in the deep water where there would be any "need" to go
bipedally? Hmmmm. . . .
> >>> Most apes are not "aquatic", at least not if that
> >> >is one of the "separators" between us and the rest of them, right?
> >> >If a non-aquatic still wades (bipedally or quadrupedally) how do
> >> >we define "aquatic"?
>
> It's not an either/or thing, Bob. You can't divide the world into
> aquatic and non-aquatic (well, you could, but it isn't very
> meaningful). There is a spectrum - from totally non-aquatic at one end
> (never goes into water) to totally aquatic at the other (never leaves
> the water), but most mammals fall somewhere in between. Modern chimps
> are towards the non-aquatic end, modern humans further towards the
> aquatic end. So the issue is 'more aquatic', not 'aquatic'.
>
> >> >[Bob]Woops! Are you REALLY saying that fur seals spend most of their
time out
> >> >of the water?
> >>
> >>[Pauline] Yes, most seals spend most of their time hauled out.
> >>
> >Citation? I would offer up:
> [Snip several quotes showing that fur seals spend most of their time
> at sea]
>
> OK, OK, I'll give you the fur seals :-) I can't even justify my
> 'most' without trawling through umpteen different seal species, which
> I can't be bothered doing right now! Let me rephrase: all seals spend
> a sizeable proportion of their time ashore, some spend most of their
> time ashore. Better? The point remains: the fur is useful when they
> are on land, and is therefore retained.
Yep. Totally OK. Outstanding in fact, since it sets up the
next question.
. . . . . . . . . . . . Is your concept of an aquatic ape IN the water
so much that a pelt would be a disadvantage from an evolutionary
standpoint and therefore be "lost" through the process of natural
selection? Just remember, we already know from hard examples
that 70 days out of 360 days of existence on the land (even if
in VERY close proximity to the water), is enough of an exposure
to the terrestrial environment to retain fur OR that 290 days of
swimming free in the ocean (home of orcas, great whites and even
leopard seals), is not enough of an aquatic exposure to FORCE
the loss of hair! 8-)
Do you really, honestly think, from a scientific perspective, that
hairlessness in humans can be assumed to bear any significance
with respect to a hypothetical aquatic past for hominids?
> >[the Kodiak bear] was only an example of mammals, and specifically
> >one that does exploit aquatic resources for a very important part
> >of its life, that use fat as a nutritional storehouse. Thats all. The
> >fat does NOT have to be there for insulation or floatation EVEN
> >in an aquatic-connected / water-side creature.
>
> Agreed. In terrestrial (or largely terrestrial) the usual reason for
> fat is a seasonal accumulation as an energy store. But I repeat, I
> don't see any sign of seasonal energy needs in humans.
Nope. Not saying that its seasonal at all (although I think that some
women, particularly who live H/G lifestyles in some very unforgiving
regions (for example the San) who have a condition called steatopygia.
http://www.andaman.org/book/chapter5/text5.htm
Might even be interesting that some of the very earliest female figurines
seem to show proportions very much like the modern humans with
steatopygia. Could it be that humans (along with many mammalian
inhabitants of hostile environments) have an inate capability to "pack
on the fat" when the eating is good to tide one over when things get
hard? I daresay that the environment of post-glacial Europe might
have been very trying, particularly on human females who might have
had to support two appetites. Could it be that the "Venuses" represent
females that were able to actually support nursing children through the
"hard times" and therefore revered in stone? Hmmmm. . . lots of
side questions there I think! Our real question is the purpose of
body fat in humans. . . . isnt it! 8-)
> >> [Pauline] My views are exactly as I spelled out to you in my long post
a while
> >> back: that currently the possible reasons why humans are thought have
> >> feature X are A, B, C, D,... and in my considered opinion one of them
> >> is more plausible than the others.
> >
> >And that opinion is subject to change based on other evidence and trains
> >of thought? Hopefully anyway?
>
> Absolutely. That is why I'm here, in fact. It niggles at the back of
> my mind that so many professional PAs dismiss the AAH, I keep thinking
> that they can't all be wrong, surely. There must be something I'm
> missing. But in several years of hanging around here, I haven't yet
> seen the killer piece of evidence.
I doubt that you will find that "killer", but that does not stop me, a
flagrant amateur from looking for it either! 8-)
> But if you want to convince me, the best way is to provide more
> plausible explanations for human bipedalism, hairlessness,
> subcutaneous fat and all the other paraphernalia. Wheeling out fur
> seals, giant otters or Kodiak bears isn't going to do it, nor is
> agonising over the meaning of 'aquatic'. I already know that there are
> difficulties with the aquatic model, but nevertheless it is still (in
> my opinion) more plausible than any of the alternatives.
ANd it may always stay that way. And you may not even be able
to justify it to yourself, but you may continue to believe whatever
you want. 8-) Otherwise there might be some real problems in
all of the worlds' great religions I think!
> So go to it, termite - convince me that you have a more plausible
> explanation for (say) hairlessness :-)
>
At least from the crunchy stuff twixt the teeth, I would say that perhaps
I offered one or two crumbly floor joists just above! 8-)
Regards
bk
Pauline M Ross
wrote:
>>[Pauline]We all know what Reed means by 'closed woodland'
>> or 'bushland' or 'gallery forest', so let's leave it at that.
>
>What DID she mean. The only real definition that I saw that
>described her meaning was the pictures, not of the Apith sites,
>but of modern sites that she used as the basis of her analysis.
Exactly. She defines 8 habitats (she describes them as examples) and
draws scale diagrams of them so that no one can be in any doubt as to
what she means.
[Snip]
> Then I look at a picture of the sites she used for the
>"modern equivalents" and I think, when I hear words "open woodland",
>REGARDLESS of the period, it means this picture or something very
>similar. It does not involve twisting around meanings of words
>or playing any kind of "lets pretend". I see a picture with the "label"
>open woodland in the authors paper, and I believe that this is
>what SHE believes open woodland to look like.
Of course it is. Who ever said any different? What are you accusing me
of? Where have I twisted her words or played 'let's pretend'? I have
always been happy to go along with what's in the paper (words *and*
pictures). I only object to trying to tie Reed's definitions/drawings
to photographs, which adds nothing and may not be as precise as what
is in the paper. We *know* what she means, because she tells us. What
more do you need?
[Snip]
>Also take a go at the one above. The pictures of the places that the
>author apparently thinks to be "open woodland" or for that matter the
>other ecologies, dont agree with your interpretations of the words
>in the article. (or at least they are "difficult" enough that you would
>prefer some other pictures).
What? Where did you get that idea from?
> Who should we (or you) believe, the
>possibly mis-construed meanings of the words and sentences, or
>the author's flat statement that the "benchmark" for a "closed
>woodland" is W. Lunga National Park in Zambia or an "open
>woodland" is the Sudan Savanna, in Nigeria?
Bob, she doesn't say that West Lunga is the 'benchmark' for anything.
It is one of the places mentioned in Figure 2, p 292, showing
percentages of arboreal locomotion (and she describes it as "closed
woodland/bushland"), and it gets another mention in Table 1, p 294, of
modern African habitat localities (described as "closed
woodland/bushland transition"). It's one of the places in her
analysis, that's all.
Look, I don't know what you think I have been saying, with regard to
these pictures of yours, but let me spell this out once and for all. I
do not have any problem with Reed's paper, or her descriptions of the
various habitats, or her placement of the various fossils in those
habitats. None whatsoever.
My only objection is to *you* trying to match those habitats to some
arbitrary collection of pictures from tourist websites, which (at
best) adds nothing to Reed's descriptions and (at worst) *may*
actually be misleading. If you want to do this for your own interest,
fine, but I am happy to stick with what's in the paper.
>. . . . . . . . . . . . Is your concept of an aquatic ape IN the water
>so much that a pelt would be a disadvantage from an evolutionary
>standpoint and therefore be "lost" through the process of natural
>selection? Just remember, we already know from hard examples
>that 70 days out of 360 days of existence on the land (even if
>in VERY close proximity to the water), is enough of an exposure
>to the terrestrial environment to retain fur OR that 290 days of
>swimming free in the ocean (home of orcas, great whites and even
>leopard seals), is not enough of an aquatic exposure to FORCE
>the loss of hair! 8-)
You are still working on the assumption that I think that aquaticism
and hairlessness are directly correlated. I don't. I think it possible
that hairlessness is related to aquaticism *and* body size *and* local
climate *and* lifestyle (and possibly other factors, who knows) by
some complicated formula that I can't guess at. But I do think that
hairlessness in humans is more likely to be due to one or more of
these known factors, rather than being a special one-off case that
only applies to us (like being part of a unique sweat-cooling
mechanism which no other species seems to have discovered the benefits
of).
>Nope. Not saying that [human fat is] seasonal at all (although I think that some
>women, particularly who live H/G lifestyles in some very unforgiving
>regions (for example the San) who have a condition called steatopygia.
Yes, it's not hard to see that as a variation on standard female body
fat, which happens to have shifted to the buttocks to minimise the
inconvenience of fat in a hot climate. Which makes one wonder how we
could have acquired fat in a hot climate in the first place, doesn't
it?
> Our real question is the purpose of
>body fat in humans. . . . isnt it! 8-)
Indeed.
--
Pauline Ross
Marc Verhaegen
> > Our real question is the purpose of body fat in humans. . . . isnt it!
8-)
> Indeed. -- Pauline Ross
We must discern between questions of (1) comparative anatomy & of (2)
functional purpose.
(2) SC fat can have a lot of possible functions (energy depot, thermic
insulation in water, on land, mechanical insulation in water, on land,
estrogen depot, hindrance to diving, shaping body contours, influncing
equilibrium (eg, in bipeds), etc.), it's difficult to know which of these
possible functions must have played a role in human evolution. Moreover,
functions change during evolution.
(1) What we do know is that medium-sized mammals with a lot of fat
frequently if not always spend a lot of time in water. Why would this be
different for humans or their ancestors?? IOW, if somebody claims that human
ancestors were not waterside sometime after the Homo/Pan split, he has to
give good arguments. So, I haven't seen any.
Jim McGinn
> My only objection is to *you* trying to match those habitats to some
> arbitrary collection of pictures from tourist websites, which (at
> best) adds nothing to Reed's descriptions and (at worst) *may*
> actually be misleading. If you want to do this for your own interest,
> fine, but I am happy to stick with what's in the paper.
Science never suffers from being too explicit, Pauline.
We all know the real source of your objection to the
pictures from the tourist website. They didn't confirm
the details of your aquatic fantasies. One wonders why
you even bother to pretend to be objective.
Jim
Paul Crowley
news:40a2011c$0$9757$a0ce...@news.skynet.be...
> > > Our real question is the purpose of body fat in humans. . . . isnt it!
> We must discern between questions of (1) comparative anatomy & of (2)
> functional purpose.
>
> (2) SC fat can have a lot of possible functions (energy depot, thermic
> insulation in water, on land, mechanical insulation in water, on land,
> estrogen depot, hindrance to diving, shaping body contours, influncing
> equilibrium (eg, in bipeds), etc.), it's difficult to know which of these
> possible functions must have played a role in human evolution. Moreover,
> functions change during evolution.
Changes of function during evolution are
vanishingly rare -- especially when a taxon
adopts an extremely unusual feature (such
as a high degree of fat in a medium-sized
terrestrial animal).
> (1) What we do know is that medium-sized mammals with a lot of fat
> frequently if not always spend a lot of time in water. Why would this be
> different for humans or their ancestors??
Err . . . (a) because they needed the fat for one
of the OTHER 'lot of possible functions' you
list above . . . OR for one that you have
overlooked. . . ?
(b) because the current population of hominids
spends almost no time immersed in water . .?
(c) because no good reason can be specified
why the ancestors of the current population
would have spent any amount of time in water
at any time within the past few hundred (or even
few million) years . . ?
(d) because fat is an exceedingly expensive
feature . . . which would have been discarded
the instant the current species (or any of its
populations) ceased to have an imperative
need for it . . .?
> IOW, if somebody claims that human
> ancestors were not waterside
'Waterside' is a ridiculous description -- chosen
only because it is confusing and misleading.
The issue here is whether or not recent human
ancestors (within the last few Kyr) spent a lot
of time _immersed_ in water.
Clearly they did not.
Paul.
Marc Verhaegen
"Paul Crowley" <slkwuoiut...@slkjlskjoioue.com> wrote in message
news:zswoc.7569$qP2....@news.indigo.ie...
> Changes of function during evolution are vanishingly rare
Are extremely frequent, you mean. Upper limbs to fly (birds), to swim
(whales), to run (dogs), to grasp (primates)...
Jim McGinn
> Look, I don't know what you think I have been saying, with regard to
> these pictures of yours, but let me spell this out once and for all. I
> do not have any problem with Reed's paper, or her descriptions of the
> various habitats, or her placement of the various fossils in those
> habitats. None whatsoever.
>
> My only objection is to *you* trying to match those habitats to some
> arbitrary collection of pictures from tourist websites, which (at
> best) adds nothing to Reed's descriptions and (at worst) *may*
> actually be misleading. If you want to do this for your own interest,
> fine, but I am happy to stick with what's in the paper.
Why don't you stop whining and tell us what,
exactly, it is about the details of these
pictures that you find so troubling? It seems
to me that Bob is just trying to paint a fuller
picture of the habitat. It seems obvious to me
that your objections have more to do with the
fact that there's not as much water in those
pictures as there is in the pictures in your
head.
Dream on, Pauline.
Jim
Bob Keeter
Snip
> >What DID she mean. The only real definition that I saw that
> >described her meaning was the pictures, not of the Apith sites,
> >but of modern sites that she used as the basis of her analysis.
>
> Exactly. She defines 8 habitats (she describes them as examples) and
> draws scale diagrams of them so that no one can be in any doubt as to
> what she means.
Snip.
> > Then I look at a picture of the sites she used for the
> >"modern equivalents" and I think, when I hear words "open woodland",
> >REGARDLESS of the period, it means this picture or something very
> >similar. It does not involve twisting around meanings of words
> >or playing any kind of "lets pretend". I see a picture with the "label"
> >open woodland in the authors paper, and I believe that this is
> >what SHE believes open woodland to look like.
>
> Of course it is. Who ever said any different? What are you accusing me
> of? Where have I twisted her words or played 'let's pretend'? I have
> always been happy to go along with what's in the paper (words *and*
> pictures). I only object to trying to tie Reed's definitions/drawings
> to photographs, which adds nothing and may not be as precise as what
> is in the paper. We *know* what she means, because she tells us. What
> more do you need?
Well, I think that perhaps there may be some accusations in there
somewhere, and perhaps not all mine! 8-)
However, an idea just occurs to me. I pulled the pictures I offered right
off the top of the pile that Google offered up. I would ask, as a favor,
and
perhaps to prevent this arguement turning into something ugly and
unnecessary,
that YOU provide some web references to pictures of the appropriate
locations
that show what you think some of those "controversial" environments really
do (and would have) looked like. Not the sketches (still dont know why
those were even included!), but rather the true pictures of the locales that
were used as the standards against which the fossil data could be compared.
Take "open woodland", "open woodland/brushland" and maybe "brushland",
and you can show me a picture of what those look like (using the authors
table to tie the words to the locations of course). I dont care who took
the
pictures, just so long as a reasonable person would be able to assume
that those pictures came from the areas mentioned. Pictures are pictures,
and even in this day of photo-altering software, I dont think that anyone
would take the time to do a good job on a picture of trees, hills and
plains!
;-)
You see, Im willing to let you define the words, so long as we both know
EXACTLY the picture that the words apply to. Im sort of paleolythic
I think. Rock paintings are SO much easier to understand than written
words! 8-)
> [Snip]
> >Also take a go at the one above. The pictures of the places that the
> >author apparently thinks to be "open woodland" or for that matter the
> >other ecologies, dont agree with your interpretations of the words
> >in the article. (or at least they are "difficult" enough that you would
> >prefer some other pictures).
>
> What? Where did you get that idea from?
You did get rather upset with me over the pictures that I turned up. . . . .
There must have been a reason.
> > Who should we (or you) believe, the
> >possibly mis-construed meanings of the words and sentences, or
> >the author's flat statement that the "benchmark" for a "closed
> >woodland" is W. Lunga National Park in Zambia or an "open
> >woodland" is the Sudan Savanna, in Nigeria?
>
> Bob, she doesn't say that West Lunga is the 'benchmark' for anything.
> It is one of the places mentioned in Figure 2, p 292, showing
> percentages of arboreal locomotion (and she describes it as "closed
> woodland/bushland"), and it gets another mention in Table 1, p 294, of
> modern African habitat localities (described as "closed
> woodland/bushland transition"). It's one of the places in her
> analysis, that's all.
Thats exactly and precisely right! West Lunga is a woodland/brushland,
and an example of a woodland/brushland, by her definition, is W. Lunga!
I have no problem with her definition, whatsoever. I just want to be able
to accurately visualize what a "woodland brushland" looks like. How far
between trees, how much grass, how much brush, maybe even how much
open water! A picture does a lot of that.
> Look, I don't know what you think I have been saying, with regard to
> these pictures of yours, but let me spell this out once and for all. I
> do not have any problem with Reed's paper, or her descriptions of the
> various habitats, or her placement of the various fossils in those
> habitats. None whatsoever.
>
OK. Well, Can you supply the pictures! I will accept your pictures
of W. Lunga and the others without question! Just show me what an
"Open Forest/Brushland transition" looks like, based on the author's
contention that said environment can be found in W. Lunga! Maybe even
do the same for a couple of others, so that I have no doubt what you
and the author is really meaning by that term! Right now, for all I know,
we are either diametrically opposite on our personal meanings of those
words, or in violent agreement! Show me the picture!
> My only objection is to *you* trying to match those habitats to some
> arbitrary collection of pictures from tourist websites, which (at
> best) adds nothing to Reed's descriptions and (at worst) *may*
> actually be misleading. If you want to do this for your own interest,
> fine, but I am happy to stick with what's in the paper.
>
Then mislead me. SHOW me the pictures!
> >. . . . . . . . . . . . Is your concept of an aquatic ape IN the water
> >so much that a pelt would be a disadvantage from an evolutionary
> >standpoint and therefore be "lost" through the process of natural
> >selection? Just remember, we already know from hard examples
> >that 70 days out of 360 days of existence on the land (even if
> >in VERY close proximity to the water), is enough of an exposure
> >to the terrestrial environment to retain fur OR that 290 days of
> >swimming free in the ocean (home of orcas, great whites and even
> >leopard seals), is not enough of an aquatic exposure to FORCE
> >the loss of hair! 8-)
>
> You are still working on the assumption that I think that aquaticism
> and hairlessness are directly correlated. I don't. I think it possible
> that hairlessness is related to aquaticism *and* body size *and* local
> climate *and* lifestyle (and possibly other factors, who knows) by
> some complicated formula that I can't guess at. But I do think that
> hairlessness in humans is more likely to be due to one or more of
> these known factors, rather than being a special one-off case that
> only applies to us (like being part of a unique sweat-cooling
> mechanism which no other species seems to have discovered the benefits
> of).
Er. . . . Why should hairlessness in humans be considered to be in the least
related to an aquatic connection, when even the very close, very intimate
and very compelling "association" between fur seals and the sea has not
forced hairlessness? I would toss in the example of the giant river otter,
the
Harbor Seal (found in permanent residence as far south as northern Mexico),
the Mediterranean and Hawaiian monk seals, and if I go to:
It would appear that there are some of those furry aquatic critters just
about
anywhere in the world, at just about all latitudes! Hmmmmmm.
> >Nope. Not saying that [human fat is] seasonal at all (although I think
that some
> >women, particularly who live H/G lifestyles in some very unforgiving
> >regions (for example the San) who have a condition called steatopygia.
>
> Yes, it's not hard to see that as a variation on standard female body
> fat, which happens to have shifted to the buttocks to minimise the
> inconvenience of fat in a hot climate. Which makes one wonder how we
> could have acquired fat in a hot climate in the first place, doesn't
> it?
AND how the most obvious "fat deposits" (steatopygia), seem to be most
obvious in that same climate. SERIOUSLY dont think that steatopygia is
any possible adaptation to an aquatic environment.
> > Our real question is the purpose of body fat in humans. . . . isnt it!
8-)
>
> Indeed.
So, we have multiple examples of completely, or primarily aquatic creatures
with significant fat deposits for insulation/floatation and we have at least
one
example of a hominid with fat accumulations totally impossible to explain by
too many trips to McDonalds for a "supersize". Do we use the cetacean model
to explain human body fat or do we use the human example, at least in
terms of hypothesizing the purpose, i.e food cacheing or floatation? Which
do YOU think is the best comparison to make?
Regards
bk
Paul Crowley
>
> "Paul Crowley" <slkwuoiut...@slkjlskjoioue.com> wrote in message
> news:zswoc.7569$qP2....@news.indigo.ie...
>
> > Changes of function during evolution are vanishingly rare
>
> Are extremely frequent, you mean.
Nope, vanishingly rare -- we see them when
a great family or class evolves into a wholly
new element -- and then they mostly apply to
standard features, like limbs
> Upper limbs to fly (birds),
Sure, and how often do we get the evolution
of a taxa the sixe of birds?
> to swim (whales),
How often do we get the evolution of a taxa the
sixe of cetacea?
> to run (dogs),
How often do we get the evolution of a taxa the
sixe of terrestrial mammals?
> to grasp (primates)...
How often do we get the evolution of a taxa the
sixe of primates?
You've made my point. When you have to
go to evolutionary steps of this magnitude
to find a comparison which (you claim) might
support some minor aspect of a theory about
the evolution of HUMAN BODY FAT, then
you've lost the argument.
Of course, you lost it anyway when you
'forgot' to deal with the rest of my post.
Paul.
Pauline M Ross
wrote:
>However, an idea just occurs to me. I pulled the pictures I offered right
>off the top of the pile that Google offered up. I would ask, as a favor,
>and
>perhaps to prevent this arguement turning into something ugly and
>unnecessary,
>that YOU provide some web references to pictures of the appropriate
>locations
>that show what you think some of those "controversial" environments really
>do (and would have) looked like. Not the sketches (still dont know why
>those were even included!), but rather the true pictures of the locales that
>were used as the standards against which the fossil data could be compared.
Bob, you are completely missing the point. It's not about my pictures,
or your pictures, it's about *any* pictures. I object to the
*principle* of trying to match photographs of real places to Reed's
example habitats and then, by extension, to Apith habitat. Can you not
see how futile that is? Unless you have hopped in your time machine
with a camera and nipped back 3 My, the whole exercise is pointless.
And all the time we could be discussing Reed's actual paper.....
And what on earth is a controversial environment, anyway???
>
>You did get rather upset with me over the pictures that I turned up. . . . .
>There must have been a reason.
Actually, this line (and Jim's comments) give me a clue as to what is
going on here - you think I don't like your pictures because they
don't show much water :-) Actually, I have to confess, I haven't
looked at most of them (the links were broken, and I couldn't be
bothered making the effort to fix them all), but I don't particularly
care what they actually are. It's not relevant.
>Thats exactly and precisely right! West Lunga is a woodland/brushland,
>and an example of a woodland/brushland, by her definition, is W. Lunga!
>I have no problem with her definition, whatsoever. I just want to be able
>to accurately visualize what a "woodland brushland" looks like. How far
>between trees, how much grass, how much brush, maybe even how much
>open water! A picture does a lot of that.
And the sketches in the paper itself give you exactly that (except the
water, of course, which is shown by the proportion of aquatic
species). Do you really want to talk about the paper, Bob, or do you
find your pictures more interesting?
>Er. . . . Why should hairlessness in humans be considered to be in the least
>related to an aquatic connection, when even the very close, very intimate
>and very compelling "association" between fur seals and the sea has not
>forced hairlessness?
Because all the totally aquatic mammals are hairless, without
exception. So clearly there is a connection.
[Snip table of eared seal distribution]
>It would appear that there are some of those furry aquatic critters just
>about
>anywhere in the world, at just about all latitudes! Hmmmmmm.
Except warm waters like the West Indies, SE Asia, the Philippines,
etc. There are very few pinnipeds outside polar amd sub-polar regions.
>AND how the most obvious "fat deposits" (steatopygia), seem to be most
>obvious in that same climate. SERIOUSLY dont think that steatopygia is
>any possible adaptation to an aquatic environment.
No one proposes that it is. But *all* human females have a lot of fat,
the steatopygia is just an unusual way of positioning it, which is
generally believed to be a response to a continuing need for that fat
in a climate where carrying body fat is not normally advantageous. In
other words, human body fat (of any sort) is unlikely to have evolved
in a hot, dry climate.
>So, we have multiple examples of completely, or primarily aquatic creatures
>with significant fat deposits for insulation/floatation and we have at least
>one
>example of a hominid with fat accumulations totally impossible to explain by
>too many trips to McDonalds for a "supersize". Do we use the cetacean model
>to explain human body fat or do we use the human example, at least in
>terms of hypothesizing the purpose, i.e food cacheing or floatation? Which
>do YOU think is the best comparison to make?
Multiple examples versus one example? I'd start with the multiple
examples, wouldn't you?
Here's another way of looking at it: fat is used for insulation,
floatation and streamlining by aquatic mammals, and as a seasonal
energy store by terrestrial mammals. Modern humans are terrestrial, so
the energy store is where I'd look first. Only if that explanation is
unconvincing would I start looking for an aquatic explanation. But as
I've said before, the standard (energy-store) explanations are
deficient (in my opinion), so an aquatic explanation is worth 'keeping
on the table', so to speak.
--
Pauline Ross
firstjois
[snip]
>> No one proposes that it is. But *all* human females have a lot of
>> fat, the steatopygia is just an unusual way of positioning it, which
>> is generally believed to be a response to a continuing need for that
>> fat in a climate where carrying body fat is not normally
>> advantageous. In other words, human body fat (of any sort) is
>> unlikely to have evolved in a hot, dry climate.
>>
[snip]
>> Pauline Ross
Is that really true? I volunteer at a local elementary school and see a
lot of toothpicks between the ages of 5-10 years of age. Not *all* human
females have a lot of fat. We have dragged bedsprings all over this ground
before. Why do we have to do this over and over again? Is it sloppy
writing or do you actually not have children to look at where you live?
Is there any mammal incapable of storing extra food as fat?
Jois
Jim McGinn
> I object to the
> *principle* of trying to match photographs of real places to Reed's
> example habitats and then, by extension, to Apith habitat.
> Actually, this line (and Jim's comments) give me a clue as to what is
> going on here - you think I don't like your pictures because they
> don't show much water :-)
Pauline, your evasiveness is plainly obvious. It's as
obvious as Jim Moore's or Mikey Brass's evasiveness
when I asked them to explain their multi-niche nonsense
(Mosaic theory). Real scientists don't fear
explicitness, they embrace it.
> Actually, I have to confess, I haven't
> looked at most of them (the links were broken, and I couldn't be
> bothered making the effort to fix them all), but I don't particularly
> care what they actually are. It's not relevant.
It is relevant, and you know it. It just that these
details contrast the vague aquatic notions in your
head and you're doing your best to protect these
notions.
> Here's another way of looking at it: fat is used for insulation,
> floatation and streamlining by aquatic mammals, and as a seasonal
> energy store by terrestrial mammals. Modern humans are terrestrial, so
> the energy store is where I'd look first.
Uh, okay.
Only if that explanation is
> unconvincing would I start looking for an aquatic explanation. But as
> I've said before, the standard (energy-store) explanations are
> deficient (in my opinion),
Where's the evidentiary support for your opinion,
Pauline? Why is it that you aquatic whako's seem
to think that the rest of us are under some kind
of obligation to dispute your silly and vaguely
defined aquatic notions with evidence but you
yourself can dismiss the thinking of others based
on nothing but your opinion.
Jim
Marc Verhaegen
> ... steatopygia is just an unusual way of positioning it, which is
generally believed to be a response to a continuing need for that fat in a
climate where carrying body fat is not normally advantageous. In other
words, human body fat (of any sort) is unlikely to have evolved in a hot,
dry climate.
Localised fat depots are not unsual in camels, dromedaries, zebus,
fat-tailed lemurs, woolly mammoths... Must have something to do with
periodic shortness of food, eg, dry season? IIRC, in camels they vary from 0
to 8 % of body Wt. This fat is unlike the human SC fat (normally 15-20 % in
women).
--Marc
Mikey Brass
news:ac6a5059.04051...@posting.google.com:
> Pauline M Ross <pmr...@ross-software.co.uk> wrote
>
>> I object to the
>> *principle* of trying to match photographs of real places to Reed's
>> example habitats and then, by extension, to Apith habitat.
>
>> Actually, this line (and Jim's comments) give me a clue as to what is
>> going on here - you think I don't like your pictures because they
>> don't show much water :-)
>
> Pauline, your evasiveness is plainly obvious. It's as
> obvious as Jim Moore's or Mikey Brass's evasiveness
> when I asked them to explain their multi-niche nonsense
> (Mosaic theory).
Still having trouble understanding occupation of and adaptation to
multiple environments, eh.
> Real scientists don't fear
> explicitness, they embrace it.
Real scholars don't expect to be spoon-fed and follow up on the
references provided. Therefore I won't hold my breath for you to use your
library card.
--
===========
Mikey Brass
MA in Archaeology student
"The Antiquity of Man" http://www.antiquityofman.com
Book: "The Antiquity of Man: Artifactual, fossil and gene records
explored"
- "If we knew what we were doing, it wouldn't be called research, would
it?"
(Albert Einstein)
Pauline M Ross
>Pauline, your evasiveness is plainly obvious. It's as
>obvious as Jim Moore's or Mikey Brass's evasiveness
>when I asked them to explain their multi-niche nonsense
>(Mosaic theory). Real scientists don't fear
>explicitness, they embrace it.
Have you read the paper under discussion? Here's the reference again:
Kaye E Reed, 'Early hominid evolution and ecological change through
the African Plio-Pleistocene', JHE (1997) 32, 289-322
If you (or anyone) can show me where in that paper there is any lack
of explicitness which would be addressed by actual photographs (Bob's
or any others), I would be interested in hearing about it.
In fact, if you (or anyone) cared to discuss the paper at all, that
would be an improvement. Apart from Mikey (who read the paper the same
day he found out about it, immediately spotted some discrepancies, and
added some interesting background information, with references), no
one seems remotely interested in talking about the *substance* of the
paper at all.
--
Pauline Ross
Mikey Brass
news:lh87a01ell57gi07e...@4ax.com:
> In fact, if you (or anyone) cared to discuss the paper at all, that
> would be an improvement. Apart from Mikey (who read the paper the same
> day he found out about it, immediately spotted some discrepancies, and
> added some interesting background information, with references),
I read it late on a Friday night, after having arrived back from part-time
work ending at 10pm. I needed a break from my other readings and this
appealed to me.
> no one seems remotely interested in talking about the *substance* of the
> paper at all.
Unfortunately I do not have the time to go into the paper in detail as I'd
otherwise have liked. I'm now stacked up with dissertation readings.
Bob Keeter
SNippage. . . .
> Bob, you are completely missing the point. It's not about my pictures,
> or your pictures, it's about *any* pictures. I object to the
> *principle* of trying to match photographs of real places to Reed's
> example habitats and then, by extension, to Apith habitat. Can you not
> see how futile that is? Unless you have hopped in your time machine
> with a camera and nipped back 3 My, the whole exercise is pointless.
> And all the time we could be discussing Reed's actual paper.....
Well, in essence that is EXACTLY what Reed is attempting to do.
She is attempting to equate a modern environment, complete with
a nominal ecology of trees, grass, brush, water, rain and fauna
to an ancient environment, based on a series of bone collections.
In the modern biome, certain percentages of animals with certain
life styles show up. She looks at ancient collections, presumably
gathered in the same ways, and says that these percentages mean
that enviroment. Now, Im not going to say that the species are
the same (among the hominids we were talking apits, HE, paranthropus,
et al, and there is no need to presume anything other than similar
diversity over time for the gazelles, fish, birds, primates, etc when
compared over that range of time). At the same time, a given
"environment" should perhaps have the same general number of trees
per acre, the same nominal density of brush, the same abundance of
open water sources, the same proportions of open space to
closed forests, etc. Pictures define those. We dont have a good
photographic example of an "Open woodland/brushland transition"
from 3mya, but we have plenty from today. The analogies to
the bone collections and vegitation and water abundance and. . . .
all run together.
> And what on earth is a controversial environment, anyway???
Oh, Id say that a controversial environment is one where there is a
"gray scale" to be quibbled over. You and I both know exactly what
a swamp and a desert look like. We probably would prefer to see
a very different picture of an "open woodland" or a "treed savanna".
Those are the "controversial ones".
> >
> >You did get rather upset with me over the pictures that I turned up. . .
. .
> >There must have been a reason.
>
> Actually, this line (and Jim's comments) give me a clue as to what is
> going on here - you think I don't like your pictures because they
> don't show much water :-) Actually, I have to confess, I haven't
> looked at most of them (the links were broken, and I couldn't be
> bothered making the effort to fix them all), but I don't particularly
> care what they actually are. It's not relevant.
Its VERY relevant. Just as an example, if we define an open woodland
in terms of something pertinent to an apith it might be measured in terms
of the nominal distance to a tree from any point in the environment. If
our little furry cousin was never more than two or three running strides
from a nice climbable tree, he would be reasonably safe from the
big cats. On the other hand, if good safe climbing trees were spaced,
on an average, 200 meters apart, the cats might well be feasting! (unless
of course that scrawny little apith had a little help from such things
as sticks and/or stones and of course the brains to use them!)
I picked an easy parameter to visualize even without pictures, but Im
thinking that there are other factors that might only come to light when
that visual image is there. If I were to try to claim that the apiths had
NOTHING to fear in a given environment because climbing trees were
"plenty close", you would have every right to laugh if I did not back that
up with a distance. Distance between trees is not just a function of how
far an apith might be able to outsprint a lion, it also has to do with the
rainfall in an area, the oveall ecology of that area, in essence all
conveyed
in one way or another by a good picture. 8-)
Im pretty certain that you did not like the rather dry, dusty pictures that
came up showing what Reed had labeled an "open woodland/brushland".
There just plain would not be much room for swimming and wading, and
at a time before the nominally accepted invention of water carrying devices
(at least the ostrich egg canteens), this would mean a "dryland ape".
Hopefully, I can get you to show me that those environments designated
as "open woodland/brushland" by Reed (in our modern world) are
somehow more "amenable" to the AAH concepts. 8-)
> >Thats exactly and precisely right! West Lunga is a woodland/brushland,
> >and an example of a woodland/brushland, by her definition, is W. Lunga!
> >I have no problem with her definition, whatsoever. I just want to be
able
> >to accurately visualize what a "woodland brushland" looks like. How far
> >between trees, how much grass, how much brush, maybe even how much
> >open water! A picture does a lot of that.
>
> And the sketches in the paper itself give you exactly that (except the
> water, of course, which is shown by the proportion of aquatic
> species). Do you really want to talk about the paper, Bob, or do you
> find your pictures more interesting?
>
The paper itself is very interesting and I'm thinking more and more, a very
decent and insightful piece of analysis. If we cant at least agree on what
the paper says, at least as a common ground from which to extrapolate our
own hypotheses and conjectures, its just a replay of the blind men and the
elephant. That, Pauline, just does not appeal at all. That is just too
much
like Marc and Phillip standing off and calling each other fools because they
cant and never will agree on anything (except maybe for their dislike of me!
And that is something that, by the way, I treasure greatly! ;-0 ).
> >Er. . . . Why should hairlessness in humans be considered to be in the
least
> >related to an aquatic connection, when even the very close, very intimate
> >and very compelling "association" between fur seals and the sea has not
> >forced hairlessness?
>
> Because all the totally aquatic mammals are hairless, without
> exception. So clearly there is a connection.
Not unless you wish to put your aquatic primate in that same exact
"totally aquatic" clique. If you want to put him into the semi-aquatic
mammalian group, you have to attribute characterstics found in that
group. For example, if a modern animal has feathers, its a bird; because
all birds, and ONLY birds, have feathers. If ONLY completely aquatic
mammals are hairless, and man is hairless, humans must be aquatic, but
not by little bits! Formal logic AND observable physiologies both sort
of tilt the table a bit, wouldnt you say?
> [Snip table of eared seal distribution]
> >It would appear that there are some of those furry aquatic critters just
> >about
> >anywhere in the world, at just about all latitudes! Hmmmmmm.
>
> Except warm waters like the West Indies, SE Asia, the Philippines,
> etc. There are very few pinnipeds outside polar amd sub-polar regions.
Harbor seals live year round in the bays and coves of Baha California, the
Mediterranean, and the east coast of the US. California fur seals never see
even the sub-polar waters.
You dont have to believe me, look it up! I did and even provided the
pointers.
> >AND how the most obvious "fat deposits" (steatopygia), seem to be most
> >obvious in that same climate. SERIOUSLY dont think that steatopygia is
> >any possible adaptation to an aquatic environment.
>
> No one proposes that it is. But *all* human females have a lot of fat,
> the steatopygia is just an unusual way of positioning it, which is
> generally believed to be a response to a continuing need for that fat
> in a climate where carrying body fat is not normally advantageous. In
> other words, human body fat (of any sort) is unlikely to have evolved
> in a hot, dry climate.
Even though its most prominent display is in a hot dry climate? If we were
to
say that human body fat is a characteristic, just like "hairlessness" above,
could
we say that the environment where that characteristic is most enhanced, it
is most favored and therefore most likely to have been influenced and
selected for
in that environment? In one case, a fully aquatic environment seems to have
very
heavily favored the hairless since such a huge preponderance of hairless
mammals
inhabit that environment. If we look at the environment where human body
fat (for
whatever purpose) is most heavily favored from an evolutionary standpoint
(to eliminate
the local fast food joint), , it is. . . . . . . ???????? 8-) Fill in
the blank, please!
> >So, we have multiple examples of completely, or primarily aquatic
creatures
> >with significant fat deposits for insulation/floatation and we have at
least
> >one
> >example of a hominid with fat accumulations totally impossible to explain
by
> >too many trips to McDonalds for a "supersize". Do we use the cetacean
model
> >to explain human body fat or do we use the human example, at least in
> >terms of hypothesizing the purpose, i.e food cacheing or floatation?
Which
> >do YOU think is the best comparison to make?
>
> Multiple examples versus one example? I'd start with the multiple
> examples, wouldn't you?
Depends on the "closeness" of the comparison. If I have to reach across
multiple "least common ancestors" the comparison starts to loose its
clarity. Long skinny legs might be good indicators of rapid bursts of speed
in a cheetah, but compare them to the heavily muscled legs of a human
Olympic sprinter and there is very little similarity. Very similar
objectives but
totally different physiques to achieve the same goals! Now if you look
at big predatory cats, there is no doubt that a cheetah is much more
"built for speed" than an African lion. Same basic environment, VERY
different adaptation, and seriously, different selective "objectives".
> Here's another way of looking at it: fat is used for insulation,
> floatation and streamlining by aquatic mammals, and as a seasonal
> energy store by terrestrial mammals. Modern humans are terrestrial, so
> the energy store is where I'd look first. Only if that explanation is
> unconvincing would I start looking for an aquatic explanation. But as
> I've said before, the standard (energy-store) explanations are
> deficient (in my opinion), so an aquatic explanation is worth 'keeping
> on the table', so to speak.
At least here in the States, those who frequent fast food joints and
shy away from beaches and swimming pools would perhaps bring
that view into some serious question! 8-)
So long as its "on the table" and not nailed to the wall like some sort
of holy icon, termites can always get to it! ;-) Im almost begining
to hear some shades of "reasonable doubt". . . . better watch out
or you might find it far less palatable than you once did, so to speak
of course! ;-)
Regards
bk
Bob Keeter
"Mikey Brass" <mi...@nospam.antiquityofman.com> wrote in message
news:Xns94E8CBCDDBEBBmi...@195.8.68.217...
> Pauline M Ross <pmr...@ross-software.co.uk> wrote in
> news:lh87a01ell57gi07e...@4ax.com:
>
> > In fact, if you (or anyone) cared to discuss the paper at all, that
> > would be an improvement. Apart from Mikey (who read the paper the same
> > day he found out about it, immediately spotted some discrepancies, and
> > added some interesting background information, with references),
>
> I read it late on a Friday night, after having arrived back from part-time
> work ending at 10pm. I needed a break from my other readings and this
> appealed to me.
>
> > no one seems remotely interested in talking about the *substance* of the
> > paper at all.
>
> Unfortunately I do not have the time to go into the paper in detail as I'd
> otherwise have liked. I'm now stacked up with dissertation readings.
>
When you get a chance, Id be very interested in your intepretations!
Good luck with the readings!
Regards
bk
Jim McGinn
> > Pauline, your evasiveness is plainly obvious. It's as
> > obvious as Jim Moore's or Mikey Brass's evasiveness
> > when I asked them to explain their multi-niche nonsense
> > (Mosaic theory).
>
> Still having trouble understanding occupation of and adaptation to
> multiple environments, eh.
I know that such is impossible. I also know that
only somebody who is greatly ignorant about
evolutionary biology would fall for such an
obviously nonsensical notion.
>
> > Real scientists don't fear
> > explicitness, they embrace it.
>
> Real scholars don't expect to be spoon-fed and follow up on the
> references provided.
Evasive twit. There's nothing in those references,
jackass, that supports your dimwitted notion, you
imbecile. You anthropologists are nothing but smoke
and mirrors. The really funny thing is that your
understanding of evolutionary biology is so
nonexistent that you don't even have a sense of how
little you know.
> Therefore I won't hold my breath for you to use your
> library card.
You anthropologists are all the same. None of you
has the remotest clue as to how to address the
issues of human evolution. The only thing you know
is politics, specifically political correctness.
So that's the only game you will ever play.
Jim
Jim McGinn
> >Pauline, your evasiveness is plainly obvious. It's as
> >obvious as Jim Moore's or Mikey Brass's evasiveness
> >when I asked them to explain their multi-niche nonsense
> >(Mosaic theory). Real scientists don't fear
> >explicitness, they embrace it.
>
> Have you read the paper under discussion?
Yes, you sent it to me. And I already discussed
part of it with you.
> If you (or anyone) can show me where in that paper there is any lack
> of explicitness which would be addressed by actual photographs (Bob's
> or any others), I would be interested in hearing about it.
What is it about these pictures that give you
such trepidations?
>
> In fact, if you (or anyone) cared to discuss the paper at all, that
> would be an improvement. Apart from Mikey (who read the paper the same
> day he found out about it, immediately spotted some discrepancies, and
> added some interesting background information, with references), no
> one seems remotely interested in talking about the *substance* of the
> paper at all.
Pauline, you're a big phoney. You aren't interested
in discussing this paper. You are only interested
in discussing any words in this paper that lend
themselves, no matter how remotely, to your aquatic
fantasies.
Jim
Mikey Brass
news:qVToc.4836$zO3....@newsread2.news.atl.earthlink.net:
> When you get a chance, Id be very interested in your intepretations!
Afraid it can't happen. I post here yeah but the amount of reading and
analysis I have to do between now and Sept is unbelievable.
Paul Crowley
> . . . . *all* human females have a lot of fat,
> the steatopygia is just an unusual way of positioning it, which is
> generally believed to be a response to a continuing need for that fat
> in a climate where carrying body fat is not normally advantageous. In
> other words, human body fat (of any sort) is unlikely to have evolved
> in a hot, dry climate.
> Here's another way of looking at it: fat is used for insulation,
> floatation and streamlining by aquatic mammals, and as a seasonal
> energy store by terrestrial mammals. Modern humans are terrestrial, so
> the energy store is where I'd look first. Only if that explanation is
> unconvincing would I start looking for an aquatic explanation. But as
> I've said before, the standard (energy-store) explanations are
> deficient (in my opinion), so an aquatic explanation is worth 'keeping
> on the table', so to speak.
Read these two paragraphs again. First, you
state (correctly) that human _females_ have
lot of fat -- vastly more than males. But then
you forget that, drifting off into theories that
don't begin to consider that salient fact.
Are females supposed to
(a) need more insulation than males?
(b) need more flotation aid than males?
(c) need more streamlining?
(d) need a much larger seasonal energy store?
Each of those is manifest nonsense, so any
theory proposing (or assuming) any of them
should be rejected out of hand. The theory
that will work will do so because it focuses
on the supremely obvious facts.
The solution is, in fact, very simple.
What major need do females have,
which males don't?
Tough . . . eh?
The reason that the answer is not commonly
known . . . or even routinely assumed . .
is the same as that which I am always going
on about here. The PA profession consists
of males . . . and of females who have quite
unthinkingly taken over the male traditions
(and, maybe, prefer to think of themselves
as quasi-male).
Paul.
Marc Verhaegen
> Are females supposed to (a) need more insulation than males? (b) need
more flotation aid than males? (c) need more streamlining? (d) need a much
larger seasonal energy store?
Had you read the relevant literature you hadn't asked these questions:
From the issue of Nutrition & Health on AAT, Vol.9 (proceedings of the AAT
symposium at the BAAS Sciene Festival Week 1993), pp.165-191:
"... that in the transition stage from water to land, our ancestors were
gathering food in shallow water (lake margin, lagoon, sea coast). Since in
wading activities the lower body is more often immersed than the upper, the
female ("femoral") fat distribution may have been more suitable for
thermo-insulation while wading than the male (his "abdominal" fat possibly
improved his thermo-insulative or hydrodynamic streamlining while diving).
A sexual dimorphism in provision activities - men more diving, women more
wading - may have characterised our latest aquatic stage. Women have less
body hair, more superficial fat and a better thermo-insulation in water than
men (Hong & Rahn, 1967), which suggests that until recently they stayed in
the water during a greater part of the day. Even today, in most Oceanic
native societies, "there appears to have been a fairly sharp division of
fishing labour by sex: females did most of the gathering (usually by hand or
probing stick) of mollusks, crayfish and other creatures found in shallow
waters; males did most or all of the rest" (Oliver, 1989, 261), e.g., open
sea fishing by boat, underwater fishing, throwing harpoons (Oliver, 1989,
251-266)."
Paul Crowley
> > When you get a chance, Id be very interested in your intepretations!
>
> Afraid it can't happen. I post here yeah but the amount of reading and
> analysis I have to do between now and Sept is unbelievable.
It must be a real pain to have to learn all
that stuff off by heart. But -- remember --
it's all in a good cause. You will learn
never to have a thought pass through
your head. The basic rule, as you know
from your chants from the Great Ford,
is "PA people must never think"
And God forbid that you should ever
have an (ughh!) independent thought
in your brain, or even (oh, horrors!)
one critical of great sayings of your
honourable professors.
It warms the heart-strings to see
such powerful minds as yours, among
the new generation. In time, and with
such progress, we may get the studies
of Human Evolution back to where
they belong -- to a pre-Biblical stage.
I'm sure that it was that story about
Noah and his Ark that started all rot.
Paul.
Paul Crowley
>
> "Paul Crowley" <slkwuoiut...@slkjlskjoioue.com> wrote in message
> news:VO3pc.7746$qP2....@news.indigo.ie...
>
> > Are females supposed to (a) need more insulation than males? (b) need
> more flotation aid than males? (c) need more streamlining? (d) need a much
> larger seasonal energy store?
>
> Had you read the relevant literature you hadn't asked these questions:
At least AAT people do consider the issue
-- which is much more than can be said of
the brain-dead standard PA types.
The only trouble here is that the resulting
theories can only be described as fantastical.
> From the issue of Nutrition & Health on AAT, Vol.9 (proceedings of the AAT
> symposium at the BAAS Sciene Festival Week 1993), pp.165-191:
> "... that in the transition stage from water to land,
IF the relevant period was so long ago, it
would have little or no bearing on current
morphology. Females would have rapidly
lost fat in excess of requirements, and now
have no more than males.
> our ancestors were
> gathering food in shallow water (lake margin, lagoon, sea coast). Since in
> wading activities the lower body is more often immersed than the upper, the
> female ("femoral") fat distribution may have been more suitable for
> thermo-insulation while wading than the male (his "abdominal" fat possibly
> improved his thermo-insulative or hydrodynamic streamlining while diving).
That's next to crazy. But even if true, as
human populations moved away from
places where they did such things (and
say, moved up into mountains) they'd
lose the no-longer-desirable fat. There
are hundreds of human populations
which have made significant
morphological adaptations to their
local habitat or lifestyle:
bigger lungs, smaller digits, being taller
and thinner, being shorter and fatter,
whiter skin, much thinner hair (for most
non-Africans), growing beards, losing
beards, growing body hair . . .etc., etc.
Not one human population has females
with a lower requirement for body fat
(in order to become pregnant).
Your theory does not work.
> A sexual dimorphism in provision activities - men more diving, women more
> wading - may have characterised our latest aquatic stage.
That does not begin to explain the huge
difference in fat levels.
> Women have less body hair,
Not true for Africans -- and presumably
not true for human ancestors generally.
> more superficial fat and a better thermo-insulation in water than
> men (Hong & Rahn, 1967), which suggests that until recently they stayed in
> the water during a greater part of the day.
It might _suggest_ females did that. But
(a) What did their thin sticks of 5-year old
children do -- during all the time their
mothers were enduring the cold waters?
(b) How did these mothers cope with small
babies? Human mothers simply don't take
small babies into the sea -- knowing how
extremely dangerous it is.
(c) What is the point of spending hours
sitting in the sea? It does not put food
on the table.
The idea is beyond the nutty.
> Even today, in most Oceanic
> native societies, "there appears to have been a fairly sharp division of
> fishing labour by sex: females did most of the gathering (usually by hand or
> probing stick) of mollusks, crayfish and other creatures found in shallow
> waters; males did most or all of the rest" (Oliver, 1989, 261), e.g., open
> sea fishing by boat, underwater fishing, throwing harpoons (Oliver, 1989,
> 251-266)."
Sure, sure, women have more fat and can
take colder water better. But that is miles
away from saying that they EVOLVED in
that way for that reason. There is not a
single human population leading the kind
of lifestyle for which, and from which, you
say that morphology evolved. Nor is there
any good reason why (if what you say were
true) there should be such a total absence
of such populations.
Paul.
Mikey Brass
> "Mikey Brass" <mi...@nospam.antiquityofman.com> wrote in message
> news:Xns94E95BDFF98CEmi...@217.158.240.20...
>
>> > When you get a chance, Id be very interested in your intepretations!
>>
>> Afraid it can't happen. I post here yeah but the amount of reading and
>> analysis I have to do between now and Sept is unbelievable.
>
> It must be a real pain to have to learn all
> that stuff off by heart.
Actually I don't learn it off by heart. I read the reports, see what was
excavated at various sites, their dates, the geomorphology, the
construction techniques, the burials, the burial grave goods, the
economics of the spatial distributions, etc, and I am critiquing them as
well as placing them into a broad synthesis on a particular focused
topic. Naturally, being a Masters dissertation, I would be presenting
something new to the discipline.
> And God forbid that you should ever
> have an (ughh!) independent thought
> in your brain,
If archaeology students do not think critically for themselves, they
cannot and don't become archaeologists.
Don't let me spoil your fantasy, however.
Marc Verhaegen
> > > Are females supposed to (a) need more insulation than males? (b) need
more flotation aid than males? (c) need more streamlining? (d) need a much
larger seasonal energy store?
> > Had you read the relevant literature you hadn't asked these questions:
> At least AAT people do consider the issue-- which is much more than can be
said of the brain-dead standard PA types. The only trouble here is that the
resulting theories can only be described as fantastical.
Everybody knows it's hypothetical.
> > From the issue of Nutrition & Health on AAT, Vol.9 (proceedings of the
AAT symposium at the BAAS Sciene Festival Week 1993), pp.165-191: "... that
in the transition stage from water to land,
> IF the relevant period was so long ago
HOW long, you mean?? At least, try to be clear a bit.
>, it would have little or no bearing on current morphology.
Why??
> Females would have rapidly lost fat in excess of requirements, and now
have no more than males.
?? Why lost fat? why rapid?
> > our ancestors were gathering food in shallow water (lake margin, lagoon,
sea coast). Since in wading activities the lower body is more often immersed
than the upper, the female ("femoral") fat distribution may have been more
suitable for thermo-insulation while wading than the male (his "abdominal"
fat possibly improved his thermo-insulative or hydrodynamic streamlining
while diving).
> That's next to crazy. But even if true, as human populations moved away
from places where they did such things
They're still doing such things, man, see Oliver below.
> (and say, moved up into mountains) they'd lose the no-longer-desirable
fat. There are hundreds of human populations which have made significant
morphological adaptations to their local habitat or lifestyle: bigger lungs,
smaller digits, being taller and thinner, being shorter and fatter, whiter
skin, much thinner hair (for most non-Africans), growing beards, losing
beards, growing body hair . . .etc., etc.
Yes. And? Relevance?
> Not one human population has females with a lower requirement for body fat
(in order to become pregnant).
Yes. And?
> Your theory does not work.
I'm not interested in your opinion. You haven't given 1 argument against it.
> > A sexual dimorphism in provision activities - men more diving, women
more wading - may have characterised our latest aquatic stage.
> That does not begin to explain the huge difference in fat levels.
Same answer.
> > Women have less body hair,
> Not true for Africans -- and presumably not true for human ancestors
generally.
True for Africans.
> > more superficial fat and a better thermo-insulation in water than men
(Hong & Rahn, 1967), which suggests that until recently they stayed in the
water during a greater part of the day.
> It might _suggest_ females did that. But (a) What did their thin sticks
of 5-year old children do -- during all the time their mothers were enduring
the cold waters?
Sigh. Can't you even *read*?? If the mothers were wading, couldn't their
children being playing at the beach or also wading IYO?
> (b) How did these mothers cope with small babies? Human mothers simply
don't take small babies into the sea -- knowing how extremely dangerous it
is.
Why do you believe they lived solitary??
> (c) What is the point of spending hours sitting in the sea? It does not
put food on the table.
Sitting??
> The idea is beyond the nutty.
I have no idea what "nutty" is.
> > Even today, in most Oceanic native societies, "there appears to have
been a fairly sharp division of fishing labour by sex: females did most of
the gathering (usually by hand or probing stick) of mollusks, crayfish and
other creatures found in shallow waters; males did most or all of the rest"
(Oliver, 1989, 261), e.g., open sea fishing by boat, underwater fishing,
throwing harpoons (Oliver, 1989, 251-266)."
> Sure, sure, women have more fat
Yes.
>and can take colder water better.
Can they?? Refs, please.
> But that is miles away from saying that they EVOLVED in that way for that
reason.
Again: everybody knows this is hypothetical, but so far you completely fail
to give 1 argument why it would be wrong.
> There is not a single human population leading the kind of lifestyle
I'm not interested in your opinion. Read Oliver. Or Gislen below.
> for which, and from which, you say that morphology evolved.
I'm not saying that. I'm pointing to the possibility.
> Nor is there any good reason why (if what you say were true) there should
be such a total absence of such populations.
Sigh. I suggest you should first inform a little before producing your usual
empty blabla. Start with, eg, www.nature.com/nsu/030512/030512-14.html
A Gislén, EJ Warrant & RHH Kröger 2003 "Voluntary accommodation improves
underwater vision in children" A Gislén "Superior underwater vision in
humans" Lund Univ
- Purpose: Sea in a tribe of sea-gipsies from SE.Asia have been found to
have superior underwater vision compared to Eur.children. They achieve this
by accommodating heavily & constricting their pupils underwater. As
accommodation is not normally elicited in the blurry underwater environment,
these children may have learned to accommodate voluntarily. If so, it could
be possible forl Eur.children to acquire this ability as well.
- Methods: 4 Eur.children were trained with sinusoidal gratings in an indoor
pool. Both acuity & contrast sensitivity were determined before & after
training. Pupil size was measured on land & underwater , pupil constriction
was used as an indication of accommodation.
- Results: All children improved their underwater visual acuity during the
training period, though learning speed & attained level of skull differed. 5
months after the first training session, all children showed distinct burst
of pupil constriction underwater, indicating they had learned to control
accommodation. When tested in an outdoor pool in bright sunlight -
comparable to light environments in SE.Asia - we found the children had
attained the same level of underwater acuity as the sea-gypsy children.
- Conclusions: The superior underwater vision of the sea gypsys can be
attributed to a learned ability to control accommodation. Eur.children also
have the ability to learn this, but the process takes more or less time
depending on the individual. This is the first example where voluntary
accommodation has been shown to be of practical use for a population that
depend on improved underwater acuity for their survival.
Anna Gislén, Marie Dacke, Ronald HH Kröger, Maths Abrahamsson, Dan-Eric
Nilsson & Eric J Warrant 2003 "Superior Underwater Vision in a Human
Population of Sea Gypsies" Curr.Biol.13:833-6
Humans are poorly adapted for underwater vision. In air, the
curved corneal surface accounts for 2/3 of the eye's refractive power, and
this is lost when air is replaced by water. Despite this, some tribes of sea
gypsies in SE.Asia live off the sea, and the children collect food from the
sea floor without the use of visual aids. This is a remarkable feat when one
considers that the human eye is not focused underwater and small objects
should remain unresolved. We have measured the visual acuity of children in
a sea gypsy population, the Moken, and found that the children see much
better underwater than one might expect. Their underwater acuity (6.06
cycles/°) is more than twice as good as that of European children (2.95
cycles/°). Our investigations show that the Moken children achieve their
superior underachieve water vision by maximally constricting the pupil (1.96
mm compared to 2.50 mm in European children) and by accommodating to the
known limit of human performance (15-16 D). This extreme reaction-which is
routine in Moken children-is completely absent in European children. Because
they are completely dependent on the sea, the Moken are very likely to
derive great benefit from this strategy.
Pauline M Ross
<slkwuoiut...@slkjlskjoioue.com> wrote:
>Read these two paragraphs again. First, you
>state (correctly) that human _females_ have
>lot of fat -- vastly more than males. But then
>you forget that, drifting off into theories that
>don't begin to consider that salient fact.
You're right, of course. I was being brief because Bob and I have gone
over all this many times before. And you are absolutely right to keep
reminding us all about the women and children.
Let me try again: all modern humans have a substantial amount of fat,
much more than our closest cousins. The numbers I have seen are 15-20%
for adult males and 20-25% for adult females, compared with 5% for a
chimp, but these numbers are anecdotal. Infants also have a lot of
fat, which begins to be laid down some 2 months before birth and lasts
for approximately 4 years. Adult females acquire their extra fat at
puberty, and a certain amount is required for fertility.
So whatever scenario anyone comes up with has to take account of all
these facts. It is clear that adult female fat is connected with
reproduction in modern humans, but the reasons for that situation and
for infant fat and human body fat generally are debateable.
In terrestrial species, body fat is normally a seasonal energy store,
and (since modern humans are terrestrial) that is why I suggest that
that would be the first place to look for a cause. However, there is
no one reason which adequately accounts for the different fat levels
in infants, children and adult males, and adult females.
--
Pauline Ross
Pauline M Ross
wrote:
>[Reed] is attempting to equate a modern environment, complete with
>a nominal ecology of trees, grass, brush, water, rain and fauna
>to an ancient environment, based on a series of bone collections.
>In the modern biome, certain percentages of animals with certain
>life styles show up. She looks at ancient collections, presumably
>gathered in the same ways, and says that these percentages mean
>that enviroment.
Yes, sort of. She tests her analysis methods by trying them out on
known modern bone assemblages. And they work, so she feels confident
about applying those methods to fossil assemblages.
>Oh, Id say that a controversial environment is one where there is a
>"gray scale" to be quibbled over. You and I both know exactly what
>a swamp and a desert look like. We probably would prefer to see
>a very different picture of an "open woodland" or a "treed savanna".
>Those are the "controversial ones".
I don't have preferences regarding what they look like, but I do like
to know what people mean when they use expressions like 'open
woodland' or 'treed savanna'. Luckily, Reed defines her terms very
precisely.
[Re those photographs]
>Its VERY relevant. Just as an example, if we define an open woodland
>in terms of something pertinent to an apith it might be measured in terms
>of the nominal distance to a tree from any point in the environment. If
>our little furry cousin was never more than two or three running strides
>from a nice climbable tree, he would be reasonably safe from the
>big cats. On the other hand, if good safe climbing trees were spaced,
>on an average, 200 meters apart, the cats might well be feasting! (unless
>of course that scrawny little apith had a little help from such things
>as sticks and/or stones and of course the brains to use them!)
OK, let's talk about tree spacings, as an example. Reed's drawings of
her 8 example habitats (p295) are vertically to scale. She doesn't
define a horizontal scale, but if we assume it is the same scale, then
we can see that in 'closed woodland' the trees are 15-30 ft apart, in
'open woodland' more than 60 ft apart, and in 'grassland' even further
apart. What would a photograph add to that?
> Distance between trees is not just a function of how
>far an apith might be able to outsprint a lion, it also has to do with the
>rainfall in an area, the oveall ecology of that area, in essence all
>conveyed in one way or another by a good picture. 8-)
Well, you can't see the rainfall from a photograph, can you? Nor the
overall ecology, only a single viewpoint on a single day of the year.
>
>Im pretty certain that you did not like the rather dry, dusty pictures that
>came up showing what Reed had labeled an "open woodland/brushland".
I don't remember a specific picture like that, but if you are talking
about West Lunga, Reed describes it as "closed woodland/bushland
transition". It's hard to understand what you are saying when you
switch between 'open' and 'closed'.
>There just plain would not be much room for swimming and wading, and
>at a time before the nominally accepted invention of water carrying devices
>(at least the ostrich egg canteens), this would mean a "dryland ape".
>Hopefully, I can get you to show me that those environments designated
>as "open woodland/brushland" by Reed (in our modern world) are
>somehow more "amenable" to the AAH concepts. 8-)
This is why I think that photographs of modern environments can be
misleading. I don't remember the exact picture you're talking about,
but imagine that you are parachuted into West Lunga with your digital
camera to take a picture. Firstly, how big do you suppose it is? (I
have no idea, but I would guess quite big). Do you think the whole
area is "closed woodland/bushland transition"? Do you think the
woodland and bushland are uniformly arranged? Do you think there are
no patches of forest or open woodland or rivers anywhere around? Which
way would you point your camera to get a representative shot? This way
the trees may be too close together or too far apart, that way perhaps
there is only bushland with no trees. Do you think there is any way
you could take a single photograph which would represent "closed
woodland/bushland transition" which would *not* be your subjective
interpretation of what that looks like? And why would that add
anything at all to Reed's descriptions of closed woodland and
bushland?
This is why I say that your photographs are not relevant. The only way
a photograph could truly represent *Reed's* idea of closed woodland
and bushland is if it matched exactly in size, scale and plant
distribution with her drawings, in which case it would add nothing at
all. If it differed in any way, it would be misleading.
As to whether an Apith habitat would or would not have room for
swimming and wading, Reed found that they lived in "fairly wooded,
well-watered regions" (the details of the specific fossils on p316
mention "deltaic flood plain", "edaphic grasslands" and "riverine
forest"). These wetter areas don't show up in her example drawings,
and probably aren't in your photographs either, but nevertheless they
are there.
Whether they actually swam or waded is entirely open to conjecture,
but the water was certainly there. Reed concludes (p316 again) that
"the habitats in which these hominids could exist are constrained by
minimum and maximum amounts of rainfall and tree cover", and
speculates that perhaps a change to drier, more open habitats after
2.8 Mya actually lead to their extinction.
>The paper itself is very interesting and I'm thinking more and more, a very
>decent and insightful piece of analysis. If we cant at least agree on what
>the paper says, at least as a common ground from which to extrapolate our
>own hypotheses and conjectures, its just a replay of the blind men and the
>elephant.
I don't at present see any point of disagreement between us over what
the paper says, since we haven't really discussed it. We discussed the
abstract at great length, and we have talked about your photographs,
also at great length, but it would be nice to discuss the paper
itself. Do you see any problems with her methodology? Do you disagree
with her interpretation of her results? Mikey Brass saw one or two
problems with it - do you agree with his assessment? What do you think
of his description of Swartkrans as 'mosaic' (Paranthopus, not
Australopithecus, of course)?
>> >[Bob]Er. . . . Why should hairlessness in humans be considered to be in the
>least
>> >related to an aquatic connection, when even the very close, very intimate
>> >and very compelling "association" between fur seals and the sea has not
>> >forced hairlessness?
>>
>> [Pauline]Because all the totally aquatic mammals are hairless, without
>> exception. So clearly there is a connection.
>
>Not unless you wish to put your aquatic primate in that same exact
>"totally aquatic" clique.
No, it simply means that there is some sort of relationship between
hairlessness and aquaticism, in other words, aquaticism is *one* of
the possible causes for hairlessness. This is indisputable. The
question of whether this applies to humans is another issue entirely,
and is (clearly) much more debateable, but it does indicate that
aquaticism is one option worthy of consideration, that's all. If you
want to say that it can't apply to us because only the fully-aquatic
mammals are hairless (and a small number of semi-aquatics), that's
fine, but it means you have to find a different explanation.
Burrowing? Large body size? Or a unique-to-humans explanation? Hmm...
>> >[Bob]It would appear that there are some of those furry aquatic critters just
>> >about
>> >anywhere in the world, at just about all latitudes! Hmmmmmm.
>>
>>[Pauline] Except warm waters like the West Indies, SE Asia, the Philippines,
>> etc. There are very few pinnipeds outside polar amd sub-polar regions.
>
>Harbor seals live year round in the bays and coves of Baha California, the
>Mediterranean, and the east coast of the US. California fur seals never see
>even the sub-polar waters.
Bob, the words "very few" does not mean none. Of course there are some
species of pinnipeds in warm waters, but there are *very few* of them.
The vast majority of pinniped species are in polar or sub-polar
waters.
[Re steatopygia and body fat not having evolved in a hot climate]
>Even though its most prominent display is in a hot dry climate?
[Snip]
Steatopygia may be the most prominent display of body fat, but it is a
highly unusual arrangement. All humans have body fat, particularly
infants and females, and most carry it dispersed around their bodies.
A few humans in hot climates have a different arrangement, where
female body fat accumulates preferentially on the buttocks. This
suggests that 1) female body fat is essential (but we knew that
anyway), and 2) in a hot climate overall body fat is disadvantageous
(but we knew that too), and 3) in such cases, the essential fat will
be redistributed to where it is least disadvantageous.
In other words, it is most unlikely that the standard, overall type of
body fat could have evolved in a hot, dry climate.
>>[Pauline] But as
>> I've said before, the standard (energy-store) explanations are
>> deficient (in my opinion), so an aquatic explanation is worth 'keeping
>> on the table', so to speak.
>
>At least here in the States, those who frequent fast food joints and
>shy away from beaches and swimming pools would perhaps bring
>that view into some serious question! 8-)
Yes, we have to be careful to exclude overfed modern humans from the
equation, although it can be difficult to know exactly what fat a
'typical' pre-agricultural human might have had.
>
>So long as its "on the table" and not nailed to the wall like some sort
>of holy icon, termites can always get to it! ;-) Im almost begining
>to hear some shades of "reasonable doubt". . . . better watch out
>or you might find it far less palatable than you once did, so to speak
>of course! ;-)
Sometimes I wonder if you read what I write, Bob. Do you remember the
'Plausible AAT ideas' post, where I laid out what I thought were the
deficiencies in *all* the currently viable ideas for bipedalism,
hairlessness and fat? That included the problems in the AAH scenarios.
Of course there's reasonable doubt! Any degree of certainly leaves
science behind, doesn't it?
All I am saying is that *at the moment* I find the AAH proposals *more
plausible* than any of the conventional alternatives. Mind you, that
may say more about the current state of PA than about the AAH :-) I'm
quite happy for you or anyone else to hold a different viewpoint, and
I'm not trying to convince anyone. Quite the reverse - I would really
like someone to convince *me* just why one of the conventional
explanations for (say) bipedalism is more plausible than the wading
idea.
--
Pauline Ross
Bob Keeter
Snip. . .
> You're right, of course. I was being brief because Bob and I have gone
> over all this many times before. And you are absolutely right to keep
> reminding us all about the women and children.
>
Brief? Now perhaps you are "playing with words"! Still, I promised that
I was going to do my best to make you think some "uncomfortable" thoughts
about your evolutionary ideas, so. . . . . das ist goot! ;-)
> Let me try again: all modern humans have a substantial amount of fat,
> much more than our closest cousins. The numbers I have seen are 15-20%
> for adult males and 20-25% for adult females, compared with 5% for a
> chimp, but these numbers are anecdotal. Infants also have a lot of
> fat, which begins to be laid down some 2 months before birth and lasts
> for approximately 4 years. Adult females acquire their extra fat at
> puberty, and a certain amount is required for fertility.
OK. That first sentence is pretty positive. There are plenty of sources
for the average body fat content for modern humans in an industrial
society. There are very few (if any) equally comprehensive sources
for data on the same parameter for modern humans in primitive societies.
I've been able to find NO real references for the body fat content
of chimps. IF you can provide some support for that 5%, and maybe
even a shreadout by adult male / adult female / child for the chimps
you could probably win a point or two in the debate, particularly if
the numbers were significantly different from primitive society humans.
Since human fat content amongst "traditional societies" tends to strongly
correlate to latitude, lets limit those human societies to
tropical/subtropicals.
Say, !Kung, Aborigines, Amazonian and Orinoco tribes, Negritos,
Andaman Islanders and also eliminate those that have abandoned
the primitive diet for McDonalds!
I agree that your average wild chimp probably has very little body
fat compared to the average Bostonian or Londoner, but if we bother
to compare apples to pears instead of watermellons and look at the
human primative societies, it might be a lot less spread. Maybe not
enough to support such strong statements.
For that matter if you consider modern athletes, I suspect that you will
see very different numbers for body fat. Is the physical conditioning
of a modern athlete all that much different from the inherent physical
conditioning of a wild chimp? Well, except for the fact that the goal
in one case is medals and trophies, and in the other, its food and
survival!
> So whatever scenario anyone comes up with has to take account of all
> these facts. It is clear that adult female fat is connected with
> reproduction in modern humans, but the reasons for that situation and
> for infant fat and human body fat generally are debateable.
This is very good! You have agreed to the connection between adult
female body fat and reproduction! That tie-in is VITAL I think.
Lets think in terms of food supply, and the natural checks and
balances that we see in nature with respect to reproductive fertility.
A well-fed adult female in a primitive setting is probably a pretty
solid "indicator" of good times; times where the "inventment" in
a baby would be a good risk to the family group. Babies born to
women with significant body fat both have the advantage of that
food cache and also perhaps a survival advantage once delivered.
"Survival advantage" is what its all about, right? Characteristics
that provide some small, but still significant survival advantage
tend to be acquired, right? And at least according to your above
there is an undebatable indication that there IS a connection between
human body fat and human reproduction.
Could this be the connection? Why not?
>
> In terrestrial species, body fat is normally a seasonal energy store,
> and (since modern humans are terrestrial) that is why I suggest that
> that would be the first place to look for a cause. However, there is
> no one reason which adequately accounts for the different fat levels
> in infants, children and adult males, and adult females.
>
Might be hard to prove, one way or another, until some data is in
on the chimps, but lets see if there is a "pattern". Lets separate
those classes you laid out into two groups. The first group is adult
females and infants, the second is adult males and pre-adolescent
children. You can draw in the precise line between infants and
pre-adolescent rather arbitrarily, but I would suggest that for
modern humans it might be at 4 or 5 years of age for lack of a
better point. Then lets just logically think about the energy demannds
of both groups, and Im not talking about the sudden brief
expenditures that would occur during a hunting sprint or during
a childhood game. Im talking about the level of demand over
months and years.
Males and adolescents need enough food energy of course
to survive and perform whatever tasks they perform in the
society, with perhaps a few more calories per pound for the
adolescents physical growth, but its a pretty steady level.
Females of the species on the other hand, usually have rather
large and obvious "weight gain" with pregnancy, so long as
adequate food is available, plus a "standing reserve" significantly
higher than the average male. Infants ALSO have a rather
larger fat reserve.
Could it be that in the mother's case, the reserves have evolved
to support the very rapid physical growth that occurs both en utero
where the mother is solely responsible for nutrition) and after birth
(where for an extended period of time the mother is still responsible)
in infants. For the infants, there is I suspect a period immediately
after birth where the energy demands are very high and the digestive
system is not yet fully "on line". I can speak to this at least in
one case very definitively, since my son lost nearly two pounds of
weight in the first three weeks of life. He was having trouble
digesting his formula and only the care of modern hospital saved
him. (He's a big strapping kid, 6-1, 180lbs now, but then he
looked a lot like some little emaciated escapee from Aushwitz)
If he had not been born with a significant body fat deposit,
he would have died within days of birth, at least in a primitive
society. In his case, it just took a bit longer for the digestive
machinery to spin up, now he digests anything short of long-
string cellulose just fine!
Speaking of cellulose, noticed any signficant termite gnawing
recently! ;-)
Regards
bk
Bob Keeter
> On Thu, 13 May 2004 23:52:23 GMT, "Bob Keeter" <rke...@earthlink.net>
> wrote:
>
> >[Reed] is attempting to equate a modern environment, complete with
> >a nominal ecology of trees, grass, brush, water, rain and fauna
> >to an ancient environment, based on a series of bone collections.
> >In the modern biome, certain percentages of animals with certain
> >life styles show up. She looks at ancient collections, presumably
> >gathered in the same ways, and says that these percentages mean
> >that enviroment.
>
> Yes, sort of. She tests her analysis methods by trying them out on
> known modern bone assemblages. And they work, so she feels confident
> about applying those methods to fossil assemblages.
>
So, if we are to infer a "class" of environment from the bone assembleges
what does that mean? Does it mean that this mix indicates a certain set
of parameters about the environment? (rhetorical) What parameters DOES
it indicate about the two environments (paleo and modern) other than the
assigned name?
> >Oh, Id say that a controversial environment is one where there is a
> >"gray scale" to be quibbled over. You and I both know exactly what
> >a swamp and a desert look like. We probably would prefer to see
> >a very different picture of an "open woodland" or a "treed savanna".
> >Those are the "controversial ones".
>
> I don't have preferences regarding what they look like, but I do like
> to know what people mean when they use expressions like 'open
> woodland' or 'treed savanna'. Luckily, Reed defines her terms very
> precisely.
AND provides references to modern locations that match her descriptions!
> [Re those photographs]
> >Its VERY relevant. Just as an example, if we define an open woodland
> >in terms of something pertinent to an apith it might be measured in terms
> >of the nominal distance to a tree from any point in the environment. If
> >our little furry cousin was never more than two or three running strides
> >from a nice climbable tree, he would be reasonably safe from the
> >big cats. On the other hand, if good safe climbing trees were spaced,
> >on an average, 200 meters apart, the cats might well be feasting!
(unless
> >of course that scrawny little apith had a little help from such things
> >as sticks and/or stones and of course the brains to use them!)
>
> OK, let's talk about tree spacings, as an example. Reed's drawings of
> her 8 example habitats (p295) are vertically to scale. She doesn't
> define a horizontal scale, but if we assume it is the same scale, then
> we can see that in 'closed woodland' the trees are 15-30 ft apart, in
> 'open woodland' more than 60 ft apart, and in 'grassland' even further
> apart. What would a photograph add to that?
>
Why assume anything? A photo removes any need for the assumption and
I dont believe that the photos would differ materially from your own
discriptive words above, although the distances might be spread out a
bit more, the relative relationships are right. The only problem
comes when those distances start to get large, perhaps in that open
woodland/brushland transition lets say. I think that Reed's study suggests
that this kind of environment might be very important at least in the
transition from the pre-hominids and lets say the first Homo. I would
expect that the inter-tree distance for this zone would be a rather smooth
transition between the "pure" open woodland, and the "pure brushland".
I at least need to be able to visualize this. To use your number, a 60 ft
spacing between trees in Wales is a very different environment than a
60 ft spacing between trees in the Natal. Its not any ONE parameter
that the picture brings, its a host of parameters in one visual rendering.
(And we dont have to guess on the horizontal scale! 8-) )
> > Distance between trees is not just a function of how
> >far an apith might be able to outsprint a lion, it also has to do with
the
> >rainfall in an area, the oveall ecology of that area, in essence all
> >conveyed in one way or another by a good picture. 8-)
>
> Well, you can't see the rainfall from a photograph, can you? Nor the
> overall ecology, only a single viewpoint on a single day of the year.
Very, very true! Thats why a real study would provide pictures over
a long period of time, or at least a verbal description of "dry season"
monsoon season, or whatever. If we assumed that the Serengeti
aways looked like the wet season or the wet season exclusively it would be
a very sad assumption. Still, unless you want to hypothesize a
largely migratory existence, like the Serengeti grazers, a species in the
environment must be able to survive for months in either extreme.
> >
> >Im pretty certain that you did not like the rather dry, dusty pictures
that
> >came up showing what Reed had labeled an "open woodland/brushland".
>
> I don't remember a specific picture like that, but if you are talking
> about West Lunga, Reed describes it as "closed woodland/bushland
> transition". It's hard to understand what you are saying when you
> switch between 'open' and 'closed'.
>
My mistake! Used the wrong word. The question remains, were the pictures
uncomfortably dry for the open/closed woodlands and brushlands? Why?
Could it be that many of Reed's much more specific definitions of the
environments started to look much more like what many people think of when
they use the completely generic "savanna"? To give a "tree spacing" even if
specifically stated and not guestimated from an unstated horizontal scale
on some hand sketches, hardly conveys the "full picture" doe it? 8-)
> >There just plain would not be much room for swimming and wading, and
> >at a time before the nominally accepted invention of water carrying
devices
> >(at least the ostrich egg canteens), this would mean a "dryland ape".
> >Hopefully, I can get you to show me that those environments designated
> >as "open woodland/brushland" by Reed (in our modern world) are
> >somehow more "amenable" to the AAH concepts. 8-)
>
> This is why I think that photographs of modern environments can be
> misleading. I don't remember the exact picture you're talking about,
> but imagine that you are parachuted into West Lunga with your digital
> camera to take a picture. Firstly, how big do you suppose it is? (I
> have no idea, but I would guess quite big).
Actually, its 1684 square kilometers! 8-) and actually quite diverse.
A detailed discription can be found at:
http://www.sunvil.co.uk/africa/zambia/guidebook/ch17.htm#WEST%20LUNGA%20NATIONAL%20PARK
from where I will quote:
"WEST LUNGA NATIONAL PARK
150km northwest of Kafue, as the pied crow flies, West Lunga is another of
Zambia's parks which is ideal for small expeditions to explore, although not
practical to visit casually. Check with the National Parks and Wildlife
Service for the latest news about the park (there is an office at Solwezi if
you are approaching from the north) and don't arrive without the backing of
several vehicles for safety in the event of an emergency. There are no camps
here, or commercial operators, or even scouts inside the park - so you must
get around independently.
GEOGRAPHY, FAUNA AND FLORA
West Lunga National Park covers 1,684km² of forests, dambos, open grasslands
and papyrus swamps. It is bounded by the Kabompo River to the south
(adjacent to which are most of the park's swamps) and by the West Lunga
River to the west.
Despite persistent local poaching, the park still harbours elephant,
buffalo, lion, leopard, hippopotamus and a wide range of antelope including
puku, sitatunga, blue, common and yellow-backed duiker, sable, bushbuck and
defassa waterbuck. "
No pictures though, so I guess its ok, right? This even matches up with
Reed's description of a pretty diverse ecology, right?
> Do you think the whole
> area is "closed woodland/bushland transition"? Do you think the
> woodland and bushland are uniformly arranged? Do you think there are
> no patches of forest or open woodland or rivers anywhere around? Which
> way would you point your camera to get a representative shot?
I would personally point the camera in all directions, but since Im not the
photographer Id have to take what I can get and not automatically, and
perhaps a bit paranoid, worry about whether the photographer had the
secret hidden agenda of making the environment look wetter or dryer solely
to prove someone else's point in a USENET debate! What is wrong with
"face value"?
> This way
> the trees may be too close together or too far apart, that way perhaps
> there is only bushland with no trees. Do you think there is any way
> you could take a single photograph which would represent "closed
> woodland/bushland transition" which would *not* be your subjective
> interpretation of what that looks like? And why would that add
> anything at all to Reed's descriptions of closed woodland and
> bushland?
>
No. Yes. I the second case, it at least represents ONE example of what
the author was including in that rather large and admittedly widely diverse
category. When later on, she states that a given hominid species is found
in a specific environment, I want to be able to include ALL of the range of
that environment into my understanding, not just the dry practically
treeless
"edge" of the open woodland/brushland transition, and NOT the well-treed
wet "edge". She is saying that between these "bounds" it does not make
since to distinguish (or her data does not support that much resolution).
I want to know the range of possible interpretations of "open woodland"
and the best way is with a picture!
> This is why I say that your photographs are not relevant. The only way
> a photograph could truly represent *Reed's* idea of closed woodland
> and bushland is if it matched exactly in size, scale and plant
> distribution with her drawings, in which case it would add nothing at
> all. If it differed in any way, it would be misleading.
>
But IF I am catching the drift, the only way to assess the "matching" is
if the spacing shown in the photograph matched your estimation of the
spacing from the drawings? 8-) Is this good science, Pauline?
Which is more misleading, ASSUMING a horizontal spacing for trees
from a drawing that makes no claims whatsoever for the horizontal
scale, or a photograph of an area that is specifically stated to represent
a given environment?
> As to whether an Apith habitat would or would not have room for
> swimming and wading, Reed found that they lived in "fairly wooded,
> well-watered regions" (the details of the specific fossils on p316
> mention "deltaic flood plain", "edaphic grasslands" and "riverine
> forest"). These wetter areas don't show up in her example drawings,
> and probably aren't in your photographs either, but nevertheless they
> are there.
>
Pauline, W. Lunga has papyrus swamps! At last in small localized areas.
I just want to get a full and complete meaning of what an "open woodland
/brushland transition" means, if it means a much wetter than I expected
or much dryer than you preferred environment it really doesnt matter
except in terms of how it helps me (or perhaps even you) to interpret
what the author said.
> Whether they actually swam or waded is entirely open to conjecture,
> but the water was certainly there. Reed concludes (p316 again) that
> "the habitats in which these hominids could exist are constrained by
> minimum and maximum amounts of rainfall and tree cover", and
> speculates that perhaps a change to drier, more open habitats after
> 2.8 Mya actually lead to their extinction.
Yep. AND, tree cover is one of the big players. I dont remember any
definition of that other than to say that the tree cover is defined by a
category like "closed woodland", and then that "closed woodland" is
represented by a sketch and a list of modern examples.
I like one particular method of defining it since it does not require me to
imagine that I can extract a horizontal spacing from a sketch that does not
show horizontal spacing! Sorry, you loose me here.
> >The paper itself is very interesting and I'm thinking more and more, a
very
> >decent and insightful piece of analysis. If we cant at least agree on
what
> >the paper says, at least as a common ground from which to extrapolate our
> >own hypotheses and conjectures, its just a replay of the blind men and
the
> >elephant.
>
> I don't at present see any point of disagreement between us over what
> the paper says, since we haven't really discussed it. We discussed the
> abstract at great length, and we have talked about your photographs,
> also at great length, but it would be nice to discuss the paper
> itself.
Oh, I think that we disagree on several points, but those are mainly in
the places where one or the other of us tries to diverge too much from
what is actually SAID.
> Do you see any problems with her methodology?
The basic methodology would appear to be quite sound. I would have liked
to have seen more of the data presented (I strongly suspect that the data
shown was only a sample of what she actually used). If the data presented
actually represents the "full set" I would have used "small sample size"
statistics instead of the classic "large sample size" methods that she
apparently
used, but Im not at all certain that the conclusions would have been much
different (the mathematical confidence in the results would have been a bit
less I think).
> Do you disagree with her interpretation of her results? Mikey Brass saw
> one or two problems with it - do you agree with his assessment?
If his "problems" were with the description of the fossil assembleges,
dating
of those, or things of that nature, I would automatically defer to his
judgement.
If his problems were with the statistics used, Id need to talk to him and
find
out what caught his eye. If its just a matter of questioning the overall
logic
of the study or conclusions, I would have to get the details and perhaps go
"for" or "against" depending on what his views are. Still, Mikey is a
pretty
sharp, well-educated, and very current student of African paleoanthropology.
Going against his assessment might be pretty embarassing Id think. 8-)
Mikey, does that get me a discount on the next book? ;-))
> What do you think of his description of Swartkrans as 'mosaic'
> (Paranthopus, not Australopithecus, of course)?
I think that any of these 'transitional' environments were by definition a
mosaic. Check out the Zambian description of W. Lunga. The important
issue would be the "ratios". Again its that gradient between obvious rain
forest and obvious grassland.
SNip. . .
> >> [Pauline]Because all the totally aquatic mammals are hairless, without
> >> exception. So clearly there is a connection.
> >
> >Not unless you wish to put your aquatic primate in that same exact
> >"totally aquatic" clique.
>
> No, it simply means that there is some sort of relationship between
> hairlessness and aquaticism, in other words, aquaticism is *one* of
> the possible causes for hairlessness. This is indisputable. The
> question of whether this applies to humans is another issue entirely,
> and is (clearly) much more debateable, but it does indicate that
> aquaticism is one option worthy of consideration, that's all. If you
> want to say that it can't apply to us because only the fully-aquatic
> mammals are hairless (and a small number of semi-aquatics), that's
> fine, but it means you have to find a different explanation.
> Burrowing? Large body size? Or a unique-to-humans explanation? Hmm...
>
Pauline, if all known examples of hairlessness in aquatic and semi-aquatic
species
are fully, and completely aquatic, does that not mean that if you are to
ascribe
human hairlessness to an aquatic existence that you must buy the whole deal?
Hairlessness is not a characteristic of mammals that spend time in the water
and
time on land. It is ONLY a characteristic of mammals that spend practically
ALL of
their time in the water or never come out of the water at all!
> >> >[Bob]It would appear that there are some of those furry aquatic
critters just
> >> >about
> >> >anywhere in the world, at just about all latitudes! Hmmmmmm.
> >>
> >>[Pauline] Except warm waters like the West Indies, SE Asia, the
Philippines,
> >> etc. There are very few pinnipeds outside polar amd sub-polar regions.
> >
> >Harbor seals live year round in the bays and coves of Baha California,
the
> >Mediterranean, and the east coast of the US. California fur seals never
see
> >even the sub-polar waters.
>
> Bob, the words "very few" does not mean none. Of course there are some
> species of pinnipeds in warm waters, but there are *very few* of them.
> The vast majority of pinniped species are in polar or sub-polar
> waters.
>
As are the vast majority of cetaceans, at least on a seasonal basis. . . .
..
> [Re steatopygia and body fat not having evolved in a hot climate]
> >Even though its most prominent display is in a hot dry climate?
> [Snip]
> Steatopygia may be the most prominent display of body fat, but it is a
> highly unusual arrangement. All humans have body fat, particularly
> infants and females, and most carry it dispersed around their bodies.
> A few humans in hot climates have a different arrangement, where
> female body fat accumulates preferentially on the buttocks. This
> suggests that 1) female body fat is essential (but we knew that
> anyway), and 2) in a hot climate overall body fat is disadvantageous
> (but we knew that too), and 3) in such cases, the essential fat will
> be redistributed to where it is least disadvantageous.
>
> In other words, it is most unlikely that the standard, overall type of
> body fat could have evolved in a hot, dry climate.
>
Why! Is it unlikely because that conclusion would be uncomfortable or
is it unlikely because there is a more prominent, more highly evolved
example elsewhere?
> >>[Pauline] But as
> >> I've said before, the standard (energy-store) explanations are
> >> deficient (in my opinion), so an aquatic explanation is worth 'keeping
> >> on the table', so to speak.
> >
> >At least here in the States, those who frequent fast food joints and
> >shy away from beaches and swimming pools would perhaps bring
> >that view into some serious question! 8-)
>
> Yes, we have to be careful to exclude overfed modern humans from the
> equation, although it can be difficult to know exactly what fat a
> 'typical' pre-agricultural human might have had.
!kung, aborigines, Andaman Islanders, Amazonian & Orinocan tribes,
etc.
> >
> >So long as its "on the table" and not nailed to the wall like some sort
> >of holy icon, termites can always get to it! ;-) Im almost begining
> >to hear some shades of "reasonable doubt". . . . better watch out
> >or you might find it far less palatable than you once did, so to speak
> >of course! ;-)
>
> Sometimes I wonder if you read what I write, Bob. Do you remember the
> 'Plausible AAT ideas' post, where I laid out what I thought were the
> deficiencies in *all* the currently viable ideas for bipedalism,
> hairlessness and fat? That included the problems in the AAH scenarios.
> Of course there's reasonable doubt! Any degree of certainly leaves
> science behind, doesn't it?
I remember. Thats one of the only reasons I have for continuing these
discussions! A willingness to accept different views if the data supports
those different views is the separation between scientists and egotistical
"faith merchants".
> All I am saying is that *at the moment* I find the AAH proposals *more
> plausible* than any of the conventional alternatives. Mind you, that
> may say more about the current state of PA than about the AAH :-) I'm
> quite happy for you or anyone else to hold a different viewpoint, and
> I'm not trying to convince anyone. Quite the reverse - I would really
> like someone to convince *me* just why one of the conventional
> explanations for (say) bipedalism is more plausible than the wading
> idea.
And Im doing my absolute best to present arguements that force you to
look critically at the elements of the AAH, one at a time or separately, and
realize how far fetched some of them actually are. Why bother? Because
I think that you at least care about the merits. If Im wrong on that, let
me know and I can save a great deal of typing effort. 8-)
Regards
bk
Pauline M Ross
wrote:
>> [Pauline] Let me try again: all modern humans have a substantial amount of fat,
>> much more than our closest cousins. The numbers I have seen are 15-20%
>> for adult males and 20-25% for adult females, compared with 5% for a
>> chimp, but these numbers are anecdotal. Infants also have a lot of
>> fat, which begins to be laid down some 2 months before birth and lasts
>> for approximately 4 years. Adult females acquire their extra fat at
>> puberty, and a certain amount is required for fertility.
>
>OK. That first sentence is pretty positive. There are plenty of sources
>for the average body fat content for modern humans in an industrial
>society. There are very few (if any) equally comprehensive sources
>for data on the same parameter for modern humans in primitive societies.
>I've been able to find NO real references for the body fat content
>of chimps.
Like I said, it's anecdotal. There are plenty of comments by
primatologists and zoo workers that chimps generally have very little
fat. Beyond that I can't say, but 5% seems pretty reasonable to me.
By contrast, the lowest human body fat level I came across while
Googling was 8% in a male, in a query to a fitness site asking how to
reduce it even further (and the answer was, basically, forget it, it's
not possible). And this is an unusually low number for humans,
typically one would expect 15% or more for not overfed specimens.
So I think it's safe to say that humans (generally) have more body fat
than chimps (generally), but the actual numbers may be debateable, and
certainly pre-agricultural humans would have had less than modern
couch-potatoes, that goes without saying.
>This is very good! You have agreed to the connection between adult
>female body fat and reproduction! That tie-in is VITAL I think.
Well, you know, anything that appears at puberty and whose absence
absolutely stops fertility has got to be connected with reproduction,
don't you think? That's a no-brainer :-)
>"Survival advantage" is what its all about, right? Characteristics
>that provide some small, but still significant survival advantage
>tend to be acquired, right? And at least according to your above
>there is an undebatable indication that there IS a connection between
>human body fat and human reproduction.
>Could this be the connection? Why not?
It is absolutely clear that women with plenty of body fat have a
survival advantage over those who have very little - this is true
today, and must have been true for quite a long period of our history.
The question to be answered is *why* human ancestors needed a
substantial amount of body fat before they could reproduce, while
chimp ancestors did not. In fact, I don't know of any other primate
which needs to fatten up before it can breed. General good health is
usually sufficient.
>Might be hard to prove, one way or another, until some data is in
>on the chimps, but lets see if there is a "pattern". Lets separate
>those classes you laid out into two groups. The first group is adult
>females and infants, the second is adult males and pre-adolescent
>children.
OK, but bear in mind that adult females and infants acquire fat for
different reasons, since in adult females the fat is tied to
reproduction and infant fat clearly isn't. So I would say you need to
consider 3 separate groups.
>Males and adolescents need enough food energy of course
>to survive and perform whatever tasks they perform in the
>society, with perhaps a few more calories per pound for the
>adolescents physical growth, but its a pretty steady level.
>
>Females of the species on the other hand, usually have rather
>large and obvious "weight gain" with pregnancy, so long as
>adequate food is available, plus a "standing reserve" significantly
>higher than the average male. Infants ALSO have a rather
>larger fat reserve.
Yes.
>
>Could it be that in the mother's case, the reserves have evolved
>to support the very rapid physical growth that occurs both en utero
>where the mother is solely responsible for nutrition) and after birth
>(where for an extended period of time the mother is still responsible)
>in infants. For the infants, there is I suspect a period immediately
>after birth where the energy demands are very high and the digestive
>system is not yet fully "on line".
One could ask why the newborn's digestive system is *not* online,
which seems like a counter-productive development. You would think
that an infant whose system came online quicker than average would
have a distinct advantage, wouldn't you? But I digress.
It's very easy to say, well, there must be some very high energy
demands and that's what the fat reserves are for, but the question is
still why that should be so.
In fact there are (I think) 3 separate questions to be answered here:
1) Why do all humans have more body fat than other primates?
2) Why do human infants have such huge amounts of body fat at birth?
3) Why do adult human females need to have a substantial amount of
body fat before they can reproduce at all?
The standard answers are:
1) They don't.
2) To feed the growing brain.
3) To protect against periodic food shortages.
I've given my reasons for disputing all 3 standard answers in detail
recently, so I won't repeat them here, but then I don't think there
are *any* simple answers to this problem (including an aquatic one,
although that might be part of it).
You're welcome to have a go, but you have to explain just why humans
had (and have) such an unusual need for body fat, relative to other
primates. Saying they had greater energy needs just won't do it.
[Snip personal story, glad there was a happy ending!]
>
>Speaking of cellulose, noticed any signficant termite gnawing
>recently! ;-)
Not significantly, no, but keep at it, termite :-)
--
Pauline Ross
Bob Keeter
> On Sat, 15 May 2004 11:37:58 GMT, "Bob Keeter" <rke...@earthlink.net>
> wrote:
>
> >> [Pauline] Let me try again: all modern humans have a substantial amount
of fat,
> >> much more than our closest cousins. The numbers I have seen are 15-20%
> >> for adult males and 20-25% for adult females, compared with 5% for a
> >> chimp, but these numbers are anecdotal. Infants also have a lot of
> >> fat, which begins to be laid down some 2 months before birth and lasts
> >> for approximately 4 years. Adult females acquire their extra fat at
> >> puberty, and a certain amount is required for fertility.
> >
> >OK. That first sentence is pretty positive. There are plenty of sources
> >for the average body fat content for modern humans in an industrial
> >society. There are very few (if any) equally comprehensive sources
> >for data on the same parameter for modern humans in primitive societies.
> >I've been able to find NO real references for the body fat content
> >of chimps.
>
> Like I said, it's anecdotal. There are plenty of comments by
> primatologists and zoo workers that chimps generally have very little
> fat. Beyond that I can't say, but 5% seems pretty reasonable to me.
>
On what basis? Is 5% simply less than the 8% that you cite below
or is there a REASON for you to say that? If I were to say that
the body fat of chimps was 15%, why would that be wrong? 8-)
By the way, I DONT think that chimps have 15% body fat (except
maybe for the females), but. . . . tell me why my guestimate is worse
or "less meaningful" than yours? 8-)
> By contrast, the lowest human body fat level I came across while
> Googling was 8% in a male, in a query to a fitness site asking how to
> reduce it even further (and the answer was, basically, forget it, it's
> not possible). And this is an unusually low number for humans,
> typically one would expect 15% or more for not overfed specimens.
>
> So I think it's safe to say that humans (generally) have more body fat
> than chimps (generally), but the actual numbers may be debateable, and
> certainly pre-agricultural humans would have had less than modern
> couch-potatoes, that goes without saying.
I think so as well, BUT where is the evidence? Is it a 0.01% delta or
a 15% delta? this is the kind of thing that science thrives on, real
data is possible! 8-)
> >This is very good! You have agreed to the connection between adult
> >female body fat and reproduction! That tie-in is VITAL I think.
>
> Well, you know, anything that appears at puberty and whose absence
> absolutely stops fertility has got to be connected with reproduction,
> don't you think? That's a no-brainer :-)
>
Agreed! Its just that often in discussion like this (with others), such
flagrantly obvious inferences are simply denied. And yes, Id have
to say agreed on all points, implied as well as stated! 8-)
> >"Survival advantage" is what its all about, right? Characteristics
> >that provide some small, but still significant survival advantage
> >tend to be acquired, right? And at least according to your above
> >there is an undebatable indication that there IS a connection between
> >human body fat and human reproduction.
> >Could this be the connection? Why not?
>
> It is absolutely clear that women with plenty of body fat have a
> survival advantage over those who have very little - this is true
> today, and must have been true for quite a long period of our history.
>
POSSIBLY even more so in H/G societies?
> The question to be answered is *why* human ancestors needed a
> substantial amount of body fat before they could reproduce, while
> chimp ancestors did not. In fact, I don't know of any other primate
> which needs to fatten up before it can breed. General good health is
> usually sufficient.
OOOps, there you go again. Why do you suppose that chimp ancestors
do NOT require a certain amount of body fat? If you have supporting
data, great! Share it. If not, just toss in "I think" or "hyopthesize" or
perhaps some other scientifically supportable statement. But then
I have to ask, does "general good health" in modern humans not
specifically mean "adequate body fat" on the part of reproductive
females (excluding disease and "overtrained" female athletes)?
> >Might be hard to prove, one way or another, until some data is in
> >on the chimps, but lets see if there is a "pattern". Lets separate
> >those classes you laid out into two groups. The first group is adult
> >females and infants, the second is adult males and pre-adolescent
> >children.
>
> OK, but bear in mind that adult females and infants acquire fat for
> different reasons, since in adult females the fat is tied to
> reproduction and infant fat clearly isn't. So I would say you need to
> consider 3 separate groups.
Oh, I would say that females and infants have exactly the same need,
i.e. to nourish a young human! In one case, its en utero and afterwards
in the second its afterwards.
Snipapge. . .
> >Could it be that in the mother's case, the reserves have evolved
> >to support the very rapid physical growth that occurs both en utero
> >where the mother is solely responsible for nutrition) and after birth
> >(where for an extended period of time the mother is still responsible)
> >in infants. For the infants, there is I suspect a period immediately
> >after birth where the energy demands are very high and the digestive
> >system is not yet fully "on line".
>
> One could ask why the newborn's digestive system is *not* online,
> which seems like a counter-productive development. You would think
> that an infant whose system came online quicker than average would
> have a distinct advantage, wouldn't you? But I digress.
You are ABSOLUTELY correct. The problem is that during that
very early period there is a relatively HUGE nutritional requirement.
Look at the percentage weight gain over the first three years of life
versus any other period of time in a human lifespan. Look at the
elements of the body that grow most over that period. (maybe
look at the growth of elements of the body "above the shoulders?)
8-)
Look at the percentage weight gain of a foetus over its 9 month
sojurn.
In most cases, I dont think that its so much getting the digestive
system working, as getting it working to meet the energy requirements.
If you have the digestive tract of a newborn trying to run the
standard digestive products, even with the normally easily digested
and concentrated intake of mother's milk, the inefficiencies of normal
digestion could lead to a deficit. Now if you have a bunch of calories
stashed away on the baby there will be fewer "interruptions" in that
nutrient flow. Similarly, if the mother has a hefty storehouse to call
on, there is less likelyhood for short term interruptions if the HG
food supply suffers from day to day.
To me that sounds like a significant evolutionary advantage for each
and every generation. On the other hand, the supposed "ability" to
float better IF the baby were dropped in water, presuming that the
mother was wading or swimming, . . . . . . . . . lots of "if's" hidden in
there areent they? ;-) You count the "IF's" and make up your own
mind, remembering that each IF decreases the probabilies and we
are after the most probable answer (barring some proof that I just
dont know!. . . . . yet anyway! 8-0 )!
> It's very easy to say, well, there must be some very high energy
> demands and that's what the fat reserves are for, but the question is
> still why that should be so.
>
> In fact there are (I think) 3 separate questions to be answered here:
>
> 1) Why do all humans have more body fat than other primates?
Do they?
> 2) Why do human infants have such huge amounts of body fat at birth?
In order to survive!
> 3) Why do adult human females need to have a substantial amount of
> body fat before they can reproduce at all?
In order for their offspring to have a better chance to survive!
> The standard answers are:
> 1) They don't.
> 2) To feed the growing brain.
> 3) To protect against periodic food shortages.
Sorry, Guess I went back one level of abstraction. The first statement
is one that is very subject to factual corroboration or denial. What would
be the impact on the second and third if the first were disproved?
> I've given my reasons for disputing all 3 standard answers in detail
> recently, so I won't repeat them here, but then I don't think there
> are *any* simple answers to this problem (including an aquatic one,
> although that might be part of it).
The question is not what "might" be a part of anything, but rather what
is the most likely and logical conclusion (barring a yet to be discovered,
":hard proof" of course!).
> You're welcome to have a go, but you have to explain just why humans
> had (and have) such an unusual need for body fat, relative to other
> primates. Saying they had greater energy needs just won't do it.
UNLESS of course that proposition about body fat content turns out
to be contradicted by evidence or that human mothers and babies
DO have a higher nutritional requirement than other mammals! 8-)
Right?
> >Speaking of cellulose, noticed any signficant termite gnawing
> >recently! ;-)
>
> Not significantly, no, but keep at it, termite :-)
For the last 400 million years or so insects have never lacked
patience or persistence!
Regards
bk
Pauline M Ross
wrote:
>> >> [Pauline]The numbers I have seen are 15-20%
>> >> for adult males and 20-25% for adult females, compared with 5% for a
>> >> chimp, but these numbers are anecdotal.
[Snip]
>>[Pauline again] Like I said, it's anecdotal. There are plenty of comments by
>> primatologists and zoo workers that chimps generally have very little
>> fat. Beyond that I can't say, but 5% seems pretty reasonable to me.
>
>On what basis? Is 5% simply less than the 8% that you cite below
>or is there a REASON for you to say that? If I were to say that
>the body fat of chimps was 15%, why would that be wrong? 8-)
The only reason I mention the 5% number is because I have seen it
mentioned in connection with chimps. I have also seen quotes from zoo
workers that chimps have "no fat" but I don't give much credence to
that! It's somebody's guess, that's all (not mine). You could guess
15% if you want, I don't mind, but enough people who know both chimps
and humans have said that chimps have very little body fat, that I
think it is safe to say that they have *less* than humans (but the
actual numbers are debateable).
>>[Pauline] It is absolutely clear that women with plenty of body fat have a
>> survival advantage over those who have very little - this is true
>> today, and must have been true for quite a long period of our history.
>
>POSSIBLY even more so in H/G societies?
I don't know, why would it have been more so in h/g societies?
>> In fact, I don't know of any other primate
>> which needs to fatten up before it can breed. General good health is
>> usually sufficient.
>
>OOOps, there you go again. Why do you suppose that chimp ancestors
>do NOT require a certain amount of body fat? If you have supporting
>data, great! Share it. If not, just toss in "I think" or "hyopthesize" or
>perhaps some other scientifically supportable statement.
I'm sorry, I thought the words "I think that..." were understood. I'm
basing this on my opinion (derived from anecdotal evidence) that
modern chimps (and indeed all primates) have less body fat than modern
non-overfed humans, but as you know there is no hard data on wild
primate body fat (but your captive gorillas are interesting! more on
them later).
> But then
>I have to ask, does "general good health" in modern humans not
>specifically mean "adequate body fat" on the part of reproductive
>females (excluding disease and "overtrained" female athletes)?
By 'general good health' I mean not sick or malnourished (in the broad
sense). In humans, a degree of body fat would go along with that,
naturally.
>Oh, I would say that females and infants have exactly the same need,
>i.e. to nourish a young human! In one case, its en utero and afterwards
>in the second its afterwards.
Seems a bit belt-and-braces, though, doesn't it, to supply both mother
and infant with huge quantities of fat. There must be some major
potential crisis looming over them, wouldn't you say?
>You are ABSOLUTELY correct. The problem is that during that
>very early period there is a relatively HUGE nutritional requirement.
>Look at the percentage weight gain over the first three years of life
>versus any other period of time in a human lifespan. Look at the
>elements of the body that grow most over that period. (maybe
>look at the growth of elements of the body "above the shoulders?)
That's the standard answer, that's it's all to do with the brain, and
certainly the human brain uses a lot of energy. But where's the
evidence that lack of infant or maternal fat impacts in a significant
way on brain development? And if your captive gorillas have similar
levels of fat to humans, where does that leave the fat-for-brains
idea?
> Now if you have a bunch of calories
>stashed away on the baby there will be fewer "interruptions" in that
>nutrient flow. Similarly, if the mother has a hefty storehouse to call
>on, there is less likelyhood for short term interruptions if the HG
>food supply suffers from day to day.
So why would human h/g societies be more prone to day-to-day
interruptions to the food supply than any other primate?
>> [Pauline]In fact there are (I think) 3 separate questions to be answered here:
>> 1) Why do all humans have more body fat than other primates?
>[Bob]Do they?
>> [Pauline]2) Why do human infants have such huge amounts of body fat at birth?
>[Bob]In order to survive!
>> [Pauline]3) Why do adult human females need to have a substantial amount of
>> body fat before they can reproduce at all?
>[Bob]In order for their offspring to have a better chance to survive!
>> [Pauline]The standard answers are:
>> 1) They don't.
>> 2) To feed the growing brain.
>> 3) To protect against periodic food shortages.
>
>[Bob]Sorry, Guess I went back one level of abstraction. The first statement
>is one that is very subject to factual corroboration or denial. What would
>be the impact on the second and third if the first were disproved?
Good question. If humans (in general) have similar amounts of body fat
to other primates (in general), you still have fat human babies and
the human female's no-fat-no-babies deal to account for. You can only
eliminate the problem entirely if you say that humans accumulate fat
because we can (when we are well-fed), and that our babies and females
are the fattest primates because they are the best-fed primates.
Mind you, human babies are *extremely* fat - one of the 3 fattest
infants on earth, apparently (the other 2 being the harp seal and the
guinea pig). The harp seal infant is fat because it has a very short
lactation period, and the guinea pig because its mother's milk is
peculiarly unnourishing. Hard to see any parallels with humans, isn't
it?
So why do you think human babies are so fat? Are they just extremely
well-fed, or is there another reason for it?
>The question is not what "might" be a part of anything, but rather what
>is the most likely and logical conclusion (barring a yet to be discovered,
>":hard proof" of course!).
Well, logic has little to do with evolution, and even the most likely
explanation is not always the right one, even if we could agree on
what *is* the most likely :-)
>
>> [Pauline]You're welcome to have a go, but you have to explain just why humans
>> had (and have) such an unusual need for body fat, relative to other
>> primates. Saying they had greater energy needs just won't do it.
>
>[Bob] UNLESS of course that proposition about body fat content turns out
>to be contradicted by evidence or that human mothers and babies
>DO have a higher nutritional requirement than other mammals! 8-)
>Right?
Of course. Although you would still have to find a reason *why* they
have a greater nutritional requirement. Demonstrating it would be
interesting, but that alone doesn't tell you why.
Shall we talk about your gorillas now? That 44% figure is amazing, but
she was an obese female, and the other 3 had body fat levels around
half that. So (ignoring the obese female) captive gorillas have body
fat levels within modern human not-overfed ranges. Does that advance
the debate at all? Not sure...
Your figures for the Baka people (males 13.6%, females 24.3%) are more
interesting, but there isn't much information to go on. Are these
recent figures? Do they still have a traditional lifestyle? They seem
to have been severely impacted by agricultural incursion,
deforestation and so on, so it's not clear what these numbers actually
mean. I'm not deliberately nitpicking here, I just want to know
whether to put this data in the h/g pile or the agriculturalist (or
horticulturalist) pile. Any true h/g data would be welcome!
--
Pauline Ross
Paul Crowley
> 1) Why do all humans have more body fat than other primates?
I doubt if adult male humans need much
more than most other adult male primates.
Or that, if there a difference, it needs much
of an explanation. It _may_ be that humans
have, by-and-large, had it easier than other
species. Or , to put it another way, those
groups on top (those in control) -- who have
left nearly all the descendants -- have made
sure that they had good access to the
resources.
> 2) Why do human infants have such huge amounts of body fat at birth?
Easy -- insulation at night. Other primates
(a) are not altricial, and so are attached to
their mothers and can snuggle closer;
(b) they don't sleep on the ground at night;
(c) unlike human infants, they don't remain
incapable of sorting out their 'feeling-cold-
-at-night' problems for their first two or
three years.
> 3) Why do adult human females need to have a substantial amount of
> body fat before they can reproduce at all?
Easy -- their infants need all that fat. There
is no point in a woman getting pregnant if
the infant is almost certain to die within its
first few months -- from the cold.
Paul.
Bob Keeter
> On Sat, 15 May 2004 13:52:21 GMT, "Bob Keeter" <rke...@earthlink.net>
> wrote:
>
> >> >> [Pauline]The numbers I have seen are 15-20%
> >> >> for adult males and 20-25% for adult females, compared with 5% for a
> >> >> chimp, but these numbers are anecdotal.
> [Snip]
> >>[Pauline again] Like I said, it's anecdotal. There are plenty of
comments by
> >> primatologists and zoo workers that chimps generally have very little
> >> fat. Beyond that I can't say, but 5% seems pretty reasonable to me.
> >
> >On what basis? Is 5% simply less than the 8% that you cite below
> >or is there a REASON for you to say that? If I were to say that
> >the body fat of chimps was 15%, why would that be wrong? 8-)
>
> The only reason I mention the 5% number is because I have seen it
> mentioned in connection with chimps. I have also seen quotes from zoo
> workers that chimps have "no fat" but I don't give much credence to
> that! It's somebody's guess, that's all (not mine). You could guess
> 15% if you want, I don't mind, but enough people who know both chimps
> and humans have said that chimps have very little body fat, that I
> think it is safe to say that they have *less* than humans (but the
> actual numbers are debateable).
How's about some relatively non-debatable numbers. Did you read
the post and check the link to the gorilla post mortem?
:-) Still looking for chimp data, but from the looks of things, if offered
a nice stable diet in the confines of a zoo, gorillas seem to have just
about the same tendencies towards "the rotund" as modern HS. Maybe
we have more in common with our cousins than some would have thought,
particularly in terms of one particular discriminant.
> >>[Pauline] It is absolutely clear that women with plenty of body fat have
a
> >> survival advantage over those who have very little - this is true
> >> today, and must have been true for quite a long period of our history.
> >
> >POSSIBLY even more so in H/G societies?
>
> I don't know, why would it have been more so in h/g societies?
In a H/G group the food supply would be very much a day-to-day thing
depending on the luck of the hunters and the persistence of the gatherers.
Some days you eat very well indeed, some days not quite so lucky. An
adult with only "energy needs", probably can get by fairly easily. A baby
or a nursing mother on the other hand, needs to damp out some of those
dips. But then isnt it usually the babies and pregnant women who feel the
force of starvation FIRST in primitive societies that run up on hard times.
Or for that matter even some not so primitive societies when the food
supply runs short.
> >> In fact, I don't know of any other primate
> >> which needs to fatten up before it can breed. General good health is
> >> usually sufficient.
> >
> >OOOps, there you go again. Why do you suppose that chimp ancestors
> >do NOT require a certain amount of body fat? If you have supporting
> >data, great! Share it. If not, just toss in "I think" or "hyopthesize"
or
> >perhaps some other scientifically supportable statement.
>
> I'm sorry, I thought the words "I think that..." were understood. I'm
> basing this on my opinion (derived from anecdotal evidence) that
> modern chimps (and indeed all primates) have less body fat than modern
> non-overfed humans, but as you know there is no hard data on wild
> primate body fat (but your captive gorillas are interesting! more on
> them later).
Good, you saw the article!
Still looking for something close to a "wild ape" data set. Havent given
up by any means (even found a few new "search string" possibilities in the
gorilla data. I will be waiting with great anticipation when you cover the
44% body fat MEASURED in the rather overfed female gorilla. 8-))
Just a thought though. . . . if the "above average" body fat of humans, and
now it would seem gorillas, is there any reason to imagine that these
conditions were "caused" by different environmental stimuli in so closely
related species? Perhaps they were both inspired by the same input,
but then if "aquatic" in nature, why did that stimulus not also cause
hairlessness in gorillas? (And remember, hairlessness is one of those
"extreme" aquatic adaptations found in ALL fully aquatic mammals, and
found in none (or virtually none) of the semi-aquatics! (I'll even concede
you the very shakey reference to the pigmy hippo!)
Wouldnt "comparitive analysis", or whatever term it is that gets bantered
around in favor of the AAH so often, demand that we consider a common
trait, between two closely related and at least historically co-habitating
species to be caused by the same stimulus? Whales are hairless and live
in water, humans are hairless and must have at least an association with
the water. Well fed humans have significant body fat, whales have
signiificant
body fat, well fed gorillas have significant body fat, therefore gorillas
are
also descendents of an aquatic past? 8-) Sorry, I do get carried away.
8-))
> > But then
> >I have to ask, does "general good health" in modern humans not
> >specifically mean "adequate body fat" on the part of reproductive
> >females (excluding disease and "overtrained" female athletes)?
>
> By 'general good health' I mean not sick or malnourished (in the broad
> sense). In humans, a degree of body fat would go along with that,
> naturally.
8-) Good!
> >Oh, I would say that females and infants have exactly the same need,
> >i.e. to nourish a young human! In one case, its en utero and afterwards
> >in the second its afterwards.
>
> Seems a bit belt-and-braces, though, doesn't it, to supply both mother
> and infant with huge quantities of fat. There must be some major
> potential crisis looming over them, wouldn't you say?
Nope. Not at all. Lets say that a relatively fat mother increases the
probability
of baby's survival by 1%. A fat baby at birth might add another 1% to that
and
suddenly you have a 2% tilt in favor of the fat mother/fat baby vs the
famine-thin
mother and emaciated baby. A measly 2% edge would be huge in an
evolutionary
timeframe. those numbers are total speculation, you pick the numbers. So
long
as a fat mother is the slightest advantage to primative apith (or earlier)
reproduction
and a fat baby has a better chance of surviving the dry season, the two
"advantages"
are totally complementary and non-contradictory, maybe even synergistic!
8-)
> >You are ABSOLUTELY correct. The problem is that during that
> >very early period there is a relatively HUGE nutritional requirement.
> >Look at the percentage weight gain over the first three years of life
> >versus any other period of time in a human lifespan. Look at the
> >elements of the body that grow most over that period. (maybe
> >look at the growth of elements of the body "above the shoulders?)
>
> That's the standard answer, that's it's all to do with the brain, and
> certainly the human brain uses a lot of energy. But where's the
> evidence that lack of infant or maternal fat impacts in a significant
> way on brain development? And if your captive gorillas have similar
> levels of fat to humans, where does that leave the fat-for-brains
> idea?
Pauline, you must have not been paying much attention to what you
were typing, or just not thinking about what was said. Thats OK.
Go to google. Type in /malnutrition "mental retardation"/. I get about
12,500 references. I wont bother to cite but just a couple from the
top of the list.. . . . .
http://encarta.msn.com/encyclopedia_761552226/Mental_Retardation.html
"Malnutrition during pregnancy is a common cause of mental retardation in
developing countries, where many women do not consume adequate amounts of
protein and other necessary nutrients."
Now if you compare the brain size to body mass for humans and gorillas, you
will
see that humans are head and sholders above the big apes. On the other hand
if you compare the brain mass/body mass of gorillas with cats, dogs,
gazelles, or other
mammals, the gorilla is a veritible egg head Perhaps the need for pre-natal
body fat is greater in humans than in gorillas, but at least one study shows
that
the capacity is there in both!.
> > Now if you have a bunch of calories
> >stashed away on the baby there will be fewer "interruptions" in that
> >nutrient flow. Similarly, if the mother has a hefty storehouse to call
> >on, there is less likelyhood for short term interruptions if the HG
> >food supply suffers from day to day.
>
> So why would human h/g societies be more prone to day-to-day
> interruptions to the food supply than any other primate?
They would NOT be, except potentially as a matter of degree. All higher
primates
tend to have big brains on the mammalian scale.
Snippage. . .
> >[Bob]Sorry, Guess I went back one level of abstraction. The first
statement
> >is one that is very subject to factual corroboration or denial. What
would
> >be the impact on the second and third if the first were disproved?
>
> Good question. If humans (in general) have similar amounts of body fat
> to other primates (in general), you still have fat human babies and
> the human female's no-fat-no-babies deal to account for. You can only
> eliminate the problem entirely if you say that humans accumulate fat
> because we can (when we are well-fed), and that our babies and females
> are the fattest primates because they are the best-fed primates.
ANd the best way to make that point would be to autopsy some equally
well fed primates and determine their body fat, right? 8-)
> Mind you, human babies are *extremely* fat - one of the 3 fattest
> infants on earth, apparently (the other 2 being the harp seal and the
> guinea pig). The harp seal infant is fat because it has a very short
> lactation period, and the guinea pig because its mother's milk is
> peculiarly unnourishing. Hard to see any parallels with humans, isn't
> it?
Unless humans have some greater need for nourishment during the
early stages. . . . . 8-) Here you have two very divergent "reasons" for
baby fat, why should humans' baby fat be similar to either of these?
You cant logically and supportably "pattern match" to the absence of a
pattern!
But you see, baby fat would be very much a non sequiteur in the AAH
arguement
IF the same fat in adults was demonstrated to simply be energy caching,
PARTICULARLY if that energy cacheing occurs in other great apes.
Wouldnt make a great deal of sense for a human infant to be the only member
of the primates (including adult humans) to be adapted to a watery
environment
when the same "adaptation" in all other primates would appear to have a
very different purpose. . . . . unless of course you were hanging on to a
dead
duck point of arguementation and just trying to find an angle that would
allow skirting that issue. Hang on to the points worth haggling, concede
the lost causes. 8-) At least concede when it gets to be too embarassing
to hang on!
> So why do you think human babies are so fat? Are they just extremely
> well-fed, or is there another reason for it?
There is absolutely another reason, and its the reason that probably 99% of
the medical, anthropological and paleoanthropological world suggests. But
then that is the world that is "out to get" the AAH, right? 8-)
> >The question is not what "might" be a part of anything, but rather what
> >is the most likely and logical conclusion (barring a yet to be
discovered,
> >":hard proof" of course!).
>
> Well, logic has little to do with evolution, and even the most likely
> explanation is not always the right one, even if we could agree on
> what *is* the most likely :-)
But logic is ALL that we have to define some of these factors in
evolutionary
process that have long since done their work and disappeared. You pick
the most likely answer, and until someone provides a more logical and more
likely answer, supported by evidence that contradicts the previous paradigm.
Sort of like an intellectual "king of the hill" game where everyone can
"cheat"
by denying the most compelling logic or the undeniable evidence, if they
have
the kind of personality that demands that "they be right" in all things no
matter
what the facts. (Know a few that fit that mold?).
> >> [Pauline]You're welcome to have a go, but you have to explain just why
humans
> >> had (and have) such an unusual need for body fat, relative to other
> >> primates. Saying they had greater energy needs just won't do it.
> >
> >[Bob] UNLESS of course that proposition about body fat content turns out
> >to be contradicted by evidence or that human mothers and babies
> >DO have a higher nutritional requirement than other mammals! 8-)
> >Right?
>
> Of course. Although you would still have to find a reason *why* they
> have a greater nutritional requirement. Demonstrating it would be
> interesting, but that alone doesn't tell you why.
Demonstrating the need and demonstrating an understanding of that need
are two very different things. For millions of years evolutionary pressures
pushed us towards mental development, yet only in the last few hundered
years have we even recognized the process of evolution. If human babies
HAVE a need for better, more consistent nutrition than most mammalian
babies, that will become an evolutionary "forcing function", no matter what
that
underlying cause for the need might be.
> Shall we talk about your gorillas now? That 44% figure is amazing, but
> she was an obese female, and the other 3 had body fat levels around
> half that. So (ignoring the obese female) captive gorillas have body
> fat levels within modern human not-overfed ranges. Does that advance
> the debate at all? Not sure...
>
I would suggest that this demonstrates that at least one zookeeper did
not have the health of his charges as well in focus as the others and
allowed
one female to become obese. The others were kept to a more "natural"
level, perhaps emulated by adequately, but not overly fed humans! 8-)
Need more proof that humans and gorillas are "cousins"?
ONLY if you still suggest that human "body fat" is a distinguishing factor
between humans and other higher apes. Only if you still insist that human
body fat is an indicator of an "aquatic existence" not shared by humans
and gorillas!
You tell me if its "advancing" the debate or not. Id settle for just
letting
the body fat issue disappear as a point of contention since it seems to
predate
the human/gorilla/orangutan LCAs. Right?
> Your figures for the Baka people (males 13.6%, females 24.3%) are more
> interesting, but there isn't much information to go on. Are these
> recent figures? Do they still have a traditional lifestyle? They seem
> to have been severely impacted by agricultural incursion,
> deforestation and so on, so it's not clear what these numbers actually
> mean. I'm not deliberately nitpicking here, I just want to know
> whether to put this data in the h/g pile or the agriculturalist (or
> horticulturalist) pile. Any true h/g data would be welcome!
I THINK that the Baka are probably closer to the HG pile than the
horticulturalists pile, but would not even want to suggest that they
had no connection with the agriculturalists or technological societies. I
would say that they did not frequent McDonalds often.
Regards
bk
firstjois
>> "Pauline M Ross" <pmr...@ross-software.co.uk> wrote in message
>> news:e1nba0tid2mu4761r...@4ax.com...
>>
>>> All I am saying is that *at the moment* I find the AAH proposals
>>> *more plausible* than any of the conventional alternatives. Mind
>>> you, that may say more about the current state of PA than about the
>>> AAH :-) I'm quite happy for you or anyone else to hold a different
>>> viewpoint, and I'm not trying to convince anyone. Quite the reverse
>>> - I would really like someone to convince *me* just why one of the
>>> conventional explanations for (say) bipedalism is more plausible
>>> than the wading idea.
>>
[snip]
I think I've seen that exact statement before, Pauline, are you mastering
the marco? Oops, macro? It's turning out to be a long long "at the
moment."
Jois
--
The only wading adaptation any animal
needs is the willingness to get your feet wet.
That's it.
Rick Wagler
021003
Pauline M Ross
wrote:
>> [Pauline]But where's the
>> evidence that lack of infant or maternal fat impacts in a significant
>> way on brain development? And if your captive gorillas have similar
>> levels of fat to humans, where does that leave the fat-for-brains
>> idea?
>
>Pauline, you must have not been paying much attention to what you
>were typing, or just not thinking about what was said. Thats OK.
>Go to google. Type in /malnutrition "mental retardation"/. I get about
>12,500 references. I wont bother to cite but just a couple from the
>top of the list.. . . . .
>http://encarta.msn.com/encyclopedia_761552226/Mental_Retardation.html
>"Malnutrition during pregnancy is a common cause of mental retardation in
>developing countries, where many women do not consume adequate amounts of
>protein and other necessary nutrients."
I feel like I'm in Groundhog Day... this has been discussed so many
times already... But one more time, briefly:
The whole point of the fat-for-brains idea is that it *protects* the
baby against mental damage resulting from malnutrition or other
interruptions to the food supply. So you should only see measurable
brain damage if the baby has very little fat to start with, or if the
interruption is severe enough to deplete its fat.
But what research actually shows is that *any* interruption produces
subtle but measurable effects (so no protection from the fat), but
even quite severe episodes of malnutrition do not necessarily result
in permanent, measurable brain damage if the nutritional deficiencies
are corrected (so the brain isn't that functionally vulnerable
anyway).
[Huge snip]
>ONLY if you still suggest that human "body fat" is a distinguishing factor
>between humans and other higher apes. Only if you still insist that human
>body fat is an indicator of an "aquatic existence" not shared by humans
>and gorillas!
Well, until we have accurate figures, I shall continue to take the
word of primatologists and zookeepers that chimps have very little
fat. But I've never insisted that human body fat is an indicator of an
aquatic existence, only that subcutaneous fat is common in aquatic
mammals and very rare in terrestrial ones. As for gorillas *not*
having had an 'aquatic' existence, there is some evidence that all the
apes may have been more aquatic than they are now, but that is highly
speculative.
>I THINK that the Baka are probably closer to the HG pile than the
>horticulturalists pile, but would not even want to suggest that they
>had no connection with the agriculturalists or technological societies. I
>would say that they did not frequent McDonalds often.
I'm sure that's true, but what frequently happens when h/g societies
are first exposed to agricultural or technological societies is that
they suddenly add many of the worst food elements into their diet
(like alcohol, and refined grains and sugars) and acquire a lot of
body fat overnight. So we need to be cautious about these numbers.
Now some bad news (or is it good news? - you decide). Unfortunately,
real life (a messy upcoming house-move) is interfering with my ability
to respond to your lengthy posts in the detail I would like, so I'm
going to bail out of sap for the moment. I hope we can continue this
in the future.
In the meantime, I wish you well, and leave you to nibble away
elsewhere, little termite :-)
--
Pauline Ross
Jason Eshleman
Top endurance athletes can have body fat down as low as 4% in extreme
cases. 6 or 7% is uncommon, but not unheard of.
While we do seem, on average to carry more fat than a wild chimp there are
a number of things exceptionally different about us and chimps. The focus
on swimming, something that as the animal kingdom goes, we're not very
good at seems silly. The areas where we undeniably differ from chimps
would seem more reasonable thing to look at. We've got bigger, expensive
to feed brains and we're much better distance travelers than chimps. In
this first area, we're unparalled. The EQ of a human is roughly 3 times
that of a chimp.
In this second area, we're also damn near the top of the animal kingdom.
As slow a top speed as bipedalism gives us (low effectiveness), over the
long haul we're quite efficient. I'd be curious to see how our fat stores
compare with non-seasonal stores in other "endurance" animals like horses.
Of note, I've found that average body fat in fit horses was 7.4% for males
and 9.9% for females.
Jason Eshleman
>On Sat, 15 May 2004 11:37:58 GMT, "Bob Keeter" <rke...@earthlink.net>
>wrote:
>
>>> [Pauline] Let me try again: all modern humans have a substantial amount of fat,
>>> much more than our closest cousins. The numbers I have seen are 15-20%
>>> for adult males and 20-25% for adult females, compared with 5% for a
>>> chimp, but these numbers are anecdotal. Infants also have a lot of
>>> fat, which begins to be laid down some 2 months before birth and lasts
>>> for approximately 4 years. Adult females acquire their extra fat at
>>> puberty, and a certain amount is required for fertility.
>>
>>OK. That first sentence is pretty positive. There are plenty of sources
>>for the average body fat content for modern humans in an industrial
>>society. There are very few (if any) equally comprehensive sources
>>for data on the same parameter for modern humans in primitive societies.
>>I've been able to find NO real references for the body fat content
>>of chimps.
>
>Like I said, it's anecdotal. There are plenty of comments by
>primatologists and zoo workers that chimps generally have very little
>fat. Beyond that I can't say, but 5% seems pretty reasonable to me.
>
>By contrast, the lowest human body fat level I came across while
>Googling was 8% in a male, in a query to a fitness site asking how to
>reduce it even further (and the answer was, basically, forget it, it's
>not possible). And this is an unusually low number for humans,
>typically one would expect 15% or more for not overfed specimens.
You should refine your google terms. I had no problem finding reports of
the range for males dropping down to as low as 5%. While this is low, and
it's probably true that in general modern humans tend to store more fat
than modern apes when neither are overly sendentary nor overly fed, the
comparisons look more realistic when you start to compare apples and
apples.
Paul Crowley
news:c884oa$s9j$1...@woodrow.ucdavis.edu...
> While we do seem, on average to carry more fat than a wild chimp there are
> a number of things exceptionally different about us and chimps. The focus
> on swimming, something that as the animal kingdom goes, we're not very
> good at seems silly. The areas where we undeniably differ from chimps
> would seem more reasonable thing to look at.
Except that there are an enormous number
of differences -- morphological and
behavioural; and we are unsure about the
nature, let alone the origin or many of them.
> We've got bigger, expensive
> to feed brains and we're much better distance travelers than chimps. In
> this first area, we're unparalled. The EQ of a human is roughly 3 times
> that of a chimp.
>
> In this second area, we're also damn near the top of the animal kingdom.
Is there real evidence for this? Or is it
just all wishful thinking? And does it
assume that the human athlete has a
plentiful supply of warter, and/or
portable water bottles?
> As slow a top speed as bipedalism gives us (low effectiveness), over the
> long haul we're quite efficient. I'd be curious to see how our fat stores
> compare with non-seasonal stores in other "endurance" animals like horses.
It is, in any case, a ridiculous argument.
As ever you are making the standard PA
assumption that the species consists
solely of adult males.
Essentially we are trying to explain the
huge amounts of _female_ and _infant_
body fat. Females and infants do not
go on extended runs in any known H/G
society.
Paul.
Paul.
Jason Eshleman
>"Jason Eshleman" <j...@vidi.ucdavis.edu> wrote in message
>> We've got bigger, expensive
>> to feed brains and we're much better distance travelers than chimps. In
>> this first area, we're unparalled. The EQ of a human is roughly 3 times
>> that of a chimp.
>>
>> In this second area, we're also damn near the top of the animal kingdom.
>Is there real evidence for this? Or is it
>just all wishful thinking? And does it
>assume that the human athlete has a
>plentiful supply of warter, and/or
>portable water bottles?
There is evidence for this. Humans have a greater ability to travel long
distances relatively uninterrupted than most terrestrial creatures. We do
require access to water in doing so. Most animals require access to
water.
>> As slow a top speed as bipedalism gives us (low effectiveness), over the
>> long haul we're quite efficient. I'd be curious to see how our fat stores
>> compare with non-seasonal stores in other "endurance" animals like horses.
>
>It is, in any case, a ridiculous argument.
>As ever you are making the standard PA
>assumption that the species consists
>solely of adult males.
'Scuse me? I realize that you're a broken record and seem unable to do
much more than parrot that line. Care to explain how it is that I'm
making this assumption? I'm looking back at what I read. Can't quite
figure out where it is, unless of course you just made it up.
>Essentially we are trying to explain the
>huge amounts of _female_ and _infant_
>body fat. Females and infants do not
>go on extended runs in any known H/G
>society.
"We" are not trying to explain anything. "You" are simply parroting a
tired line that makes it look like you have a personal vendetta against
a professor who gave you poor marks, or perhaps the tough anthropologists
used to beat you up as a kid.
Bob Keeter
> >http://encarta.msn.com/encyclopedia_761552226/Mental_Retardation.html
> >"Malnutrition during pregnancy is a common cause of mental retardation in
> >developing countries, where many women do not consume adequate amounts of
> >protein and other necessary nutrients."
>
> I feel like I'm in Groundhog Day... this has been discussed so many
> times already... But one more time, briefly:
>
> The whole point of the fat-for-brains idea is that it *protects* the
> baby against mental damage resulting from malnutrition or other
> interruptions to the food supply. So you should only see measurable
> brain damage if the baby has very little fat to start with, or if the
> interruption is severe enough to deplete its fat.
So having a healthy supply of body fat "helps" in the survival and
procreation of a creature with a bigger, more functional brain?
Is that not pretty close to the definition of an evolutionary advantage
for a creature that must depend on its wits, and not its claws, teeth, or
simple bulk for survival? IOW, I thin that this is exactly what I was
trying to say! Sorry if it did not come out that way. Since that
body fat does in fact "protect" the baby during the early stages of
life, do I need other justification for it having evolved? Parsimoniously,
now, please! 8-)
> But what research actually shows is that *any* interruption produces
> subtle but measurable effects (so no protection from the fat), but
> even quite severe episodes of malnutrition do not necessarily result
> in permanent, measurable brain damage if the nutritional deficiencies
> are corrected (so the brain isn't that functionally vulnerable
> anyway).
So the issue is does the retardation caused by malnutrition reverse itself
later in life with better food? My personal guess is that there might be
some recovery, after all people with severe brain injuries SOMETIMES
regain abilities with time, but usually, I think that brain damage is
generally accepted as non-recoverable. Furthermore, it would be a
real reach to imagine that the growth lost during the formative years
Found several references to improvement so long as the better
diet kicked in before the age of three. Isnt that just about the
place where the "baby fat" is pretty much gone?
Also found:
http://www.healthpro.org.uk/facts/nutrit2.htm#2
> [Huge snip]
> >ONLY if you still suggest that human "body fat" is a distinguishing
factor
> >between humans and other higher apes. Only if you still insist that
human
> >body fat is an indicator of an "aquatic existence" not shared by humans
> >and gorillas!
>
> Well, until we have accurate figures, I shall continue to take the
> word of primatologists and zookeepers that chimps have very little
> fat. But I've never insisted that human body fat is an indicator of an
> aquatic existence, only that subcutaneous fat is common in aquatic
> mammals and very rare in terrestrial ones. As for gorillas *not*
> having had an 'aquatic' existence, there is some evidence that all the
> apes may have been more aquatic than they are now, but that is highly
> speculative.
Could I suggest that you must include "common in aquatic mammals and
at least THREE large primates". So all apes are now "aquatic connected"?
Not sure if thats good or bad, but certainly would eliminate SC fat (and
the water association) as a discriminator between Homo and the other
primates now wouldnt it? If it does that, i.e. if we assume all apes
to have had an aquatic past, it blows the hairlessness issue out of the
water!
(Sorry for the pun, but. . . . . 8-) ) Cant have hairy aquatic apes if the
water environment forced us to exebitionism! 8-)
> >I THINK that the Baka are probably closer to the HG pile than the
> >horticulturalists pile, but would not even want to suggest that they
> >had no connection with the agriculturalists or technological societies. I
> >would say that they did not frequent McDonalds often.
>
> I'm sure that's true, but what frequently happens when h/g societies
> are first exposed to agricultural or technological societies is that
> they suddenly add many of the worst food elements into their diet
> (like alcohol, and refined grains and sugars) and acquire a lot of
> body fat overnight. So we need to be cautious about these numbers.
8-) But is there ANY prima facie reason to discount those numbers? 15%
body fat was, iirc your own number for a reasonable value for body fat
in "non-overfed" humans. I found an example that merely confirmed it!
On the other hand, the gorilla numbers I would definitly put on a par
with modern humans in an industrial society (very few captive gorillas
in economically challenged human societies), well fed with a lot of
leisure time. Those numbers might just not be all that "out of order"
when compared with modern humans, even the obesely fat female!
Guess I would have to say that I should not be greatly surprised
if when (and I do mean when!) I find similar data on chimps that
it would match up with the human, gorilla, and orangutan information.
We are after all rather closely related. Similar "inputs" on basic
things like food and I would expect very similar responses! Wouldnt
you?
> Now some bad news (or is it good news? - you decide). Unfortunately,
> real life (a messy upcoming house-move) is interfering with my ability
> to respond to your lengthy posts in the detail I would like, so I'm
> going to bail out of sap for the moment. I hope we can continue this
> in the future.
I'll still be here, and I do have a pretty good memory still. (Must be
a good fat layer at birth or else a marvelous recovery to my current
state of relative immunity! ;-) )
Finish your move, think about what we have discussed, CRITICALLY
review those "more likely" assessments of yours, and let us know when
you are ready to resume the battle! ;-) AND on what terms you see
those assessments! 8-))
> In the meantime, I wish you well, and leave you to nibble away
> elsewhere, little termite :-)
>
I only do pernicious theories so your new house is safe! 8-)
Regards
bk
firstjois
>> On Sat, 15 May 2004 13:52:21 GMT, "Bob Keeter"
>> <rke...@earthlink.net> wrote:
>>
>> That's the standard answer, that's it's all to do with the brain, and
>> certainly the human brain uses a lot of energy. But where's the
>> evidence that lack of infant or maternal fat impacts in a significant
>> way on brain development? And if your captive gorillas have similar
>> levels of fat to humans, where does that leave the fat-for-brains
>> idea?
>>
[snip]
>> Pauline Ross
That looks like oranges and plums!
--
Hypothesis of an Aquatic Human Ancestor (HAHA),
Lorenzo 2003
Paul Crowley
news:c88vvb$jcq$1...@woodrow.ucdavis.edu...
> >> We've got bigger, expensive
> >> to feed brains and we're much better distance travelers than chimps. In
> >> this first area, we're unparalled. The EQ of a human is roughly 3 times
> >> that of a chimp.
> >>
> >> In this second area, we're also damn near the top of the animal kingdom.
>
> >Is there real evidence for this? Or is it
> >just all wishful thinking? And does it
> >assume that the human athlete has a
> >plentiful supply of warter, and/or
> >portable water bottles?
>
> There is evidence for this. Humans have a greater ability to travel long
> distances relatively uninterrupted than most terrestrial creatures.
If we were talking about any other species
(i.e. not our own) and if you were not
reciting an ancient hackneyed old tale,
you would remark on the extreme inability
of the bulk of the species to travel any
distance at all. Hominid mothers with
infants (and without blankets or other
carrying devices) and with small children
could only have made extremely slow
progress -- far slower than all other
terrestrial species. The distances they
were capable of travelling would have
been tiny.
> We do require access to water in doing so.
> Most animals require access to water.
So -- even for adult males (whom you assume
to be the whole species) -- that's the end of
this little story. Hominids in Africa would
not travel long distances, except when they
carefully planned their journeys and went
from one water hole to the next.
> >> As slow a top speed as bipedalism gives us (low effectiveness), over the
> >> long haul we're quite efficient. I'd be curious to see how our fat stores
> >> compare with non-seasonal stores in other "endurance" animals like horses.
> >
> >It is, in any case, a ridiculous argument.
> >As ever you are making the standard PA
> >assumption that the species consists
> >solely of adult males.
>
> 'Scuse me? I realize that you're a broken record and seem unable to do
> much more than parrot that line. Care to explain how it is that I'm
> making this assumption? I'm looking back at what I read. Can't quite
> figure out where it is, unless of course you just made it up.
Are you really claiming that females and
infants in H/G societies go on extended
runs and need fat for endurance?
> >Essentially we are trying to explain the
> >huge amounts of _female_ and _infant_
> >body fat. Females and infants do not
> >go on extended runs in any known H/G
> >society.
>
> "We" are not trying to explain anything.
I can see that you are not trying to explain
anything at all. You are locked into some
Victorian conception of the world -- as is the
whole of PA -- which is why we never get an
explanation of anything in this 'science'.
Are you denying that the fat levels in human
males can go down to something close to the
typical levels for other primates? Whereas
the fat levels in human females must -- if
they are to function normally as females and
regularly get pregnant -- be at a level FAR
higher than that found in other primate
females?
Paul.
Nick Maclaren
In article <c88vvb$jcq$1...@woodrow.ucdavis.edu>,
j...@veni.ucdavis.edu (Jason Eshleman) writes:
|> Paul Crowley <slkwuoiut...@slkjlskjoioue.com> wrote:
|>
|> >> We've got bigger, expensive
|> >> to feed brains and we're much better distance travelers than chimps. In
|> >> this first area, we're unparalled. The EQ of a human is roughly 3 times
|> >> that of a chimp.
|> >>
|> >> In this second area, we're also damn near the top of the animal kingdom.
|>
|> >Is there real evidence for this? Or is it
|> >just all wishful thinking? And does it
|> >assume that the human athlete has a
|> >plentiful supply of warter, and/or
|> >portable water bottles?
|>
|> There is evidence for this. Humans have a greater ability to travel long
|> distances relatively uninterrupted than most terrestrial creatures. We do
|> require access to water in doing so. Most animals require access to
|> water.
There is evidence, but it is not as simple as that. While we are
among the best long-distance travellers - we are nowhere near as
high if you rank by distance between drinks. We are, however,
quite high enough to count as being savanna-adapted in this
respect.
But that is NOW. The hard question is how we got here from there.
All plausible transitions between a chimpanzee-like ape and an
early bipedal human involve a phase where the animal would have
been even worse than a chimpanzee at long-distance travel. That
change could NOT have happened on the savanna. And, unless there
was a survival advantage to developing efficient bipedal locomotion,
Darwinism implies that we should have reverted. We didn't.
There is a missing explanation.
Regards,
Nick Maclaren.
Jim McGinn
> All plausible transitions between a chimpanzee-like ape and an
> early bipedal human involve a phase where the animal would have
> been even worse than a chimpanzee at long-distance travel. That
> change could NOT have happened on the savanna.
They must have had some strategy to deal with the dry season.
What would you suggest?
But, I agree, walking efficiency is, at best, maybe a bit less
ridiculous than Aquatic Ape. Just a bit.
Jim
Jason Eshleman
This is incorrect. Not all plausible transitions rely on a local maximum
in the transition. I realize that it's a data poor area currently, but
there *(IS* evidence that a bipedal gait is no less *efficient* than a
quadrupedal one for chimps. If this really is the case (again, it's data
poor, but that is what the limited data indicates) then it isn't
necessarily so that a shift would be less efficient. The assertion that
knucklewalking would have been a local maximum isn't necessarily so.
Bob Keeter
> Nick Maclaren <nm...@cus.cam.ac.uk> wrote:
Snippage. . . . .
> >
> >All plausible transitions between a chimpanzee-like ape and an
> >early bipedal human involve a phase where the animal would have
> >been even worse than a chimpanzee at long-distance travel. That
> >change could NOT have happened on the savanna. And, unless there
> >was a survival advantage to developing efficient bipedal locomotion,
> >Darwinism implies that we should have reverted. We didn't.
>
> This is incorrect. Not all plausible transitions rely on a local maximum
> in the transition. I realize that it's a data poor area currently, but
> there *(IS* evidence that a bipedal gait is no less *efficient* than a
> quadrupedal one for chimps. If this really is the case (again, it's data
> poor, but that is what the limited data indicates) then it isn't
> necessarily so that a shift would be less efficient. The assertion that
> knucklewalking would have been a local maximum isn't necessarily so.
>
Another thing to consider guys. . . . . . Mechanical efficiency is very
different
from simple fatigue. An upright bipedal gait has many things in its favor
in
terms of mechanical efficiency (and the energy required). On the other
hand,
if the musculature (and bone structure) is just not made for that mode (as
is to a degree the case with the chimp) it can become very fatiguing even
with
the lesser energy expenditure.
For example, "running" 100 yrds quadrupedally by a chimp might expend twice
the energy, but because that energy deficit is "shared" amongst four limbs,
the
chimp is less fatigued than trying to do the same bipedally.
Regards
bk
Nick Maclaren
In article <qsdqc.16871$KE6....@newsread3.news.atl.earthlink.net>,
Yes. Jason Eshleman ignores two important facts:
Firstly, in order for practical survival on the savanna, we are
fairly close to the MINIMUM efficiency for long-distance travel.
Chimpanzees are WAY below it, and a population would die out in
short order. Observed figures for their movements are about
2-6 km a day. For survival on the savanna, 15-20 is needed.
The second is that the 'transition' is a MAJOR change, and must
have involved many mutations over hundreds of generations. The
probabilities are such that it could happen ONLY if there is a
definite survival advantage towards bipedalism at almost all
stages and there is ALMOST NEVER a survival advantage for
reversion.
Regards,
Nick Maclaren.
Paul Crowley
>
> In article <qsdqc.16871$KE6....@newsread3.news.atl.earthlink.net>,
> "Bob Keeter" <rke...@earthlink.net> writes:
> |> Another thing to consider guys. . . . . . Mechanical efficiency is
> |> very different from simple fatigue. An upright bipedal gait has
> |> many things in its favor in terms of mechanical efficiency (and
> |> the energy required). On the other hand, if the musculature
> |> (and bone structure) is just not made for that mode (as is to a
> |> degree the case with the chimp) it can become very fatiguing
> |> even with the lesser energy expenditure.
> |>
> |> For example, "running" 100 yrds quadrupedally by a chimp might
> |> expend twice the energy, but because that energy deficit is
> |> "shared" amongst four limbs, the chimp is less fatigued than
> |> trying to do the same bipedally.
>
> Yes. Jason Eshleman ignores two important facts:
He (and the rest of you) ignore other important facts
in that you are looking solely at the mechanical
efficiency of your paradigm animal -- the adult male.
The OTHER gender and the rest of the species
matter as well. The OTHER gender has two very
different modes: --
(A) the quadrupedal with the (inevitable) infant
slung underneath, and the mother having four limbs
available for fast travel, for running, climbing, feeding,
foraging, fighting, and everything else;
(B) the bipedal, with the infant awkwardly carried
in two arms, making running, tree-climbing, and nearly
everything else, next to impossible.
> Firstly, in order for practical survival on the savanna, we are
> fairly close to the MINIMUM efficiency for long-distance travel.
> Chimpanzees are WAY below it, and a population would die out in
> short order. Observed figures for their movements are about
> 2-6 km a day.
And that's the adult male chimps, not the female
ones, with babies and other young to care for.
> For survival on the savanna, 15-20 is needed.
It's nuts to think that females with babies and other
young would go on the open savanna in any case.
> The second is that the 'transition' is a MAJOR change, and must
> have involved many mutations over hundreds of generations. The
> probabilities are such that it could happen ONLY if there is a
> definite survival advantage towards bipedalism at almost all
> stages and there is ALMOST NEVER a survival advantage for
> reversion.
Agreed. It had to be a small, isolated population,
no longer under the constraints facing all other
chimps, of having to spend most of their time
in, or close to trees. And where, in every
generation, there were significant advantages
to being more and more bipedal.
Paul.
Nick Maclaren
In article <LWlqc.8173$qP2....@news.indigo.ie>,
"Paul Crowley" <slkwuoiut...@slkjlskjoioue.com> writes:
|>
|> It's nuts to think that females with babies and other
|> young would go on the open savanna in any case.
|>
|> no longer under the constraints facing all other
|> chimps, of having to spend most of their time
|> in, or close to trees. And where, in every
|> generation, there were significant advantages
|> to being more and more bipedal.
Yes, that is my conclusion. They could well have moved out
onto the savanna, but only AFTER being able to travel 20 km
in a day (yes, with young) and AFTER developing enough weapon
technology to discourage the group predators. Modern humans
can do both, but chimpanzees can do neither.
That could have been fairly early, but could not have been
during the period that we were developing effective bipedal
locomotion. That simply HAD to occur under different
conditions. Unless Darwin was completely wrong, of course :-)
Regards,
Nick Maclaren.
Jason Eshleman
>Firstly, in order for practical survival on the savanna, we are
>fairly close to the MINIMUM efficiency for long-distance travel.
>Chimpanzees are WAY below it, and a population would die out in
>short order. Observed figures for their movements are about
>2-6 km a day. For survival on the savanna, 15-20 is needed.
You made the claim that any change would result in an intermediate that
was less efficient. I rebutted that there is data suggesting that this is
not the case. You ignored this data and brought up the savanna. Please
note that you brought this up. I am "ignoring" this because it's a
strawman. Please indicate where I linked any of the argument to "survival
on the savanna."
>The second is that the 'transition' is a MAJOR change, and must
>have involved many mutations over hundreds of generations. The
>probabilities are such that it could happen ONLY if there is a
>definite survival advantage towards bipedalism at almost all
>stages and there is ALMOST NEVER a survival advantage for
>reversion.
We do not know how many mutations it takes to alter a generic ape morph
into the morph of an early committed biped. This is a major change
indeed. Putting "major" and "almost never" in allcaps isn't a rebuttal
against me. It doesn't indicate something I've ignored. It simply
indicates your own personal incredulity that intermediate stages wouldn't
be favored. You've offered no reason or explanation for why this is not
the case and have totally ignored actual data suggesting that this isn't
the case.
You are only partially correct that a change can occur only if there is a
definite survival advantage at every stage. There are many ways for
populations to evolve. Minor survival advantages can drive evolution with
the probability of fixation of the new allele being exactly equal to the
relative survival value (regardless of population size). While I suspect
strongly that the change towards a bipedal gait was a selective one, drift
also contributes to a significant amount of evolutionary change. In
absence of strong selection, drift plays a larger role, sometimes moving
towards less strongly selected traits. This is undergrad population
genetics stuff here.
If indeed bipedalism was driven by a need for greater efficiency (note the
word if here) and if data is correct that chimp-like bipedalism and
chimp-like quadrupedalism are virtually identical in their efficiency, any
change that increased the efficiency of one form of locomotion would be
favored and those alleles responsible for this change would tend towards
fixation at exactly the probability of the relative survival advantage
conveyed by those alleles.
Jim McGinn
> >All plausible transitions between a chimpanzee-like ape and an
> >early bipedal human involve a phase where the animal would have
> >been even worse than a chimpanzee at long-distance travel. That
> >change could NOT have happened on the savanna. And, unless there
> >was a survival advantage to developing efficient bipedal locomotion,
> >Darwinism implies that we should have reverted. We didn't.
>
> This is incorrect. Not all plausible transitions rely on a local maximum
> in the transition. I realize that it's a data poor area currently, but
> there *(IS* evidence that a bipedal gait is no less *efficient* than a
> quadrupedal one for chimps. If this really is the case (again, it's data
> poor, but that is what the limited data indicates) then it isn't
> necessarily so that a shift would be less efficient. The assertion that
> knucklewalking would have been a local maximum isn't necessarily so.
Jason,
I think you have to explain what a "local maximum" is and
what it has to do with this conversation.
Jim
Jim McGinn
> >Firstly, in order for practical survival on the savanna, we are
> >fairly close to the MINIMUM efficiency for long-distance travel.
> >Chimpanzees are WAY below it, and a population would die out in
> >short order. Observed figures for their movements are about
> >2-6 km a day. For survival on the savanna, 15-20 is needed.
>
> You made the claim that any change would result in an intermediate that
> was less efficient. I rebutted that there is data suggesting that this is
> not the case. You ignored this data and brought up the savanna.
He didn't ignore it. He addressed it and pointed out that this,
"data," is not applicable to the issue at hand.
Please
> note that you brought this up. I am "ignoring" this because it's a
> strawman.
It's not a strawman.
Please indicate where I linked any of the argument to "survival
> on the savanna."
Game player. Why don't you tell us what environment you do propose
and stop playing games. The truth, Jason, is that you like to keep it
vague and pretend that you are saying something when in actuality you
are saying little of anything at all.
>
> >The second is that the 'transition' is a MAJOR change, and must
> >have involved many mutations over hundreds of generations. The
> >probabilities are such that it could happen ONLY if there is a
> >definite survival advantage towards bipedalism at almost all
> >stages and there is ALMOST NEVER a survival advantage for
> >reversion.
>
> We do not know how many mutations it takes to alter a generic ape morph
> into the morph of an early committed biped. This is a major change
> indeed. Putting "major" and "almost never" in allcaps isn't a rebuttal
> against me. It doesn't indicate something I've ignored. It simply
> indicates your own personal incredulity that intermediate stages wouldn't
> be favored.
Maybe it's the fact that these intermediate stages exist as little
more than a vague notion in your mind.
You've offered no reason or explanation for why this is not
> the case and have totally ignored actual data suggesting that this isn't
> the case.
>
> You are only partially correct that a change can occur only if there is a
> definite survival advantage at every stage. There are many ways for
> populations to evolve. Minor survival advantages can drive evolution with
> the probability of fixation of the new allele being exactly equal to the
> relative survival value (regardless of population size).
Pseudoscience. This is whacko stuff that's become popularized by
people that don't fully comprehend genetic analysis.
While I suspect
> strongly that the change towards a bipedal gait was a selective one, drift
> also contributes to a significant amount of evolutionary change. In
> absence of strong selection, drift plays a larger role, sometimes moving
> towards less strongly selected traits. This is undergrad population
> genetics stuff here.
It's not undergrad population genetics. There's no such thing as
undergrad population genetics. This is pure nonsense.
>
> If indeed bipedalism was driven by a need for greater efficiency (note the
> word if here) and if data is correct that chimp-like bipedalism and
> chimp-like quadrupedalism are virtually identical in their efficiency, any
> change that increased the efficiency of one form of locomotion would be
> favored and those alleles responsible for this change would tend towards
> fixation at exactly the probability of the relative survival advantage
> conveyed by those alleles.
Blah, blah, blah. You don't have the slightest clue.
Jim
Nick Maclaren
In article <c8dem6$mfq$1...@woodrow.ucdavis.edu>,
j...@veni.ucdavis.edu (Jason Eshleman) writes:
|>
|> You made the claim that any change would result in an intermediate that
|> was less efficient. I rebutted that there is data suggesting that this is
|> not the case.
In the postings of yours that I noticed, you claimed there was such
data, but failed to provide it. The data that I saw you provide
was merely that a chimpanzee can move bipedally with tolerable
efficiency for slow movement over short distances - hell, we can
move quadrupedally under the same conditions!
|> You ignored this data and brought up the savanna. Please
|> note that you brought this up. I am "ignoring" this because it's a
|> strawman. Please indicate where I linked any of the argument to "survival
|> on the savanna."
In this respect, I apologise. I assigned the remark to the wrong
person.
Regards,
Nick Maclaren.
Jason Eshleman
> In article <c8dem6$mfq$1...@woodrow.ucdavis.edu>,
> j...@veni.ucdavis.edu (Jason Eshleman) writes:
> |>
> |> You made the claim that any change would result in an intermediate that
> |> was less efficient. I rebutted that there is data suggesting that this is
> |> not the case.
>
> In the postings of yours that I noticed, you claimed there was such
> data, but failed to provide it. The data that I saw you provide
> was merely that a chimpanzee can move bipedally with tolerable
> efficiency for slow movement over short distances - hell, we can
> move quadrupedally under the same conditions!
The data was presented in Taylor and Roundtree (1973) as reported by
Rodman and McHenry (1980 IIRC). The data shows that chimps are
*equally* effiencient (energy expended per unit of distance moved)
bipedally or quadrupedally and less efficient than we are bipedally.
(I am not sure where you decided to interject "tolerable" to the
efficiency. It isn't a matter of tolerating, but rather a matter of
direct comparison.) The samples used were small and there are
problems with it. The study should, and I believe will soon, be
redone with a larger sample under more realistic conditions
controlling for a greater number of variables, but currently, that is
what the data suggests.
Nick Maclaren
In article <b7af43cb.04051...@posting.google.com>,
j...@ucdavis.edu (Jason Eshleman) writes:
|> nm...@cus.cam.ac.uk (Nick Maclaren) wrote in message news:<c8f60t$qmo$1...@pegasus.csx.cam.ac.uk>...
|> > In article <c8dem6$mfq$1...@woodrow.ucdavis.edu>,
|> > j...@veni.ucdavis.edu (Jason Eshleman) writes:
|> > |>
|> > |> You made the claim that any change would result in an intermediate that
|> > |> was less efficient. I rebutted that there is data suggesting that this is
|> > |> not the case.
|> >
|> > In the postings of yours that I noticed, you claimed there was such
|> > data, but failed to provide it. The data that I saw you provide
|> > was merely that a chimpanzee can move bipedally with tolerable
|> > efficiency for slow movement over short distances - hell, we can
|> > move quadrupedally under the same conditions!
|>
|> The data was presented in Taylor and Roundtree (1973) as reported by
|> Rodman and McHenry (1980 IIRC). The data shows that chimps are
|> *equally* effiencient (energy expended per unit of distance moved)
|> bipedally or quadrupedally and less efficient than we are bipedally.
|> (I am not sure where you decided to interject "tolerable" to the
|> efficiency. It isn't a matter of tolerating, but rather a matter of
|> direct comparison.) The samples used were small and there are
|> problems with it. The study should, and I believe will soon, be
|> redone with a larger sample under more realistic conditions
|> controlling for a greater number of variables, but currently, that is
|> what the data suggests.
Published WHERE? I am asking for a reference, not mere decorative
detail.
Also, in the context of the previous 'debate', I pointed out
that energetic efficiency was only ONE of the forms of efficiency
(and arguably one of the least important). In particular, the
ability to run and climb are MUCH more important than the ability
to walk when escaping predators. I suspect that the data you are
talking about is merely relevant to walking around gathering food
and so on. Bears often do that bipedally - so what?
I inserted 'tolerable' to distinguish it from (say) a sloth's
ability to travel on the ground, and to make it clear that I was
talking about functional effectiveness in an evolutionary sense.
Chimpanzees have several forms of locomotion that are tolerable for
gathering food (quadrupedal, bipedal and brachiating), but I believe
only two that are tolerable for escaping predators. And they have
none that are tolerable for travelling between waterholes over most
of the savanna in the dry season.
You can change 'tolerable' to 'adequate' if you like, but I am
talking Darwinistically. An ability is not tolerable if it would
lead to the magnitude of loss of survival potential IN CONTEXT
that would drive natural selection another way. As I said, all
known data indicates that the skeletal and muscular changes needed
for improved bipedal locomotion would make both quadrupedal and
brachiating locomotion less efficient, and THAT loss is the issue.
We know that both such abilities are used to escape predators.
I am beginning to think that I am the only classical Darwinist
posting here :-(
Regards,
Nick Maclaren.
Jim McGinn
The data that I saw you provide
> > was merely that a chimpanzee can move bipedally with tolerable
> > efficiency for slow movement over short distances
The data shows that chimps are
> *equally* effiencient bipedally or quadrupedally and less efficient than we are bipedally.
Mikey Brass
>|> The data was presented in Taylor and Roundtree (1973) as reported by
>|> Rodman and McHenry (1980 IIRC). The data shows that chimps are
>|> *equally* effiencient (energy expended per unit of distance moved)
>|> bipedally or quadrupedally and less efficient than we are bipedally.
The data I saw in Wolpoff's Paleoanthropology (1999) suggested that
chimps were more energy efficient quadrupedally.
> You can change 'tolerable' to 'adequate' if you like, but I am
> talking Darwinistically. An ability is not tolerable if it would
> lead to the magnitude of loss of survival potential IN CONTEXT
> that would drive natural selection another way. As I said, all
> known data indicates that the skeletal and muscular changes needed
> for improved bipedal locomotion would make both quadrupedal and
> brachiating locomotion less efficient, and THAT loss is the issue.
> We know that both such abilities are used to escape predators.
>
> I am beginning to think that I am the only classical Darwinist
> posting here :-(
No you aren't alone. I agree with the above.
--
===========
Mikey Brass
MA in Archaeology student
"The Antiquity of Man" http://www.antiquityofman.com
Book: "The Antiquity of Man: Artifactual, fossil and gene records
explored"
- "If we knew what we were doing, it wouldn't be called research, would
it?"
(Albert Einstein)
Nick Maclaren
In article <Xns94EF6391FA10Bmi...@195.8.68.217>,
Mikey Brass <mi...@nospam.antiquityofman.com> writes:
|> nm...@cus.cam.ac.uk (Nick Maclaren) wrote in
|> news:c8honi$6lt$1...@pegasus.csx.cam.ac.uk:
|>
|> >|> The data was presented in Taylor and Roundtree (1973) as reported by
|> >|> Rodman and McHenry (1980 IIRC). The data shows that chimps are
|> >|> *equally* effiencient (energy expended per unit of distance moved)
|> >|> bipedally or quadrupedally and less efficient than we are bipedally.
|>
|> The data I saw in Wolpoff's Paleoanthropology (1999) suggested that
|> chimps were more energy efficient quadrupedally.
This is where the conditions are so important. We are tolerably
efficient quadrupedally (hands and knees - NOT hands and feet) for
short distances and at very low speeds, but are catastrophically
inefficient at higher speeds. You don't need an ergonometer to
check that, either!
My guess is that quite a lot of animals (bears, chimpanzees and
others) are the same in reverse. And it is the conditions which
make a difference to survival that are relevant to evolution, at
least according to Darwin.
|> > You can change 'tolerable' to 'adequate' if you like, but I am
|> > talking Darwinistically. An ability is not tolerable if it would
|> > lead to the magnitude of loss of survival potential IN CONTEXT
|> > that would drive natural selection another way. As I said, all
|> > known data indicates that the skeletal and muscular changes needed
|> > for improved bipedal locomotion would make both quadrupedal and
|> > brachiating locomotion less efficient, and THAT loss is the issue.
|> > We know that both such abilities are used to escape predators.
|> >
|> > I am beginning to think that I am the only classical Darwinist
|> > posting here :-(
|>
|> No you aren't alone. I agree with the above.
Excellent. There are now at least two :-)
Regards,
Nick Maclaren.
Mikey Brass
> My guess is that quite a lot of animals (bears, chimpanzees and
> others) are the same in reverse. And it is the conditions which
> make a difference to survival that are relevant to evolution, at
> least according to Darwin. It's called context :-)
Quite right. It's adaptations to the existing envrionments and the food
procurement strategies enabling survival, as well as obviously avoiding
being killed.
> Excellent. There are now at least two :-)
Yes.
Jason Eshleman
Rodman and McHenry was, IIRC, in the Am J. of Phys. Anth. I do not
recall where Taylor and Roundtree presented their findings.
> Also, in the context of the previous 'debate', I pointed out
> that energetic efficiency was only ONE of the forms of efficiency
> (and arguably one of the least important). In particular, the
> ability to run and climb are MUCH more important than the ability
> to walk when escaping predators. I suspect that the data you are
> talking about is merely relevant to walking around gathering food
> and so on. Bears often do that bipedally - so what?
I think you are confusing efficiency with effectiveness. Efficiency
is energy expended per unit traveled. It is not related to escape
speed from a predator. I suspect that fleeing predators wasn't as
signficant a problem for early bipeds as some here want to make it out
to be. There's significant debate among primatologists as to the
importance of (non-human) predation to modern primate societies. A
speedy escape isn't the only way to deal with a predator.
> I inserted 'tolerable' to distinguish it from (say) a sloth's
> ability to travel on the ground, and to make it clear that I was
> talking about functional effectiveness in an evolutionary sense.
Again, do not confuse efficiency (energy expended to complete a task)
with effectiveness.
> Chimpanzees have several forms of locomotion that are tolerable for
> gathering food (quadrupedal, bipedal and brachiating), but I believe
> only two that are tolerable for escaping predators. And they have
> none that are tolerable for travelling between waterholes over most
> of the savanna in the dry season.
The efficiency equation is a scenario where the evolution of this form
of locomotion wasn't driven by predation. There are again other ways
to escape predators.
> You can change 'tolerable' to 'adequate' if you like, but I am
> talking Darwinistically. An ability is not tolerable if it would
> lead to the magnitude of loss of survival potential IN CONTEXT
> that would drive natural selection another way. As I said, all
> known data indicates that the skeletal and muscular changes needed
> for improved bipedal locomotion would make both quadrupedal and
> brachiating locomotion less efficient, and THAT loss is the issue.
> We know that both such abilities are used to escape predators.
I'm talking Darwinistically too. I'm simply not assuming that the
only selective pressure is predation pressure. Please do look at the
literature on chimps and predation. A speedy escape is not the
sum-total of the list of their counter-predation measures. It's also
clear that the earliest bipeds retained clear arboreal adaptations.
Not sure that it's true that the changes to make an early biped would
greatly decrease the ability to brachiate. Do you have evidence of
this?
> I am beginning to think that I am the only classical Darwinist
> posting here :-(
I'm not sure what you do to define yourself as a classical Darwinist.
Evolution is not a synonym for natural selection. There are other
mechanisms. And selection is not a synonym for predation. There are
other selective agents.
Nick Maclaren
In article <b7af43cb.04052...@posting.google.com>,
j...@ucdavis.edu (Jason Eshleman) writes:
|>
|> Rodman and McHenry was, IIRC, in the Am J. of Phys. Anth. I do not
|> recall where Taylor and Roundtree presented their findings.
I will see if I can track it down.
|> I think you are confusing efficiency with effectiveness. Efficiency
|> is energy expended per unit traveled. It is not related to escape
|> speed from a predator. I suspect that fleeing predators wasn't as
|> signficant a problem for early bipeds as some here want to make it out
|> to be. There's significant debate among primatologists as to the
|> importance of (non-human) predation to modern primate societies. A
|> speedy escape isn't the only way to deal with a predator.
Not in English. If I had meant that restricted form of efficiency,
I would have said so. From the OED:
2. a. Fitness or power to accomplish, or success in accomplishing,
the purpose intended; adequate power, effectiveness, efficacy.
3. Mech. and Physics. b. The ratio of useful work performed to the
total energy expended or heat taken in.
Note that the meaning I was using comes first.
Regards,
Nick Maclaren.
Lee Olsen
Taylor and Roundtree 1973
http://www.google.com/search?hl=en&lr=&ie=UTF-8&safe=off&q=%22Taylor+and+Roundtree+1973%22&btnG=Search
Rodman, P. S., and H. M. McHenry. 1980. Bioenergetics and
the origin of hominid bipedalism. American Journal of
Physical Anthropology 52: 103–106.
I didn't have any trouble finding the references from the information
given. The question to you then--- does your mother still change your
diapers and help you blow your nose?
snip
Jim McGinn
> > My guess is that quite a lot of animals (bears, chimpanzees and
> > others) are the same in reverse. And it is the conditions which
> > make a difference to survival that are relevant to evolution, at
> > least according to Darwin. It's called context :-)
>
> Quite right. It's adaptations to the existing envrionments and the food
> procurement strategies enabling survival, as well as obviously avoiding
> being killed.
>
> > Excellent. There are now at least two :-)
>
> Yes.
Okay, let's cut to the chase here. The point is that
anybody (Mikey) that continues to maintain that bipedalism
evolved as a walking efficiency adaptation is a goddamn
dumbass. But the big question still remains on the table:
how/why did bipedalism evolve?
Jim
Mikey Brass
news:ac6a5059.04052...@posting.google.com:
I am never surprised when you begin to insult but I am mildly annoyed you
deliberately miscontrued my environmental adaptation & food procurement
strategies into "walking efficiency adaptaion".
The following may be of interest to readers and lurkers alike (and before
Jim asks again, no I am not going to summarise the body for him) :
Bipedality in Chimpanzee (Pan troglodytes) and Bonobo (Pan paniscus):
Testing Hypotheses on the Evolution of Bipedalism
Elaine N. Videan and W.C. McGrew
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 118:184–190 (2002)
ABSTRACT A host of ecological, anatomical, and
physiological selective pressures are hypothesized to have
played a role in the evolution of hominid bipedalism. A
referential model, based on the chimpanzee (Pan troglodytes)
and bonobo (Pan paniscus), was used to test
through experimental manipulation four hypotheses on
the evolution of hominid bipedalism. The introduction of
food piles (Carry hypothesis) increased locomotor bipedality
in both species. Neither the introduction of branches
(Display hypothesis) nor the construction of visual barriers
(Vigilance hypothesis) altered bipedality in either species.
Introduction of raised foraging structures (Forage
hypothesis) increased postural bipedality in chimpanzees.
These experimental manipulations provided support for
carrying of portable objects and foraging on elevated fooditems
as plausible mechanisms that shaped bipedalism in
hominids.
Brief Communication: Arboreal Bipedalism in Bwindi Chimpanzees
Craig B. Stanford
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 119:87–91 (2002)
ABSTRACT Evidence of the form and function of bipedal
behavior in nonhuman primates provides critical
evidence to test theories about the origins of hominid
bipedalism. Bipedalism has long been considered an evolutionarily
interesting but rare behavior in wild chimpanzees.
During May 2001, chimpanzees of the Ruhija community
in the Bwindi Impenetrable National Park,
Uganda, engaged in an exceptional frequency of arboreal
bipedalism when feeding in large Ficus trees. Seventyeight
bipedal bouts of at least 5 sec duration were recorded
for the entire community (0.49 bouts/hr), with a mean
duration of 13.7 sec ( 1.6 sec). The animals employed
many variations on the bipedal postural theme, ranging
from erect standing on the largest substrates while grasping
overhead limbs for support, to standing on one leg
while suspending the other leg in space, to extended-lean
standing, in which bipedal standing transitioned into horizontal
arm-leg suspension as the animal reached for more
distant fruits. Bipedalism was used as part of a behavioral
repertoire that integrated brachiation, four-limbed suspension,
and forelimb-supported standing for effective smallfruit
foraging. These observations suggest that under certain
ecological conditions, arboreal bipedalism can be an important
posture for wild chimpanzees, and may have been an
important behavioral precursor to full terrestrial bipedalism.
DATA FROM END OF ARTICLE Data from Bwindi chimpanzees,
like those of Hunt (1994), suggest that forest-living
chimpanzees may be as bipedal, although on different
substrates, as those living in more open landscapes.
Chimpanzees have long been a model for the evolution
of human behavior, and chimpanzee locomotion
has long been used as evidence in debates about
the locomotor patterns of the earliest hominids.
Washburn (1963, 1968), for example, saw terrestrial
knuckle-walking as the way our immediate prehominid
ancestors must have traveled, and advocated
early terrestriality on emerging savannas as
the behavioral ecological shift that preadapted prehominids
to bipedalism. Bipedalism and its variants
may, however, have emerged from an arboreal habitus
that placed an evolutionary premium on foraging
benefits that accrued to apes during small-object
feeding (Tuttle, 1981; Rose, 1984; Hunt, 1994). Further
studies of bipedal posture and locomotion in
free-ranging great apes can address this question as
a key complement to the fossil record.
Back to my sentence:
"It's adaptations to the existing envrionments and the food
procurement strategies enabling survival, as well as obviously avoiding
being killed."
--