bipedally wading gorillas
marc verhaegen
last programme suggested that this area might have been where the first
hominids evolved. It showed gorillas wading in water up to their waists.
There are open areas in the forest, often with lakes (called bais?) where
large numbers of gorillas go to eat the aquatic vegetation, as do the forest
elephants.
Rich Travsky
Of doubtful use now that there's a hominid with apparent bipedal traits in
a totally different area and dated at 6 mya.
This has some bearing on the dates for the homo-chimp-gorilla split.
Neurocop
"Rich Travsky" <tra...@REMOVEhotmail.com> wrote in message
news:3A930D81...@REMOVEhotmail.com...
> Of doubtful use now that there's a hominid with apparent bipedal traits in
> a totally different area and dated at 6 mya.
>
> This has some bearing on the dates for the homo-chimp-gorilla split.
NONETHELESS, the implication is that wading may have been a promoter of
bipedalism. This is an interesting idea, and I haven't encountered it
before. The physical factors associated with wading (bouyancy especially)
would promote an upright posture IN WATER). The wading ape could have taken
the lesson back to the land. Marc, this is a really good idea. You should
take it up. I assume that you were heading in this direction. If not, feel
free to run with the ball.
Nick Capozzoli
Richard Wagler
Neurocop wrote:
Two points. Firstly wading may induce bipedalism in primates. So do a lot of
other things.
A great many primates exhibit the ability to adopt bipedalism. Secondly the
problem is not
lessening weight but developing the musculature spec the gluteus maximus, to
carry it.
Wading would *lessen* the selective pressure to do this - not encourage a
positive
response to it. Wading is essentially a sedentary activity. Typically waders are
seeking
food or crossing a stream. The role that wading could have played in producing a
long striding, distance walker like Homo would be minor. Could it have played a
role?
Perhaps. Could it have been the major impetus? Can't see why.
Rick Wagler
Manuel Ritto Correa
> NONETHELESS, the implication is that wading may have been a promoter of
> bipedalism. This is an interesting idea, and I haven't encountered it
> before.
Have you heard about the aquatic ape theory?
See: http://www.geocities.com/Athens/5168/aat/leaflet.html
> The physical factors associated with wading (bouyancy especially)
> would promote an upright posture IN WATER). The wading ape could have taken
> the lesson back to the land. Marc, this is a really good idea. You should
> take it up. I assume that you were heading in this direction. If not, feel
> free to run with the ball.
Manuel Correa
--
In mathematics you don't understand things. You just get used to
them.- J. von Neumann
Margo Uller
the premise was that humans evolved in or near water. made sense to me I
have never forgotten it so when I saw the program you mentioned it rang
a bell . As humans we are attracted to water in a very primative way ,
The Discovery channel had a program that stated the dispersal of humans
was along coastlines rather than marching through the woods and
mountains. This idea will probely be proven just like the theory of
plate tectonics which was laughed at years ago is accepted now.
marc verhaegen
Manuel Ritto Correa heeft geschreven in bericht
<3A93A4EE...@civil.ist.utl.pt>...
>> NONETHELESS, the implication is that wading may have been a promoter of
>> bipedalism. This is an interesting idea, and I haven't encountered it
>> before.
>
>Have you heard about the aquatic ape theory?
>See: http://www.geocities.com/Athens/5168/aat/leaflet.html
Some other websites:
AAT files at http://www.onelist.com/community/AAT
The best scientific site on AAT (pro & con) IMO is
http://allserv.rug.ac.be/~mvaneech/Symposium.html
Introduction by prof.Tobias
http://archive.outthere.co.za/98/dec98/disp1dec.html
My websites (on African ape & human evolution, and speech origins):
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
http://www.flash.net/~hydra9/marcaat.html
http://jurix.rechten.rug.nl/rth/ess/ess50.htm
http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html
http://www.infres.enst.fr/confs/evolang/actes/_actes74.html
Other websites on AAT:
http://www.logres.net/dawn/apeart.html
http://www.primate.wisc.edu/pin/aquatic.html
Kate Douglas in New Scientist "Taking the plunge"
http://www.newscientist.com/nlf/1125/taking.html ;
Simon Bearde: BBC online "Flood brothers"
http://www.bbc.co.uk/nature/animals/features/141index.shtml
Some other website possibly of interest:
Acheulean tools amid shellfish & corals in Eritrea ~0.125 Ma
http://www.exn.ca/hominids/outofafrica.cfm
Marcel Williams: Pliocene maps Red Sea
http://members.telocity.com/~hydra9/afargeology.html ;
Semi-aquatic rhinos?
http://unisci.com/stories/20004/1115002.htm ;
Semi-aquatic elephants?
http://unisci.com/stories/19992/0511993.htm
http://204.202.137.117/sections/science/DailyNews/elephants990511.html
http://www.lifemag.com/Life/pictday/wppa03.html
>> The physical factors associated with wading (bouyancy especially)
>> would promote an upright posture IN WATER). The wading ape could have
taken
>> the lesson back to the land. Marc, this is a really good idea. You should
>> take it up. I assume that you were heading in this direction. If not,
feel
>> free to run with the ball. Manuel Correa
We've written a few papers on it. :-) We think early hominids lived in
coastal or swamp forests, where they, like proboscis monkeys, climbed trees
& waded on 2 legs in shallow water, and perhaps on the knuckles in very
shallow water. From this kind of wading-climbing creature, the Homo species
evolved: with the Pleistocene coolings (sea levels dropped: vast tidal areas
on continental shelves, less forests & less climbing adaptations) they
adapted to the waterside (Indian Ocean? from Africa to Java & along the
rivers inland?): more swimming & diving for aquatic foods (sandy beaches?
reef back channels? offshore islands?): hence more linear build, longer
wading-legs, dexterity, larger brains & stone use to open coconuts &
shellfish & butcher dugongs etc. Voluntary breath hold for diving: =
beginning of speech? (In the fossils record we see mostly the inland
sidebranches since the Pleistocene coasts were often 100 metres below the
present sea level.)
Marc
Michael Miller
"Margo Uller" <margo...@webtv.net> wrote in message
news:6657-3A9...@storefull-101.iap.bryant.webtv.net...
Plate tectonics did get off a little slow in the scientific community. When
Robert Bakker was a grad student at Yale, he mentioned (and this is in his
book "The Dinosaur Heresies") that, while in the university's museum, the
display of the brontosaurus struck him as a little peculiar. To cut to the
chase, greatly influenced by this notion, Bakker went on to propose that
dinos were warm-blooded creatures rather than the cold-blooded reptiles we
once thought they were to have been. Actually, the jury is still out on
that, but Bakker did present some very impelling evidence which would
suggest this.
What I am saying is this: the idea that bipedalism could be a product of
wading seems to serve as a curiosity at this time, but until more evidence
can be presented (I won't ignore anything) I can only fall back on that
which seems more plausible - that we developed this mode of transportation
as a means of traveling long distances with more ease over dry ground
quicker.
And if I seem to be misguided r missing something, please slap me and tell
me why. I don't want to leave any stone unturned.
Neurocop
"Manuel Ritto Correa" <mco...@civil.ist.utl.pt> wrote in message
news:3A93A4EE...@civil.ist.utl.pt...
>
> > NONETHELESS, the implication is that wading may have been a promoter of
> > bipedalism. This is an interesting idea, and I haven't encountered it
> > before.
>
> Have you heard about the aquatic ape theory?
Sure have heard of it. But this particular spin on it is a bit different.
Neurocop
"marc verhaegen" <marc.ve...@village.uunet.be> wrote in message
news:3a943308$0$4496$73be...@news.be.uu.net...
Thanks, Marc. I know that you AAT guys (and gals...such as Ms. Morgan) have
argued the AA origins of Homo, but this latest emphasis on the bouyancy of
water to free the hands is slightly different, it seems, from the emphases
of the previous arguments, such as the ones about airway control and speech,
loss of body hair, sweat gland function, etc...
Nick Capozzoli
Rich Travsky
Usually ignored by AA types is the small amount of time spent in such wading
behaviors. Hardly compelling. (Marc is fond of a Nat Geo article showing a
gorilla
in water. He never mentions that the photographer waited 3 weeks (I believe it
was) to get the shot.
Since the gorillas (add chimps if you like) spent the majority of their time on
*land*, bipedal behaviors there are more relevant. I have seen far more footage
of chimps and gorillas indulging in bipedal activities on land. Threat displays,
carrying things, looking around, fighting, etc.
Richard Wagler
Rich Travsky wrote:
> Richard Wagler wrote:
> >
>
> > Two points. Firstly wading may induce bipedalism in primates. So do a lot of
> > other things.
> > A great many primates exhibit the ability to adopt bipedalism. Secondly the
> > problem is not
> > lessening weight but developing the musculature spec the gluteus maximus, to
> > carry it.
> > Wading would *lessen* the selective pressure to do this - not encourage a
> > positive
> > response to it. Wading is essentially a sedentary activity. Typically waders are
> > seeking
> > food or crossing a stream. The role that wading could have played in producing a
> >
> > long striding, distance walker like Homo would be minor. Could it have played a
> > role?
> > Perhaps. Could it have been the major impetus? Can't see why.
>
> Usually ignored by AA types is the small amount of time spent in such wading
> behaviors. Hardly compelling. (Marc is fond of a Nat Geo article showing a
> gorilla
> in water. He never mentions that the photographer waited 3 weeks (I believe it
> was) to get the shot.
>
> Since the gorillas (add chimps if you like) spent the majority of their time on
> *land*, bipedal behaviors there are more relevant. I have seen far more footage
> of chimps and gorillas indulging in bipedal activities on land. Threat displays,
> carrying things, looking around, fighting, etc.
The other point they can't seem to grasp is that the vast majority
of primates inhabit tropical rain forests where the necessity of
dealing with very wet conditions is everpresent - swamps,
seasonally flooded forests and the like. None have, despite
endless opportunities to do so, have become habitual bipeds due
to extensive - potentially at least - bouts of wading.
The only primates who became habitual bipeds - with the
arguable exception of Oreopithecus - inhabited a part of
Africa where major, long term climate change was dramatically
lessening the opportunities or necessity for engaging in this
sort of behaviour.
As for Oreopithecus its bipedalism may have been much
more postural than an efficient or reliable means of locomotion.
Rick Wagler
marc verhaegen
Margo Uller heeft geschreven in bericht
<6657-3A9...@storefull-101.iap.bryant.webtv.net>...
I think you're completely right.
Elaine Morgan 1972 "The descent of woman" Souvenir London.
She's at http://www.onelist.com/community/AAT
Marc
marc verhaegen
Michael Miller heeft geschreven in bericht ...
>What I am saying is this: the idea that bipedalism could be a product of
>wading seems to serve as a curiosity at this time, but until more evidence
>can be presented (I won't ignore anything) I can only fall back on that
>which seems more plausible - that we developed this mode of transportation
>as a means of traveling long distances with more ease over dry ground
>quicker.
If bipedalism had been better for traveling long distances on land, a lot of
terrestrial animals would have been bipedal. (Not for transportation:
transport over water seems to have been more important than over land.)
Bipedalism as a product of wading is no curiosity at all. To the contrary,
the most-bipedal non-human primate is exactly the one that wades most
frequently: the proboscis monkey (mangrove swamp).
Marc Verhaegen
http://www.onelist.com/community/AAT
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
marc verhaegen
Rich Travsky heeft geschreven in bericht
<3A9546D3...@REMOVEhotmail.com>...
>Usually ignored by AA types is the small amount of time spent in such
wading
>behaviors. Hardly compelling. (Marc is fond of a Nat Geo article showing a
>gorilla
>in water. He never mentions that the photographer waited 3 weeks (I believe
it
>was) to get the shot.
As usual you miss the point. The wading gorillas show the possibility & how
a semi-aquatic life could have evolved.
marc verhaegen
Neurocop heeft geschreven in bericht
<9726av$car$1...@slb4.atl.mindspring.net>...
.....
>Thanks, Marc. I know that you AAT guys (and gals...such as Ms. Morgan) have
>argued the AA origins of Homo, but this latest emphasis on the bouyancy of
>water to free the hands is slightly different, it seems, from the emphases
>of the previous arguments, such as the ones about airway control and
speech,
>loss of body hair, sweat gland function, etc... Nick Capozzoli
Sorry, yes, I misread something I believe. But how can buoyancy help
understand bipedalism?
Marc
Rich Travsky
>
> Rich Travsky heeft geschreven in bericht
> <3A9546D3...@REMOVEhotmail.com>...
>
> >Usually ignored by AA types is the small amount of time spent in such
> wading
> >behaviors. Hardly compelling. (Marc is fond of a Nat Geo article showing a
> >gorilla
> >in water. He never mentions that the photographer waited 3 weeks (I believe
> it
> >was) to get the shot.
>
> As usual you miss the point. The wading gorillas show the possibility & how
> a semi-aquatic life could have evolved.
My dog goes in the water too, but how many dogs have a semi aquatic
lifestyle? Ditto for any other animal that can wade once in a while...
Neurocop
> Sorry, yes, I misread something I believe. But how can buoyancy help
understand bipedalism?
>
> Marc
I don't believe that bouyancy was the sole or even main evolutionary
determinant of bipedalism. I believe that for pure terrestrial locomotor
efficiency in vertebrates quadrupedalism is better. The main reason
bipedalism developed in humans was that it freed the forelimbs for some
function that more than compensated for bipedalism's lower efficiency.
Manipulative ability, especially tool use, drove the evolutionary
compromise.
The think I like about the wading scenario is that it provides a mechanism
to facilitate the switch to an upright posture. It is physically demanding
for quadrupeds or even brachiators to sustain an upright posture for any
length of time. Most apes that I have observed at the zoo (sorry, I'm an
urban anthropologist at best) tend to sit on their butts when using their
hands for any serious manipulation.
Wading at least chest deep would provide a brachiator (which I prefer to
think of as a facultative biped) the bouyancy to use the hands for extended
manipulation without having to expend as much energy as a brachiator that
tried the same feat on terra firma.
The wading scenario serves the same function of facilitating an anatomic
transformation that an enzyme serves in catalyzing a chemical reaction.
That, in a nutshell, is what I like about your hypothesis.
Nick Capozzoli
Gerrit Hanenburg
>Bipedalism as a product of wading is no curiosity at all. To the contrary,
>the most-bipedal non-human primate is exactly the one that wades most
>frequently: the proboscis monkey (mangrove swamp).
Now you are being dishonest.
You deliberately repeat a statement as fact while you can't
substantiate it.
Gerrit
Manuel Ritto Correa
> > Have you heard about the aquatic ape theory?
> > Manuel Correa
>
> Sure have heard of it. But this particular spin on it is a bit different.
Well.
Let me tell you I am a newbie on this group. I came here to see if there
was discussion on AAT (I've read 3 books by Elaine Morgan). The post I
replied hinted at that and, then, I posted my message, to see what
happened. Now I am happy to see all the posts about it.
AAT, in my opinion, has a lot of different reasons (the fat layer, tears
with salt, bipedalism, hair loss, etc) pointing all in the same
direction. What I would like to know is if there is a solid argument
against. Or if there is a more consistent argument in favour of
another theory.
Thanks in advance
Manuel Correa
--
I cannot judge my work while I am doing it. I have to do as
painters do, stand back and view it from a distance, but not too
great a distance. How great? Guess. Blaise Pascal
Jim McGinn
> As for Oreopithecus its bipedalism may have been much
> more postural than an efficient or reliable means of locomotion.
Very good point. In fact there are good reasons why it is reasonable to
assume that Oreopithecus's, as well as Apith's, bipedal posture was postural
and not locomotory. And these reasons have to do with the ecological
concept of optimization. It's one thing to say that chimps could easily
evolve into a species that has a tendency to habitually take a bipedal
stance while stationery. It's quite another thing altogether to say that
chimps could easily evolve into an animal that is optimized for walking or
running. The most obvious complication that is associated with this is that
if our earliest chimpanzee-like ancestors started to become optimized for
walking or running bipedally they would, by necessity, have much of their
strength shifted to their lower bodies thus making them less able to defend
against predators which they surely could not outrun.
If you look at it from an ecological standpoint there really is only one
reasonable conclusion. Bipedalism had to have evolved in situational
factors by which they could remain stationery so that their bodies could
continue to be optimized for climbing trees which was still their main
strategy against predators. This indicates a territorial, communal
lifestyle rather than the transient lifestyle--a notion which, it seems, has
more to do with fulfilling the preconcieved notions of the hunter-gatherer
myth than it does science.
Jim
marc verhaegen
Manuel Ritto Correa heeft geschreven in bericht
>Let me tell you I am a newbie on this group. I came here to see if there
>was discussion on AAT (I've read 3 books by Elaine Morgan). The post I
>replied hinted at that and, then, I posted my message, to see what
>happened. Now I am happy to see all the posts about it.
>AAT, in my opinion, has a lot of different reasons (the fat layer, tears
>with salt, bipedalism, hair loss, etc) pointing all in the same
>direction. What I would like to know is if there is a solid argument
>against. Or if there is a more consistent argument in favour of
>another theory. Thanks in advance Manuel Correa
Hi Manuel. The theory that we had ancestors that spent a lot of time in
water (wading & diving) has no solid argument against it. Only the
educational=savanna biases of some traditional paleoanthropologists (luckily
less & less). Any "newbie" with some common sense immediately sees that AAT
in one form or another must be correct. You can find Elaine at
http://www.onelist.com/community/AAT
Marc Verhaegen
http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
http://www.flash.net/~hydra9/marcaat.html
http://www.infres.enst.fr/confs/evolang/actes/_actes74.html
e
<marc.ve...@village.uunet.be> =====
Hey there -
Some folks experience a profound anxiety if they can't
grab onto a quick explanation. The AAT starts from a
dogmatic conclusion and selects each element of "proof"
to support their desired result. They ignore any pieces
which inconveniently throw a wrench into the works....
You are being courted and welcomed by the main advertising
agent. As far as using a solid scientific method of
reasoning the AAT falls short. Do you wonder why you
will not find these ideas well represented in serious
anthropology texts....?
Can you look at the pieces with your naked eyes or
do you feel better with rose colored specs?
Filtering doesn't produce good science.....
but maybe good art or religion is made that way.
ejudy
>
>>. What I would like to know is if there is a solid argument
>>against. Or if there is a more consistent argument in favour of
>>another theory. Thanks in advance Manuel Correa
>
>
>Hi Manuel. The theory that we had ancestors that spent a lot of time in
>water (wading & diving) has no solid argument against it. Only the
>educational=savanna biases of some traditional paleoanthropologists (luckily
>less & less). Any "newbie" with some common sense immediately sees that AAT
>in one form or another must be correct. You can find Elaine at
>http://www.onelist.com/community/AAT
>
>Marc Verhaegen
>
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marc verhaegen
e heeft geschreven in bericht <3AC8...@MailAndNews.com>...
>The AAT starts from a dogmatic conclusion.
To the contrary, we use ALL the evidence instead of giving biased
interpretations of fossil evidence as the savanna believers do, as you can
see here:
African ape and human evolution
(Proceedings Symposium Oslo 2000 "Marine fat and human Health")
Marc Verhaegen & Stephen Munro
We attempt to reconstruct the evolutionary history of apes and humans by
using the available biomolecular, geological, fossil and comparative data.
Our hypothesis is that wading-climbing hominids in coastal forests near the
Arabian peninsula evolved during the Ice Ages into wading-diving Homo
species on the tidal flats, lagoons and reefs along the Indian Ocean.1
The Old World higher primates originated in Africa, where they split into
monkeys and apes more than 30 Ma (million years ago). Typically, apes differ
from monkeys in having larger bodies, no tail, and by climbing arms
overhead. These features seem to have been present in some early African ape
fossils about 20-16 Ma (large size and probably tail loss in Proconsul,
arm-hanging and more vertical body in Morotopithecus).
It is believed that about 25 Ma the African-Arabian and Eurasian continents
made contact, forming and altering the coastlines of the Tethys and later
the Mediterranean Sea.2 It is not certain on which continent the apes split
into the lesser apes (gibbons, Asia) and the great apes (Asia and Africa).
Between about 16 and 6 Ma, most great-ape fossils are found in southern
Eurasia (dryopithecines). DNA and fossil data suggest the great apes split
into pongids (orangutans, Asia) and hominids 14 ± 4 Ma, the hominids split
into gorillas and humans-chimps 8 ± 3 Ma, and humans and chimpanzees split 6
± 2 Ma. Pongid fossils are found in Asia after about 10 Ma (sivapithecines),
and hominid fossils in Africa after about 6 Ma (australopithecines).
Presumably the ancestors of the australopithecines, African apes and humans
lived in Africa-Arabia at the time when they split into gorillas and
humans-chimps (8 ± 3 Ma).
We argue the early apes led a climbing-wading lifestyle in forest swamps,
where they became bigger (for gravitational and thermo-regulatory reasons),
lost their tail (which may have hindered locomotion and caused heat loss in
water), and became arm-hangers and more bipedal (for wading and grasping
branches or fruits above the water). Proboscis monkeys cross shallow
stretches of water between mangrove trees on two legs, and lowland gorillas
go wading for reed sedges and aquatic herbs in forest swamps.3 Perhaps in a
similar way, only more frequently, our apelike ancestors waded and perhaps
swam in swamp, gallery, mangrove or flooded forests. A population of
wading-climbing great-apes in the coastal forests between Eurasia and Africa
may have given rise to the Eurasian dryopithecines and later the African
australopithecines.
Early dryopithecine fossils have been found in marine near-shore sands along
the Tethys Sea (Heliopithecus ca. 17 Ma at the Persian Gulf, and
Austriacopithecus ca. 14 Ma in what are now the Alps).2 Dental micro-wear
suggests their diet might have resembled that of the fruit-eating
orangutans, but included more hard foods (Griphopithecus ca. 14 Ma in
Anatolia).4 In later dryopithecines, the eastern branch probably belonged to
the pongids (e.g. Sivapithecus, India),2 whereas European fossils are
sometimes considered to have had more hominid features. Thin-enamelled apes
with more vertical body postures seem to have dwelt in swamp forests: the
arm-hanging Dryopithecus might have fed mostly on tree leaves (ca. 12-10 Ma,
western-central Europe),2 whereas the presumably bipedally wading
Oreopithecus probably had aquatic herbs in its diet (ca. 9-7 Ma, island of
Tuscany-Sardinia).5 More hominid-like dryopithecines, like later
australopithecine and Homo species, had much thicker enamel and possibly
lived in less forested milieus (Graecopithecus and Ankarapithecus ca. 10-8
Ma, Greece and Anatolia).
Arguably, the australopithecines left the Red Sea coasts and followed the
African Rift Valley, where their fossils (ca. 6-1 Ma) have been found in
gallery forests, lakeside grasslands, riverside reedbeds, papyrus swamps,
montane forests and shallow lagoons.1 Their postcranial anatomy suggests
they might have waded regularly on two legs and perhaps also knuckle-walked
(e.g. bipedal footprints, knuckle-walking features of wrists, very long arms
in later fossils), and spent part of their time in the trees (e.g. curved
phalanges, upward oriented shoulder joints, toeing-in of feet). Their
dentition suggests the diet included fruits and nuts, aquatic herbs and
sedges, and hard foods, possibly reed or bamboo (e.g. broad cheekteeth, very
thick enamel, polished micro-wear).1
Meanwhile, human ancestors might have remained near the coasts. Tool use and
thick tooth enamel are typical features of hominids, capuchin monkeys, and
sea otters. Mangrove capuchins crack nuts with stones and use shells to
remove oysters from mangrove trunks.6 Sea otters have flat cheekteeth
resembling those of australopithecines, and open shells with stones.7
Chimpanzees, with somewhat thinner molar enamel, hammer hard-shelled nuts
with stones. Conceivably, the human-chimp ancestors some 6 Ma used hard
objects to open the shells of fruits, nuts and oysters in coastal forests.
During the Ice Ages, the climate cooled and dried, coastal forests shrank,
and sea levels dropped. Our tool-using and bipedally wading ancestors were
ideally preadapted to colonise the newly formed tidal flats, and estuaries,
embayed lagoons, reef back-channels, near-shore islands, beaches and coral
reefs on the continental shelves along the Indian Ocean. They lost their
climbing adaptations, and might have beach-combed for coconuts or turtles,
and waded and dived for shellfish, fish and crayfish. Humans have much more
efficient diving and breath-hold capabilities than nonhuman primates, which
could explain the development of voluntary sound production and speech.8 It
was at the seashore, we believe, that our ancestors acquired their huge
brain, voluntary speech, stone tool technologies and extreme dexterity, as
well as an external nose, naked skin, thicker subcutaneous fat, linear
swimming-build and long wading-legs.8
Indeed, Homo fossils, as opposed to australopithecines, are typically found
near shellfish (e.g. Chiwondo, Chemeron, Nariokotome, Zhoukoudian, Boxgrove,
Terra Amata, Gesher Benot Ya’aqov, Rabat, Hopefield, Gibraltar). Although
sea-level rises and the actions of waves and tides have drastically reduced
the chances of discovering hominid fossils at sea beaches, Homo erectus
remains have been discovered amid shellfish, barnacles and corals, from the
Mojokerto skull at Java about 1.8 Ma,9 to the Acheulean tools of Eritrea
about 0.1 Ma.10 Stone tools discovered on Flores suggest that, already 0.8
Ma, Homo erectus crossed the 19-kilometer-wide water barrier known as
Wallace’s Line. The ‘fast’ dispersal of Homo erectus from Java to the Cape
and England most likely occurred along the seashores.
From the sea shores, different Homo sidebranches could have migrated up
rivers into the interiors of Africa and Eurasia. Initially restricted to the
edges of rivers and lakes, human populations such as neandertals and modern
humans might have later moved to areas further from permanent water.
[1] Verhaegen, M. and Puech, P.-F. (2000) Hominid lifestyle and diet
reconsidered: paleo-environmental and comparative data, Human Evol. 15,
151-162
[2] Else, J. G. and Lee, P. C., eds (1986) Primate Evolution, Cambridge
Univ. Press
[3] Doran, D. M. and McNeilage, A. (1997) Gorilla ecology and behavior,
Evol. Anthrop. 6, 120-130
[4] King, T., Aiello, L. C. and Andrews, P. (1998) Dental microwear of
Griphopithecus alpani, J. human Evol. 36, 3-31
[5] Rook, L. et al. (1999) Oreopithecus was a bipedal ape after all, Proc.
Natl. Acad. Sci. USA 96, 8795-9
[6] Fernandes, M. E. B. (1991) Tool use and predation of oysters by the
tufted capuchin in brackish water mangrove swamp, Primates 32, 529-531
[7] Walker, A. (1981) Diet and teeth – dietary hypotheses and human
evolution, Phil. Trans. R. Soc. London B 292, 57-64
[8] Morgan, E. (1997) The aquatic ape hypothesis – the most credible theory
of human evolution, Souvenir, London
[9] Von Koenigswald, G.H.R. (1958) Begenungen mit dem Vormenschen,
Diederichs, Köln
[10] Walter, R. C. et al. (2000) Early human occupation of the Red Sea coast
of Eritrea during the last interglacial, Nature 405, 65-69
Ejudy, FYI:
Further literature in files at http://www.onelist.com/community/AAT
Ghent symposium 1999 http://allserv.rug.ac.be/~mvaneech/Symposium.html
Eritrean tools ca. 0.125 Ma http://www.exn.ca/hominids/outofafrica.cfm
Kate Douglas New Scientist http://www.newscientist.com/nlf/1125/taking.html
Phillip Tobias on AAT http://archive.outthere.co.za/98/dec98/disp1dec.html
Marc
marc verhaegen
Neurocop heeft geschreven in bericht
>> Sorry, yes, I misread something I believe. But how can buoyancy help
>> understand bipedalism? Marc
>
>I don't believe that bouyancy was the sole or even main evolutionary
>determinant of bipedalism. I believe that for pure terrestrial locomotor
>efficiency in vertebrates quadrupedalism is better. The main reason
>bipedalism developed in humans was that it freed the forelimbs for some
>function that more than compensated for bipedalism's lower efficiency.
>Manipulative ability, especially tool use, drove the evolutionary
>compromise.
I'm not so sure: chimps use their hands more often than kangaroos.
>The think I like about the wading scenario is that it provides a mechanism
>to facilitate the switch to an upright posture. It is physically demanding
>for quadrupeds or even brachiators to sustain an upright posture for any
>length of time. Most apes that I have observed at the zoo (sorry, I'm an
>urban anthropologist at best) tend to sit on their butts when using their
>hands for any serious manipulation.
>
>Wading at least chest deep would provide a brachiator (which I prefer to
>think of as a facultative biped) the bouyancy to use the hands for extended
>manipulation without having to expend as much energy as a brachiator that
>tried the same feat on terra firma.
Because the water supports the body, you mean?
(Brachiator = fast arm-swining as in gibbons & spider monkeys. IMO our
ancestors were only suspensory once: climbing vertically, in the trees above
the swamp.
>The wading scenario serves the same function of facilitating an anatomic
>transformation that an enzyme serves in catalyzing a chemical reaction.
>That, in a nutshell, is what I like about your hypothesis. Nick
Capozzoli
Yes, wading catalyzes the transition from arboreal to humanlike bipedality.
It's more complicated though IMO: other data suggest it was from arboreal
(all pirmates) to climbing+wading to wading+diving (more linear build,
longer legs than in apith) to humanlike walking. IMO the transition from
above-branch (Old World monkeys) to below-branch locomotion (hominoids) was
catalyzed by a climbing+wading phase in the early "apes". If they spent a
lot of time in swamp forests, that would explain their increase in body
size, their tail loss (would have hndered locomotion in water, and caused
heat loss), and their climbing arms overhead. IOW, IMO the early hominoids
lived in coastal forests or so. First gibbons split off & returned to the
canopy, reduced their body size (but retained a longer gestation period) &
became acrobatic brachiators. Then the great apes split into pongids &
hominids. The pongids became cautious branch-hangers (orangs), the hominids
became waders-climbers: more bipedalism for wading, suspensory climbing.
Then the hominids split into Gorilla & Homo-Pan. With the Plio-Pleistocene
cooling the other hominoids became less wading & more forest animals. Homo
OTOH reduced his climbing adaptations & developed his wading-diving
adaptations (breath-hold diving, more linear build, longer wading-legs...) &
spread along the Indian Ocean to Java.
marc verhaegen
Gerrit Hanenburg heeft geschreven in bericht
<3a96360c...@news.nl.uu.net>...
>"marc verhaegen" <marc.ve...@village.uunet.be> wrote:
>
>>Bipedalism as a product of wading is no curiosity at all. To the contrary,
>>the most-bipedal non-human primate is exactly the one that wades most
>>frequently: the proboscis monkey (mangrove swamp).
>
>Now you are being dishonest.
Calling names = tactics of losers.
Neurocop
> >Wading at least chest deep would provide a brachiator (which I prefer to
> >think of as a facultative biped) the bouyancy to use the hands for
extended
> >manipulation without having to expend as much energy as a brachiator that
> >tried the same feat on terra firma.
>
> Because the water supports the body, you mean?
Yes. That is exactly what I mean.
> Yes, wading catalyzes the transition from arboreal to humanlike
bipedality.
> It's more complicated though IMO: other data suggest it was from arboreal
> (all pirmates) to climbing+wading to wading+diving (more linear build,
> longer legs than in apith) to humanlike walking. IMO the transition from
> above-branch (Old World monkeys) to below-branch locomotion (hominoids)
was
> catalyzed by a climbing+wading phase in the early "apes". If they spent a
> lot of time in swamp forests, that would explain their increase in body
> size, their tail loss (would have hndered locomotion in water, and caused
> heat loss), and their climbing arms overhead. IOW, IMO the early hominoids
> lived in coastal forests or so. First gibbons split off & returned to the
> canopy, reduced their body size (but retained a longer gestation period) &
> became acrobatic brachiators. Then the great apes split into pongids &
> hominids. The pongids became cautious branch-hangers (orangs), the
hominids
> became waders-climbers: more bipedalism for wading, suspensory climbing.
> Then the hominids split into Gorilla & Homo-Pan. With the Plio-Pleistocene
> cooling the other hominoids became less wading & more forest animals. Homo
> OTOH reduced his climbing adaptations & developed his wading-diving
> adaptations (breath-hold diving, more linear build, longer wading-legs...)
&
> spread along the Indian Ocean to Java.
>
> Marc Verhaegen
All of those things are plausible.To repeat myself, the compelling argument
about wading is that it provides buoyancy to help support the body on the
legs and frees the upper extremities for manipulation. That is the thing I
liked about your original post.
marc verhaegen
Neurocop heeft geschreven in bericht
>>Yes, wading catalyzes the transition from arboreal to humanlike
bipedality.
>>It's more complicated though IMO: other data suggest it was from arboreal
>>(all pirmates) to climbing+wading to wading+diving (more linear build,
>>longer legs than in apith) to humanlike walking. IMO the transition from
>>above-branch (Old World monkeys) to below-branch locomotion (hominoids)
>>was catalyzed by a climbing+wading phase in the early "apes". If they
spent
>>a lot of time in swamp forests, that would explain their increase in body
>>size, their tail loss (would have hindered locomotion in water, and caused
>>heat loss), and their climbing arms overhead. IOW, IMO the early hominoids
>>lived in coastal forests or so. First gibbons split off & returned to the
>>canopy, reduced their body size (but retained a longer gestation period) &
>>became acrobatic brachiators. Then the great apes split into pongids &
>>hominids. The pongids became cautious branch-hangers (orangs), the
>>hominids became waders-climbers: more bipedalism for wading, suspensory
>>climbing. Then the hominids split into Gorilla & Homo-Pan. With the Plio-
>>Pleistocene cooling the other hominoids became less wading & more forest
>>animals. Homo OTOH reduced his climbing adaptations & developed his
>>wading-diving adaptations (breath-hold diving, more linear build, longer
>>wading-legs...) & spread along the Indian Ocean to Java. Marc Verhaegen
>
>All of those things are plausible.To repeat myself, the compelling argument
>about wading is that it provides buoyancy to help support the body on the
>legs and frees the upper extremities for manipulation. That is the thing I
>liked about your original post.
Wading alone isn't enough: in fact the buoyancy argument would prefer a
horizontal posture in water (then a greater part of the body is supported by
the water). Most wading mammals are quadrupedal: tapirs, babirusas. But
primates already have a tendency to stand more erect (to climb, to grasp
fruits overhead...).
Marc
Michael Clark
>
> Manuel Ritto Correa heeft geschreven in bericht
> <3A964C77...@civil.ist.utl.pt>...
>
>
> Hi Manuel. The theory that we had ancestors that spent a lot of time in
> water (wading & diving) has no solid argument against it. Only the
> educational=savanna biases of some traditional paleoanthropologists (luckily
> less & less). Any "newbie" with some common sense immediately sees that AAT
> in one form or another must be correct. You can find Elaine at
> http://www.onelist.com/community/AAT
>
> Marc Verhaegen
> http://allserv.rug.ac.be/~mvaneech/Verhaegen.html
> http://www.flash.net/~hydra9/marcaat.html
> http://www.infres.enst.fr/confs/evolang/actes/_actes74.html
Hi Manuel. The theory that we had ancestors that spent a
lot of time in
water (wading & diving) has no solid argument in favor of
it. By all means, check out the links provided by "Dr."
Verhaegen. If you have a rational mind, you should have no
trouble separating fact from fantasy.
While you're here, check out posts by Gerrit Hanenburg in
reply to Verhaegen.
--
Michael Clark
mcl...@skypoint.com
tomo...@yahoo.com
marc verhaegen
Michael Clark heeft geschreven in bericht
<3A97EDFC...@skypoint.com>...
>>Hi Manuel. The theory that we had ancestors that spent a lot of
>>time in water (wading & diving) has no solid argument against it.
>>Only the educational=savanna biases of some traditional
>>paleoanthropologists (luckily less & less). Any "newbie" with
>>some common sense immediately sees that AAT in one form
>>or another must be correct. You can find Elaine at
>>http://www.onelist.com/community/AAT .....
>
>Hi Manuel. The theory that we had ancestors that
>spent alot of time in water (wading & diving) has no
>solid argument in favor of it.
A child can see what the savanna believers with their blind spots can't:
that the solid comparative evidence suggests we had ancestors that spent a
lot of time in water wading & diving.
> By all means, check out the links provided by "Dr."
>Verhaegen. If you have a rational mind, you should have no
>trouble separating fact from fantasy.
>While you're here, check out posts by Gerrit Hanenburg in
>reply to Verhaegen. --
>Michael Clark
Yes, do that. The combination of all evidence (fossil, comparative, DNA,
geological) supports the following (provisional) view of hominoid evolution:
A scenario of ape & human evolution
Marc Verhaegen & Stephen Munro
We attempt to reconstruct the evolutionary history of apes and humans by
using the available biomolecular, geological, fossil and comparative data.
Our hypothesis is that wading-climbing hominids in coastal forests near the
Arabian peninsula evolved during the Ice Ages into wading-diving Homo
species on the tidal flats, reefs and lagoons along the Indian Ocean.1
Further literature in files at http://www.onelist.com/community/AAT
Ghent symposium 1999 http://allserv.rug.ac.be/~mvaneech/Symposium.html
Eritrean tools ca. 0.125 Ma http://www.exn.ca/hominids/outofafrica.cfm
Kate Douglas New Scientist http://www.newscientist.com/nlf/1125/taking.html
Phillip Tobias on AAT http://archive.outthere.co.za/98/dec98/disp1dec.html
I haven't seen yet any serious objection to this scenario, not from
Hanenburg & certainly not from Clark.
:-)
Marc
Michael Clark
>
[snip excreta]
>
> I haven't seen yet any serious objection to this scenario, not from
> Hanenburg & certainly not from Clark.
>
> :-)
>
> Marc
You haven't seen it from me, of course. I don't think
you're worth it. If you haven't seen it from Gerrit, you
need to get your eyes checked.
Neurocop
> Wading alone isn't enough: in fact the buoyancy argument would prefer a
> horizontal posture in water (then a greater part of the body is supported
by
> the water). Most wading mammals are quadrupedal: tapirs, babirusas. But
> primates already have a tendency to stand more erect (to climb, to grasp
> fruits overhead...).
>
> Marc
For an obligate quadruped what you say about wading favoring a horizontal
posture is true. We are not talking about obligate quadrupeds. We are
talking about brachiators, who tend to sit on terra firma to use their
hands, or to plant themselves on the two hindlimbs and one forelimb, while
using the other forelimb to manipulate.
In these animals, wading to chest height in water would tend to promote the
upright posture. This argument, Marc, seems pretty compelling. I'm surprised
that you seem not to appreciate it.
da...@ecn.ab.ca
marc verhaegen (marc.ve...@village.uunet.be) wrote:
<snip>
: During the Ice Ages, the climate cooled and dried, coastal forests
: shrank, and sea levels dropped.
The extent of coastal forests may have been reduced on what is land
today, but isn't it more reasonable to suppose that coastal forests
migrated with the coastline as sea levels dropped?
Coastal forests may have increased in area, given that wide expanses
of poorly-drained continental shelf were newly exposed for colonisation
by coastal forest vegetation as the sea regressed.
As for climate drying, that's a generalisation: local results varied.
There are many instances of pluvial lakes appearing, or increasing in
size, during glacial periods, in what are now arid deserts (American
southwest, Sahara, central Asia, e.g.).
: Our tool-using and bipedally wading ancestors were ideally preadapted to
: colonise the newly formed tidal flats, and estuaries,
: embayed lagoons, reef back-channels, near-shore islands, beaches and
: coral reefs on the continental shelves along the Indian Ocean.
<snip>
Estuaries are landscape features created by _rising_ sea levels.
They are submerged river valleys, valleys that developed at times of
low sea level.
During times of low sea level, sediments accumulated in river valleys
are eroded because the stream gradient is steeper and the stream's energy
is increased (the Nile valley, for instance, became a narrow canyon).
If the newly-excavated streambed is resistant, then rapids and
waterfalls develop.
What were formerly coastal and deltaic areas are incised by the river
as they are exposed by lowering sea levels. A river valley develops where
before there was none (or perhaps where there was a submarine canyon, if
the slope of the shelf is steep enough).
The sides of the newly-formed valley, now exposed to sub-aerial
erosion, are eaten away and the valley broadens.
When sea level rises again, these valleys are submerged, stream energy
decreases and now competes with tidal influences, and sedimentation
occurs, leaving broad shallow, flat-floored channels at the mouths or
rivers, i.e. estuaries.
The idea of "newly formed" estuaries at times of lowering sea levels
is an oxymoron.
Also, coral reefs and lagoons take a long time to develop, and
near-shore islands are likely to be scarcer as continental shelves are
not noted for the type of bathymetric ("topographic") features that would
become islands, because "they were all too flat", to quote the man who
wanted the fish license for his pet 'alibut, Eric (which seems strangely
appropriate, given that character's insistence on a heterodox version of
reality).
Pondering the probable drastic reduction in habitat suitable for wading
ancestors during the onset of a glacial episode,
Daryl Krupa
marc verhaegen
da...@ecn.ab.ca heeft geschreven in bericht <3a9b...@ecn.ab.ca>...
> A couple of minor quibbles . . .
>marc verhaegen (marc.ve...@village.uunet.be) wrote:
.....
>: During the Ice Ages, the climate cooled and dried, coastal forests
>: shrank, and sea levels dropped.
>
>The extent of coastal forests may have been reduced on what is land
>today, but isn't it more reasonable to suppose that coastal forests
>migrated with the coastline as sea levels dropped?
Yes, that's certainly possible. We have not enough information on how the
coasts during the glaciations looked like, but AFAIK it's assumed that
during most the Pleistocene, most forests (inlcuding the coastal forests)
shrank drastically. In any case, Homo lost most of its climbing adaptations,
which suggests they lived in tree-poor milieus (or else: their diving
adaptations hindered their climbing adaptations). No doubt near water
(physiology). If the coasts were still forested, our ancestors may have
lived more on the fringing reefs (only coconut trees, which they could
earlily climb with longer legs? could provide freshwater & safe place to
sleep against felids).
>Coastal forests may have increased in area, given that wide expanses
>of poorly-drained continental shelf were newly exposed for colonisation
>by coastal forest vegetation as the sea regressed.
> As for climate drying, that's a generalisation: local results varied.
Yes. Our scenario is of course much too schematic.
>There are many instances of pluvial lakes appearing, or increasing in
>size, during glacial periods, in what are now arid deserts (American
>southwest, Sahara, central Asia, e.g.).
Certainly a possibility, but erectus had a very dense skeleton (typical of
marine bottom-diving species), "fast" dispersal to Java (probably along
coasts), is found amid corals & barnacles & marine diatoms & shells (Java).
The only problem with a coastal life is our freshwater requirements.
>: Our tool-using and bipedally wading ancestors were ideally preadapted to
>: colonise the newly formed tidal flats, and estuaries,
>: embayed lagoons, reef back-channels, near-shore islands, beaches and
>: coral reefs on the continental shelves along the Indian Ocean.
>
> Estuaries are landscape features created by _rising_ sea levels.
Thanks for the information. Well, the Pleistocene had alternating
glaciations & interglacials. These dropping & rising sea levels (changing
lifestyles) could have been responsible for the fast evolution & large brain
size (intelligence) of Homo.
>They are submerged river valleys, valleys that developed at times of
>low sea level.
> During times of low sea level, sediments accumulated in river valleys
>are eroded because the stream gradient is steeper and the stream's energy
>is increased (the Nile valley, for instance, became a narrow canyon).
> If the newly-excavated streambed is resistant, then rapids and
>waterfalls develop.
> What were formerly coastal and deltaic areas are incised by the river
>as they are exposed by lowering sea levels. A river valley develops where
>before there was none (or perhaps where there was a submarine canyon, if
>the slope of the shelf is steep enough).
> The sides of the newly-formed valley, now exposed to sub-aerial
>erosion, are eaten away and the valley broadens.
> When sea level rises again, these valleys are submerged, stream energy
>decreases and now competes with tidal influences, and sedimentation
>occurs, leaving broad shallow, flat-floored channels at the mouths or
>rivers, i.e. estuaries.
> The idea of "newly formed" estuaries at times of lowering sea levels
>is an oxymoron.
Thanks a lot, Daryl, we'll have to our view.
> Also, coral reefs and lagoons take a long time to develop,
I read somewhere coral reefs can grow a few decimeters per year?
>and
>near-shore islands are likely to be scarcer as continental shelves are
>not noted for the type of bathymetric ("topographic") features that would
>become islands, because "they were all too flat", to quote the man who
>wanted the fish license for his pet 'alibut, Eric (which seems strangely
>appropriate, given that character's insistence on a heterodox version of
>reality).
The cooling & warming periods probably had a great influence upon our
ancestors' life. We thought that during the cold periods, they lived more
near the coasts, and during interglacials, they followed the rivers inland.
Whart do you think?
>Pondering the probable drastic reduction in habitat suitable for wading
>ancestors during the onset of a glacial episode,
>Daryl Krupa
Wading + diving.
Daryl, several considerations suggest that our ancestors once relied heavily
on shellfish (bottom-diving, tool use, thick enamel...). Do you have
information on the possible abundance of mussels/oysters etc. during colder
periods? where they more/less abundant? How did the coasts look like in
colder/warmer periods of the Pleistocene?
Thanks a lot.
Marc
>
marc verhaegen
Rich Travsky heeft geschreven in bericht
>> >Usually ignored by AA types is the small amount of time spent in such
>> wading
>> >behaviors. Hardly compelling. (Marc is fond of a Nat Geo article showing
a
>> >gorilla
>> >in water. He never mentions that the photographer waited 3 weeks (I
believe
>> it
>> >was) to get the shot.
>>
>> As usual you miss the point. The wading gorillas show the
>> possibility & how a semi-aquatic life could have evolved.
>
>My dog goes in the water too, but how many dogs have a semi aquatic
>lifestyle? Ditto for any other animal that can wade once in a while...
Again you miss the point. Your dog is a primate? & eats aquatic herbaceous
vegetation, like the gorillas?
http://www.logres.net/dawn/apeart.html
marc verhaegen
Neurocop heeft geschreven in bericht
>
>"marc verhaegen" <marc.ve...@village.uunet.be> wrote in message
>news:3a9978f2$0$4493$73be...@news.be.uu.net...
>>Wading alone isn't enough: in fact the buoyancy argument would prefer a
>>horizontal posture in water (then a greater part of the body is supported
by
>>the water). Most wading mammals are quadrupedal: tapirs, babirusas. But
>>primates already have a tendency to stand more erect (to climb, to grasp
>>fruits overhead...). Marc
>
>For an obligate quadruped what you say about wading favoring a horizontal
>posture is true. We are not talking about obligate quadrupeds. We are
>talking about brachiators,
Arm-hangers you mean? Brachiators are gibbons & spider monkeys (fast moving
arms overhead).
Well, why did hominoids evolve arm-hanging? what made them so different from
monkeys? The colobine monkey that wades most frequently on 2 legs & also
climbs most frequently arms overhead is the proboscis monkey, which lives in
mangrove forests. IMO a wading+climbing lifestyle (in swamp or mangrove
forests) could explain why hominoids became much bigger than monkeys, why
they lost their tails (would have hindered locomotion in water), why they
became more erect & why they began climbing arms overhead. This
common-hominoid locomotion (aquarboreal) could explain the lifestyles of the
living hominoids: the fast-moving gibbons (+ secondary reduction of weight
for fast brachiation), the slow suspensory orangs, the knuckle-walking
African apes & the wading+diving adaptations in Homo.
>who tend to sit on terra firma to use their
>hands, or to plant themselves on the two hindlimbs and one forelimb, while
>using the other forelimb to manipulate.
>
>In these animals, wading to chest height in water would tend to promote the
>upright posture. This argument, Marc, seems pretty compelling. I'm
surprised
>that you seem not to appreciate it.
I probably misunderstood... :-)
Marc
Neurocop
> Well, why did hominoids evolve arm-hanging? what made them so different
from
> monkeys? The colobine monkey that wades most frequently on 2 legs & also
> climbs most frequently arms overhead is the proboscis monkey, which lives
in
> mangrove forests. IMO a wading+climbing lifestyle (in swamp or mangrove
> forests) could explain why hominoids became much bigger than monkeys, why
> they lost their tails (would have hindered locomotion in water), why they
> became more erect & why they began climbing arms overhead. This
> common-hominoid locomotion (aquarboreal) could explain the lifestyles of
the
> living hominoids: the fast-moving gibbons (+ secondary reduction of weight
> for fast brachiation), the slow suspensory orangs, the knuckle-walking
Yes. That seems logical. The important thing is that we assume the
arborial/brachiator habit developed first and that these "facultative"
bipeds waded into the water. Their brachiating physiques then allowed them
to become more consistent bipeds. As you say, there is little that would
prompt an obligate quadruped to assume an upright posture while wading.
Nick Capozzoli
Manuel Ritto Correa
>
> Manuel Ritto Correa heeft geschreven in bericht
> <3A964C77...@civil.ist.utl.pt>...
>
> >Let me tell you I am a newbie on this group. I came here to see if there
> >was discussion on AAT (I've read 3 books by Elaine Morgan). The post I
> >replied hinted at that and, then, I posted my message, to see what
> >happened. Now I am happy to see all the posts about it.
> >AAT, in my opinion, has a lot of different reasons (the fat layer, tears
> >with salt, bipedalism, hair loss, etc) pointing all in the same
> >direction. What I would like to know is if there is a solid argument
> >against. Or if there is a more consistent argument in favour of
> >another theory. Thanks in advance Manuel Correa
>
> Hi Manuel. The theory that we had ancestors that spent a lot of time in
> water (wading & diving) has no solid argument against it. Only the
> educational=savanna biases of some traditional paleoanthropologists (luckily
> less & less). Any "newbie" with some common sense immediately sees that AAT
> in one form or another must be correct. You can find Elaine at
> http://www.onelist.com/community/AAT
Thanks for all the information.
I see there is a somewhat heated discussion about this...
But, I agree with you, AAT seems to be unavoidably to be part of the
true. Of course with no direct proof one has to deal with some
hypothetical scenarios. But, as far as I know can also be said about the
whole savanna scenario.
Manuel Correa
--
The pure and simple truth is rarely pure and never simple. Oscar Wilde
Gerrit Hanenburg
>>>Bipedalism as a product of wading is no curiosity at all. To the contrary,
>>>the most-bipedal non-human primate is exactly the one that wades most
>>>frequently: the proboscis monkey (mangrove swamp).
>>
>>Now you are being dishonest.
>
>Calling names = tactics of losers.
You snipped the reason why I consider you dishonest. I assume you did
that because you have no response to it?
Anyway, how would you call someone who deliberately presents a
statement as fact in order to promote a hypothesis while he/she knows
that the truth value of the statement is unknown?
Gerrit
David Timpe
.
| There are many instances of pluvial lakes appearing, or increasing in
| size, during glacial periods, in what are now arid deserts (American
| southwest, Sahara, central Asia, e.g.).
You can add the Bolivian Altiplano to that list:
http://www.sciencedaily.com/releases/2001/02/010208073917.htm
--
Dave Timpe
davetimpe at new dot rr dot com
marc verhaegen
Gerrit Hanenburg heeft geschreven in bericht
>"marc verhaegen" <marc.ve...@village.uunet.be> wrote:
>
>>>>Bipedalism as a product of wading is no curiosity at all. To the
contrary,
>>>>the most-bipedal non-human primate is exactly the one that wades most
>>>>frequently: the proboscis monkey (mangrove swamp).
>>>
>>>Now you are being dishonest.
>>
>>Calling names = tactics of losers.
>
>You snipped the reason why I consider you dishonest. I assume you did
>that because you have no response to it?
Because I had not expected such childish behaviour from you.
>Anyway, how would you call someone who deliberately presents a
>statement as fact in order to promote a hypothesis while he/she knows
>that the truth value of the statement is unknown? Gerrit
Whatever you call, it did not apply to me.
Richard Wagler
marc verhaegen wrote:
The source of the confusion is this. You state that nasalis is
the most bipedal of monkeys. When asked for a reference
you cite Elaine Morgan who notes the difficulties of doing
field studies on these animals. You then repeat the first
statement.
Can you spell E - X - A - S - P - E - R - A - T - I - O - N ?
Rick Wagler
marc verhaegen
Manuel Ritto Correa heeft geschreven in bericht
>> >Let me tell you I am a newbie on this group. I came here to see if there
>> >was discussion on AAT (I've read 3 books by Elaine Morgan). The post I
>> >replied hinted at that and, then, I posted my message, to see what
>> >happened. Now I am happy to see all the posts about it.
>> >AAT, in my opinion, has a lot of different reasons (the fat layer, tears
>> >with salt, bipedalism, hair loss, etc) pointing all in the same
>> >direction. What I would like to know is if there is a solid argument
>> >against. Or if there is a more consistent argument in favour of
>> >another theory. Thanks in advance Manuel Correa
>>
>> Hi Manuel. The theory that we had ancestors that spent a lot of time in
>> water (wading & diving) has no solid argument against it. Only the
>> educational=savanna biases of some traditional paleoanthropologists
>> (luckily less & less). Any "newbie" with some common sense
>> immediately sees that AAT in one form or another must be correct.
>> You can find Elaine at http://www.onelist.com/community/AAT
>
>Thanks for all the information.
>I see there is a somewhat heated discussion about this...
(it used to be a lot hotter in the past...)
>But, I agree with you, AAT seems to be unavoidably to be part of the
>true. Of course with no direct proof one has to deal with some
>hypothetical scenarios.
Depends on what you call "direct". IMO, the comparative evidence is a lot
more direct than the fossil evidence. The comparative evidence is about
ourselves. The fossil evidence is about the fossils.
> But, as far as I know can also be said about the
>whole savanna scenario. Manuel Correa
Manuel Ritto Correa
>
> Manuel Ritto Correa heeft geschreven in bericht
>
> >
> >Thanks for all the information.
> >I see there is a somewhat heated discussion about this...
>
> (it used to be a lot hotter in the past...)
:-)
> >But, I agree with you, AAT seems to be unavoidably to be part of the
> >true. Of course with no direct proof one has to deal with some
> >hypothetical scenarios.
>
> Depends on what you call "direct". IMO, the comparative evidence is a lot
> more direct than the fossil evidence. The comparative evidence is about
> ourselves. The fossil evidence is about the fossils.
Yes, that is of course the most appealing of the AAT. When I say there
is no "direct evidence" I mean we weren't *there* to observe the aquatic
behaviour. But, of course, that applies to all the evolution process
and, by the way, also to all the cosmological theories.
In science, and also in history, we have to make educated guesses on the
basis of what we *do* know. I agree with you that the fossil record is
just another piece in the puzzle.
Manuel Correa
--
All stable processes we shall predict. All unstable processes we
shall control. John von Neumann
Gerrit Hanenburg
>>You snipped the reason why I consider you dishonest. I assume you did
>>that because you have no response to it?
>
>Because I had not expected such childish behaviour from you.
Since when is it childish to charge someone of something if you have
clear evidence that the suspect is guilty (calling names is childish,
but I didn't call him names, Your Honor).
>>Anyway, how would you call someone who deliberately presents a
>>statement as fact in order to promote a hypothesis while he/she knows
>>that the truth value of the statement is unknown? Gerrit
>
>Whatever you call, it did not apply to me.
Would a thief admit that he stole something?
Gerrit
marc verhaegen
Richard Wagler heeft geschreven in bericht <3A9D5831...@home.com>...
>Can you spell E - X - A - S - P - E - R - A - T - I - O - N ?
No
marc verhaegen
Manuel Ritto Correa heeft geschreven in bericht
>> >But, I agree with you, AAT seems to be unavoidably to be part of the
>> >true. Of course with no direct proof one has to deal with some
>> >hypothetical scenarios.
>>
>> Depends on what you call "direct". IMO, the comparative evidence is a lot
>> more direct than the fossil evidence. The comparative evidence is about
>> ourselves. The fossil evidence is about the fossils.
>
>Yes, that is of course the most appealing of the AAT. When I say there
>is no "direct evidence" I mean we weren't *there* to observe the aquatic
>behaviour.
OK, sorry I misunderstood.
>But, of course, that applies to all the evolution process
>and, by the way, also to all the cosmological theories.
>In science, and also in history, we have to make educated guesses on the
>basis of what we *do* know. I agree with you that the fossil record is
>just another piece in the puzzle. Manuel Correa
I fully agree.
Marc
Robert Keeter
writes. . . .
Marc,
If the 'rillas were wading around in water up to their armpits, I agree that
it would lessen the loads on the pelvis and legs. It would ALLOW an animal
that did not have the underlying structure and muscles for pure bipedal
travel to possibly shuffle along on two legs. Wading waist deep for a
gorilla (remember where the mass is on his frame!), just would not do it.
You have to have displacement to get bouyancy and the big displacement items
on a gorilla are not down in his legs but rather up in the torso. Evolution
advances into areas where the current "machinery" does not fit. If gorillas
(or some pre-human ancestor) took up deep wading for whateber purpose, that
would hardly push the evolution of the mechanical parts that would support
dry bipedalism.
As for the above, to do much good, our wading proto-hominid would have to be
wading in fairly deep water to get any meaningful benefit from bouyance (and
then we could debate whether that advantage could have led to dry land
bipedalism!). How deep were the gorillas in the documentary that you are
citing?
Now if we still are hassling over the possibility of a human evolutionary
path that went along the line of "tree ape", "ground ape", "water ape",
ground hominid, H.sapiens (with maybe a couple of jumps left out for brevity
sake!), does the analogy still hold. Look at other groups that have a more
or less "adapted" wader. If we eliminate the thorougly discounted image of
an apatasaur strolling amongst the river reeds, we have the moose and wading
birds. Know of any more? (Hippo's I think more of as a "swimmer" as with
croc's, turtles, etc.) Now Im not talking about species that CAN wade (most
can!), but rather those that wade to a degree that evolution has started
modifying their physiology to enhance their abilities. What I see is LONG
legs developing on creatures that already had quite functional legs. I dont
see quadrupeds becoming bipedal, just growing longer legs. Look at all of
the wading birds (who have had plenty of time to "evolve" into the niche!).
All that happened is that they got longer legs!!!!
Still think that you are asking a lot in order to justify the theory! ;-)
Regards
bk
pete
> I dont see quadrupeds becoming bipedal, just growing longer legs.
> Look at all of the wading birds
> (who have had plenty of time to "evolve" into the niche!).
> All that happened is that they got longer legs!!!!
You do realize that wading birds were always bipedal, right?
What more would you have the waders do, stand on one leg?
Hey, wait a minute ..., they do!
--
pete
marc verhaegen
Neurocop heeft geschreven in bericht
>>Well, why did hominoids evolve arm-hanging? what made them so different
>>from monkeys? The colobine monkey that wades most frequently on 2 legs &
>>also climbs most frequently arms overhead is the proboscis monkey, which
lives
>>in mangrove forests. IMO a wading+climbing lifestyle (in swamp or mangrove
>>forests) could explain why hominoids became much bigger than monkeys, why
>>they lost their tails (would have hindered locomotion in water), why they
>>became more erect & why they began climbing arms overhead. This
>>common-hominoid locomotion (aquarboreal) could explain the lifestyles of
>>the living hominoids: the fast-moving gibbons (+ secondary reduction of
weight
>>for fast brachiation), the slow suspensory orangs, the knuckle-walking ...
>
>Yes. That seems logical. The important thing is that we assume the
>arborial/brachiator habit developed first and that these "facultative"
>bipeds waded into the water.
Colobus monkeys also run on 2 legs through shallow water, but they're no
brachiators.
IMO, wading-climbing early hominoids explain why hominoids became
below-branch movers (as opposed to all other catarrhines). I see it this
way: the hominoids at the time of the ape-cercopith split (ie, at a time
when they were still above-branch movers) started more frequent wading. This
explains their large size, their tail loss, they tendency to erectness, &
their climbing arms overhead. No other milieu can explain IMO why hominoids
differ in these respects from monkeys.
>Their brachiating physiques then allowed them
>to become more consistent bipeds. As you say, there is little that would
>prompt an obligate quadruped to assume an upright posture while wading.
>Nick Capozzoli
Yes, but arboreals are less obligate quadrupeds than terrestrials.
Robert Keeter
wrote on 3/2/01 6:38 AM:
Oh yea, I did sort of get on to the idea that BIRDS were bipedal when they
started wading! ;-) Aside from Bullwinkle of "Rocky and " I dont know of a
single moose, even though quite well adapted to wading, to have developed
any bipedal tendencies! ;-)
As for true bipedalism, I can think of very, very few. You can start with
Man (and his immediate ancestors), Birds, (add in therapods, if you think
that there is really a difference!), the ornithisucians, and . . . . . . . .
. well, uh. . . . . . . . . .
Care to add in a few more? ;-)
Regards
bk
marc verhaegen
Robert Keeter heeft geschreven in bericht ...
>After a long work-induced vacation from the AAT theory debate, Bob Keeter
>writes. . . .
>
>Marc,
>
>If the 'rillas were wading around in water up to their armpits, I agree
that
>it would lessen the loads on the pelvis and legs. It would ALLOW an animal
>that did not have the underlying structure and muscles for pure bipedal
>travel to possibly shuffle along on two legs. Wading waist deep for a
>gorilla (remember where the mass is on his frame!), just would not do it.
I woudn't know (too theoretical to be true?), & I'm not sure what you want
to imply. I guess forest swamps can have different depths. Gorillas sit or
knuckle-walk in knee-deep places, stand or wade bipedally in waist-deep
places, & probably stand & swim in armpit-deep places (gorillas in zoos are
good swimmers, some sort of breast stroke).
Well, I look at the wading gorillas in 2 ways:
- They show that a wading-climbing lifestyle is possible. I'm not saying our
ancestors lived in exactly the same way.
- IMO the early hominoids & hominids were aquarboreal. The wading gorillas
are a rudiment of that.
>You have to have displacement to get bouyancy and the big displacement
items
>on a gorilla are not down in his legs but rather up in the torso.
Evolution
>advances into areas where the current "machinery" does not fit. If
gorillas
>(or some pre-human ancestor) took up deep wading for whatever purpose, that
>would hardly push the evolution of the mechanical parts that would support
>dry bipedalism.
Sorry, I don't see what you mean: too theoretical IMO.
- I don't think they waded in neck-deep water. Why should they? It's easier
to swim there.
- As for buoyancy: there are some misunderstandings here, I think. Our
seafood collecting ancestors didn't need to get buoyancy: the food was near
the bottom!
My standpoint is simple: the combination fo the available evidence
(comparative-DNA-geological-fossil...) suggests the early hominids spent a
lot of time in trees+water, probably at one time or another coastal forests,
but exactly how their environment & locomotion looked like, I don't know
(Mio-Pliocene milieus were probably different from today: several °C
warmer). The hominid LCA ca.8-6 Ma seems to have waded bipedally & perhaps
sometimes on its knuckles, probably swam at the surface, but did not dive
much, & climbed arms overhead in trees. The lifestyles of the living
hominids are easily derivable from this, eg, gorillas more knuckle-walking,
humans more bipedal, bonobos more climbing.
>As for the above, to do much good, our wading proto-hominid would have to
be
>wading in fairly deep water to get any meaningful benefit from bouyance
(and
>then we could debate whether that advantage could have led to dry land
>bipedalism!). How deep were the gorillas in the documentary that you are
>citing?
They waded bipedally & on their knuckles, sat (eating), played (children
sometimes on their parents), grasped branches overhead (eg, to come out of
the swamp), ... 50 cm to more than 1 meter?
>Now if we still are hassling over the possibility of a human evolutionary
>path that went along the line of "tree ape", "ground ape", "water ape",
>ground hominid, H.sapiens (with maybe a couple of jumps left out for
brevity
>sake!), does the analogy still hold. Look at other groups that have a more
>or less "adapted" wader. If we eliminate the thorougly discounted image of
>an apatasaur strolling amongst the river reeds, we have the moose and
wading
>birds. Know of any more? (Hippo's I think more of as a "swimmer" as with
(AFAIK hippos are no good swimmers: they walk & stand on the bottom)
>croc's, turtles, etc.) Now Im not talking about species that CAN wade
(most
>can!), but rather those that wade to a degree that evolution has started
>modifying their physiology to enhance their abilities. What I see is LONG
>legs developing on creatures that already had quite functional legs. I
dont
>see quadrupeds becoming bipedal, just growing longer legs. Look at all of
>the wading birds (who have had plenty of time to "evolve" into the niche!).
>All that happened is that they got longer legs!!!!
RK, I think you haven't read any of my papers? AFAICS human bipedalism
results from climbing + wading & swimming + diving + walking: from
monkey-like arboreal to aquarboreal to seaside (& no trees) to land. Of
course our legs have always been functional - what else?? Very long legs are
probably late: not in apes or apiths or monkeys, only in Homo. Very long
legs in birds can be for wading or for running (eg, flamingoes & ostriches).
>Still think that you are asking a lot in order to justify the theory! ;-)
Regards
?? To the contrary: my view is extremely practical: compare with what other
animals do.
Robert Keeter
marc.ve...@village.uunet.be wrote on 3/2/01 3:58 PM:
SNip. . . . .
>>
>> If the 'rillas were wading around in water up to their armpits, I agree that
>> it would lessen the loads on the pelvis and legs. It would ALLOW an animal
>> that did not have the underlying structure and muscles for pure bipedal
>> travel to possibly shuffle along on two legs. Wading waist deep for a
>> gorilla (remember where the mass is on his frame!), just would not do it.
>
> I woudn't know (too theoretical to be true?), & I'm not sure what you want
> to imply. I guess forest swamps can have different depths. Gorillas sit or
> knuckle-walk in knee-deep places, stand or wade bipedally in waist-deep
> places, & probably stand & swim in armpit-deep places (gorillas in zoos are
> good swimmers, some sort of breast stroke).
>
I've also seen a gorilla "swim" in the moat around a gorilla compound. Not
exactly graceful but definitely effective,. . . . . . . . as long as the
only objective was to splash around in the water, ankle deep! ;-)
http://education.wsu.edu/99Fall/Workspace/TL/450/Preservice/Spring_99/Mammal
s/gorilla.htm
Watch out for that wrap, but its really pretty rare to find an academic make
such a bold statement as you find at this URL! ;-)
The discussion on depth is actually a bit pertinent. In order to gain any
advantage in supporting the gorilla's trunk, a significant portion of the
trunk would need to be underwater (Archimedes Principle I think its called!)
http://www.free4all.com/encyclopedia/articles/00687.html
To get a pound of weight off of the hip (and a big gorilla can go up to
about 550-600 lbs I think), you have to displace a pound of water. to get
any siginificant portion of that weight off and actually facilitate a
bipedal gait, you have got to displace a lot of water. Legs and hips just
dont displace much water, Plus, any weight that is "taken up" by bouyancy is
mostly in the legs, leaving the hips still to support the massive weight of
the gorilla's torso. Not the most advantageous of "enabling functions"! ;-)
Mammalian flesh and bone is very marginally lighter than water, IF you toss
in the lungs. This is why most humans and other mammals can at least float.
On the other hand, a human male (who is a bit less dense than a gorilla,
hopefully on a couple of counts! ;-) ), without a lot of "spare tire", can
usually exhale while floating and simply sink! He sinks when his body mass,
including the partially deflated lungs, is heavier than the same volume of
water. (Think of the abdomen being "sucked in" by the diaphram during the
exhale.)
I concede that the wading gorilla might gain some small advantage in the
water, but it would be very small.
Snippage. . . . .
>
>> You have to have displacement to get bouyancy and the big displacement
>> items
>> on a gorilla are not down in his legs but rather up in the torso.
>> Evolution
>> advances into areas where the current "machinery" does not fit. If
>> gorillas
>> (or some pre-human ancestor) took up deep wading for whatever purpose, that
>> would hardly push the evolution of the mechanical parts that would support
>> dry bipedalism.
>
> Sorry, I don't see what you mean: too theoretical IMO.
The bouyant properties of partially submerging a body in water is not
terribly theoretical. Boats do it! Human swimmers do it(at least when
swimming on the surface)! and gorillas dont do it! ;-)
> - I don't think they waded in neck-deep water. Why should they? It's easier
> to swim there.
Gorillas dont swim. . . . . Also found some "ancient history" on wading
gorillas at:
http://www.anatomy.usyd.edu.au/danny/anthropology/sci.anthropology.paleo/arc
hive/july-1995/0017.html
> - As for buoyancy: there are some misunderstandings here, I think. Our
> seafood collecting ancestors didn't need to get buoyancy: the food was near
> the bottom!
>
Does that mean that they had to reach down with their hands and grab that
seafood off of the bottom? In other words, the IDEAL posture for knuckle
walking?
> My standpoint is simple: the combination fo the available evidence
> (comparative-DNA-geological-fossil...) suggests the early hominids spent a
> lot of time in trees+water, probably at one time or another coastal forests,
> but exactly how their environment & locomotion looked like, I don't know
> (Mio-Pliocene milieus were probably different from today: several °C
> warmer). The hominid LCA ca.8-6 Ma seems to have waded bipedally & perhaps
> sometimes on its knuckles, probably swam at the surface, but did not dive
> much, & climbed arms overhead in trees. The lifestyles of the living
> hominids are easily derivable from this, eg, gorillas more knuckle-walking,
> humans more bipedal, bonobos more climbing.
>
Ummm. 'Scuse please. EXACTLY what piece of EVIDENCE, not conjecture, not
theory not "feasibility" but EVIDENCE is there for an "aquatic" ape or
proto-human?
>
>
>> As for the above, to do much good, our wading proto-hominid would have to
>> be
>> wading in fairly deep water to get any meaningful benefit from bouyance
>> (and
>> then we could debate whether that advantage could have led to dry land
>> bipedalism!). How deep were the gorillas in the documentary that you are
>> citing?
>
> They waded bipedally & on their knuckles, sat (eating), played (children
> sometimes on their parents), grasped branches overhead (eg, to come out of
> the swamp), ... 50 cm to more than 1 meter?
>
>> Now if we still are hassling over the possibility of a human evolutionary
>> path that went along the line of "tree ape", "ground ape", "water ape",
>> ground hominid, H.sapiens (with maybe a couple of jumps left out for
>> brevity
>> sake!), does the analogy still hold. Look at other groups that have a more
>> or less "adapted" wader. If we eliminate the thorougly discounted image of
>> an apatasaur strolling amongst the river reeds, we have the moose and
>> wading
>> birds. Know of any more? (Hippo's I think more of as a "swimmer" as with
>
> (AFAIK hippos are no good swimmers: they walk & stand on the bottom)
>
Guess its that ole engineering mindset on my part. . . . . . . AND a trip to
the San Diego Zoo. Does eyeball visual, empirically gathered evidence count
for anything as to hippo's swimming ability? ;-)
If not, . . . . . . .
http://www.sddt.com/features/balboapark/zoo/hippo.html
http://www.toledozoo.org/html/hippoquarium.htm
http://www.buschgardens.org/animal_bytes/hippopotamusab.html
and
Brust, Beth W. Zoobooks: Hippos. San Diego: Wildlife Education, Ltd., 1989.
MacDonald, David (ed.). The Encyclopedia of Mammals. Vol. 2. London: George,
Allen & Unwin, 1984.
Parker, Sybil P. (ed.). Grzimek's Encyclopedia of Mammals. Vol. 5. New York:
McGraw-Hill, 1990.
Redmond, Ian. "Africa's Four-Legged Whale," Wildlife Conservation.Jan.-Feb.
1991, pp. 60-69
for some hardcopy references. These MIGHT shed a different light on the
aquatic habits (and abilities) of hippos! OR we could arrange to watch some
of those old 1950's Tarzan and Jungle Jim movies! ;-))
snippage. . . . . .
>
> RK, I think you haven't read any of my papers? AFAICS human bipedalism
> results from climbing + wading & swimming + diving + walking: from
> monkey-like arboreal to aquarboreal to seaside (& no trees) to land. Of
> course our legs have always been functional - what else?? Very long legs are
> probably late: not in apes or apiths or monkeys, only in Homo. Very long
> legs in birds can be for wading or for running (eg, flamingoes & ostriches).
>
Nope. Read your papers (at least the ones on the web). Just dont really
understand the focus on aquatic human ancestors as a FACT and not as an
interesting conjecture (without some direct evidence, the word "theory"
probably is a bit strong!).
>> Still think that you are asking a lot in order to justify the theory! ;-)
> Regards
>
>
> ?? To the contrary: my view is extremely practical: compare with what other
> animals do.
>
I did. They dont compare well at all.
Sorry!
Regards
bk
da...@ecn.ab.ca
Before I can answer intelligently, you're going to have to fill in the
missing bits of your own response.
<snip>
: da...@ecn.ab.ca heeft geschreven in bericht <3a9b...@ecn.ab.ca>...
: >There are many instances of pluvial lakes appearing, or increasing in
: >size, during glacial periods, in what are now arid deserts (American
: >southwest, Sahara, central Asia, e.g.).
marc verhaegen (marc.ve...@village.uunet.be) wrote:
: Certainly a possibility, but erectus had a very dense skeleton (typical of
: marine bottom-diving species), "fast" dispersal to Java (probably along
: coasts), is found amid corals & barnacles & marine diatoms & shells (Java).
This completely baffles me.
The way your argument is presented, you seem to have refuted the
former existence of, e.g., Pluvial Lake Bonneville (around Great Salt
Lake in Utah, U.S.A.) and its associated widespread lacustrine sediments
that date back to the Last Glacial Maximum (LGM), relict beaches,
presently dry outlet channel near the head of the Snake River, etc.,
by invoking a low degree of porosity in fossil hominid bones found in a
completely different environment on the other side of an ocean!
And in case that wasn't enough evidence against the fact of wetter
conditions in some areas in glacial times, you bring up hominid migration
rates between Africa and Southeast Asia.! (By this time, I am reeling from
the stupefying effects of your "one-two" pugilistic assault.)
Then the knockout blow: the evidence is associated with _marine_
organisms! (I am rolling on the floor, gasping for breath, as I try to
deal with the nigh-unfathomable implications of this connexion.)
So there we have it:
Glacial-time climates were cold and dry, hence no pluvial lakes, because
erectus had a dense skull,
set a World Record in the Intercontinental Dash, and
was buried at sea when he crossed the finish line.
And yet, magnanimous in victory, you reach out to give me a hand:
: The only problem with a coastal life is our freshwater requirements.
So, you very graciously allow that if pluvial lakes _had_ existed,
then erectus would have rushed over immediately and begun wading therein,
but as no erectus fossils have been found during construction for the next
Winter Olympics, there cannot have been a lake there in glacial times.
Thank you, no need to explain, it's all so clear, now . . .
. . . just as clear as the rest of your theory . . .
[But wait, there's more . . . ]
: I read somewhere coral reefs can grow a few decimeters per year?
Why are you asking me?
I don't keep track of what you read; ask your mother.
: >and
: >near-shore islands are likely to be scarcer as continental shelves are
: >not noted for the type of bathymetric ("topographic") features that would
: >become islands, because "they were all too flat", to quote the man who
: >wanted the fish license for his pet 'alibut, Eric (which seems strangely
: >appropriate, given that character's insistence on a heterodox version of
: >reality).
: The cooling & warming periods probably had a great influence upon our
: ancestors' life. We thought that during the cold periods, they lived more
: near the coasts, and during interglacials, they followed the rivers inland.
: Whart do you think?
Ask over in alt.fan.monty-python as to the meaning of the pythonesque
references in my paragraph above, then you'll know what I think of your
idea.
: >Pondering the probable drastic reduction in habitat suitable for wading
: >ancestors during the onset of a glacial episode,
: >Daryl Krupa
: Wading + diving.
Yes, of course, I see . . . now how can I counter that concise logical
rapier-thin riposte?
I know -
Flapping + gliding.
There, let's see you try to wave _that_ one away!
: Daryl, several considerations suggest that our ancestors once relied heavily
: on shellfish (bottom-diving, tool use, thick enamel...). Do you have
: information on the possible abundance of mussels/oysters etc. during colder
: periods? where they more/less abundant?
This is my theory:
The mussels and oysters were very, very, rare on the glaciers, much, much
more abundant in the oceans, and rare again in the volcanos.
: How did the coasts look like in
: colder/warmer periods of the Pleistocene?
They were moistly wettish, occasionally damp, sometimes virtually
hydrated.
: Thanks a lot.
No thanks necessary . . .
: >
Daryl Krupa, Silly Party Candidate
Neurocop
Of course you are correct, Marc. I misused the term, "brachiator" to include
primates with a branch-hanging/climbing/swinging habit, and not just those
who use a brachiating form of ground ambulation. This was my error.
However, I stick by my comments about how such animals would behave in
water, which is different from how obligate quadrupeds would behave.
Nick Capozzoli
Neurocop
"Robert Keeter" <rke...@earthlink.net> wrote in message
news:B6C56F11.1273%rke...@earthlink.net...
> in article 3A9F86...@mindspring.com, pete at pfi...@mindspring.com
> wrote on 3/2/01 6:38 AM:
>
> > Robert Keeter wrote:
> >> I dont see quadrupeds becoming bipedal, just growing longer legs.
> >> Look at all of the wading birds
> >> (who have had plenty of time to "evolve" into the niche!).
> >> All that happened is that they got longer legs!!!!
> >
> > You do realize that wading birds were always bipedal, right?
> > What more would you have the waders do, stand on one leg?
> > Hey, wait a minute ..., they do!
This bird argument is quite old. It goes back to Aristotle, who defined man
as "a biped without feathers" (as opposed to a chicken...)
A better definition of man would be "a biped without feathers that uses
tools." The key is that birds use there forelimbs for a quite different
purpose that humans. Then we must consider the Kangaroo, which is certainly
bipedal, but doesn't use its forelimbs for tool-manipulation. That also
applies to T. rex and some other dinosaurs.
Various animals evoleved a bipedal lifestyle. Only humans evolved that
lifestyle in association with bimanual manipulation of tools, for which the
forelimbs became specialized.
Nick Capozzoli
marc verhaegen
Neurocop heeft geschreven in bericht
>Of course you are correct, Marc. I misused the term, "brachiator" to
include
>primates with a branch-hanging/climbing/swinging habit, and not just those
>who use a brachiating form of ground ambulation. This was my error.
>
>However, I stick by my comments about how such animals would behave in
>water, which is different from how obligate quadrupeds would behave.
>Nick Capozzoli
OK, though IMO it's the reverse:
- not brachiating>biped.wading,
- rather arboreal>biped.wading>suspensory.
Marc
marc verhaegen
Neurocop heeft geschreven in bericht
>Various animals evolved a bipedal lifestyle. Only humans evolved that
>lifestyle in association with bimanual manipulation of tools, for which the
>forelimbs became specialized. Nick Capozzoli
Yes, the association in Homo is clear. But did humanlike bipedality evolve
for using tools? I don't think so: as you say, the correlation between tool
use & bipedality in animals is not high. IMO, tool use & bipedality must be
explained apart:
- (stone) tool use in mammals: sea otters, capuchins, chimps (none of these
is bipedal BTW): for opening hard-shelled foods (nuts, oysters...),
- humanlike bipedality: unique: no direct comparative evidence, IMO it's
only the combination of all available evidence that brings us further here:
IMO our present-day locomotion evolved like this:
0) climbing (monkey-like),
1) wade+climb(+swim): apith-like bipedality (short legs, bent knees & hips;
curved phalanges for climbing...),
2) wade+dive(+walk): Homo dispersal along Indian Ocean: more linear build,
longer legs,
3) +-exclusive walking: sapiens: basicranial flexion.
This division (1-2-3) seems to be supported by the anatomy, eg, of the
pelvis:
MARCHAL F 2000 "A new morphometric analysis of the hominid pelvic bone" JHE
38:347-365: "...possible to detect 2 levels of difference. The first
separates Australopithecus from Homo and could be seen as reflecting
locomotor differences between both genera. The second splits both Homo
erectus and Neanderthal from modern human pelvic bones... "
marc verhaegen
Robert Keeter heeft geschreven in bericht ...
(snipped on buoyancy etc. - thanks for the websites)
>>>You have to have displacement to get bouyancy and the
>>>big displacement items on a gorilla are not down in
>>>his legs but rather up in the torso. Evolution advances into
>>>areas where the current "machinery" does not fit. If
>>>gorillas (or some pre-human ancestor) took up deep
>>>wading for whatever purpose, that would hardly push
>>>the evolution of the mechanical parts that would support
>>>dry bipedalism.
>>
>> Sorry, I don't see what you mean: too theoretical IMO.
>
>The bouyant properties of partially submerging a body in water is not
>terribly theoretical. Boats do it! Human swimmers do it(at least when
>swimming on the surface)! and gorillas dont do it! ;-)
Sorry, rephrase: I don't see the relevance here.
>> - I don't think they waded in neck-deep water.
>>Why should they? It's easier to swim there.
>
>Gorillas dont swim.
They love to do, at least in zoos on hot days: R.R.Golding 1972 "A gorilla &
chimp.exhibit at the Univ. of Ibidan Zoo" Internatl.Zoo Yb.12:71-76.
>. . . . Also found some "ancient history" on wading gorillas at:
>http://www.anatomy.usyd.edu.au/danny/anthropology/sci.anthropology.paleo/ar
chive/july-1995/0017.html
Thanks. Gorillas seem to knuckle-walk in knee-deep water & wade in
waist-deep water.
>> - As for buoyancy: there are some misunderstandings here, I think. Our
>> seafood collecting ancestors didn't need to get buoyancy: the food was
near
>> the bottom!
>
>Does that mean that they had to reach down with their hands and grab that
>seafood off of the bottom? In other words, the IDEAL posture for knuckle
>walking?
? I don't think our ancestors were ever committed knuckle-walkers:
http://allserv.rug.ac.be/~mvaneech/Fil/Verhaegen_Human_Evolution.html.
Rather, I see our Homo ancestors near the Indian Ocean wading bipedally &
dipping & diving for bottom foods - not knuckle-walking there.
>> My standpoint is simple: the combination fo the available evidence
>> (comparative-DNA-geological-fossil...) suggests the early hominids spent
a
>> lot of time in trees+water, probably at one time or another coastal
forests,
>> but exactly how their environment & locomotion looked like, I don't know
>> (Mio-Pliocene milieus were probably different from today: several °C
>> warmer). The hominid LCA ca.8-6 Ma seems to have waded bipedally &
perhaps
>> sometimes on its knuckles, probably swam at the surface, but did not dive
>> much, & climbed arms overhead in trees. The lifestyles of the living
>> hominids are easily derivable from this, eg, gorillas more
knuckle-walking,
>> humans more bipedal, bonobos more climbing.
>
>Ummm. 'Scuse please. EXACTLY what piece of EVIDENCE, not conjecture, not
>theory not "feasibility" but EVIDENCE is there for an "aquatic" ape or
>proto-human?
Why should I know, RK? Perhaps you could ask Elaine Morgan?
For our view, see, eg, http://www.logres.net/dawn/apeart.html
Note we're dealing here with historical sciences: reconstruct what happened.
>>>As for the above, to do much good, our wading proto-
>>>hominid would have to be wading in fairly deep water to
>>>get any meaningful benefit from bouyance (and then we
>>>could debate whether that advantage could have led to
>>>dry land bipedalism!). How deep were the gorillas in
>>>the documentary that you are citing?
>>
>>They waded bipedally & on their knuckles, sat (eating), played
>>(children sometimes on their parents), grasped branches overhead
>>(eg, to come out of the swamp), ... 50 cm to more than 1 meter?
.....
>> RK, I think you haven't read any of my papers? AFAICS human bipedalism
>> results from climbing + wading & swimming + diving + walking: from
>> monkey-like arboreal to aquarboreal to seaside (& no trees) to land. Of
>> course our legs have always been functional - what else?? Very long legs
are
>> probably late: not in apes or apiths or monkeys, only in Homo. Very long
>> legs in birds can be for wading or for running (eg, flamingoes &
ostriches).
>
>Nope. Read your papers (at least the ones on the web). Just dont really
>understand the focus on aquatic human ancestors as a FACT and not as an
>interesting conjecture (without some direct evidence, the word "theory"
>probably is a bit strong!).
I have no doubt semi-aquatic ancestors are a FACT.
No other way you can explain linear build & SC fat etc.
What do you call "direct evidence"? IMO, the comparative evidence is a lot
more direct (much more complete & concerning our ancestors) than the fossil
evidence (fragmentary & says only something on the fossils).
>>> Still think that you are asking a lot in order to justify the theory!
;-)
>>
>> ?? To the contrary: my view is extremely practical: compare with what
other
>> animals do.
>
>I did. They dont compare well at all.
I agree humans are unique. But so are all species. But when you compare
human features with those of apes & savanna mammals & arboreal mammals &
marine mammals & semi-aquatic mammals, it's clear that we never had savanna
ancestors, & it's very likely that we never had fully aquatic ancestors, &
it's clear that we had semi-aquatic ancestors.
From 1993 "Aquatic versus savanna: comparative and paleo-environmental
evidence" Nutrition and Health 9:165-191:
"More typical of (semi)aquatic than of savanna or arboreal mammals are:
nakedness, superficial fat, elaborate sebaceous glands, salty “tears”,
multipapillary kidneys, flipper-like feet, broad hands, barrel-shaped
thorax, volitional breath control, poor olfaction, very long childhood and
very high longevity. A few other human features might also be typical of
aquatics (Morgan, 1982, 89; Verhaegen, 1987, 1991 a,c; Rhys Evans, 1992):
proneness to bronchial constriction, and to occlusion of the auditory canal
in swimmers, extensive superficial venous networks, and extensive, valveless
vertebral venous networks.
A second group of features, while characteristic of (semi)aquatic species,
may sometimes be found in arboreal mammals (often in apes), but these also
are absent in savanna mammals: rectal temperature around 37°C, very small
diurnal temperature fluctuations, proneness to dehydration, thermo-active
eccrine glands, ventro-ventral copulation, great angle between spine and
bind limbs, broadened thorax, very large brain, and very long lactation.
Very atypical of savanna mammals are: high water needs, low drinking
capacity, maximal urine concentration of c.1400 mOsm/1, relatively long
first and fifth digital rays of feet and hands, tool use, well-developed
dexterity and vocality.
A few features, when compared to other mammals, do not allow clear
conclusions: bipedality, descended larynx, external nose, milk composition,
and long gestation.
Several human features are absent in Cetacea, Sirenia and most Pinnipedia:
large paranasal sinuses, moderate ear size, inferior position of the foramen
magnum, broad sternal bones, long clavicles, long arms, very long legs,
scrotal testes. All of these are found in (some or all) other primates, but
only the long limbs and the descended testes (and perhaps the large sinuses)
are normally seen in savanna mammals.
On balance then, if we must choose between an aquatic and a savanna
scenario, the choice is easy: not one single feature distinguishing the
savanna mammals is found in humans (relative independence of drinking water
and of water-containing nourishment, high tolerance of radiation heat, very
high diurnal body temperatures and daily temperature fluctuations, very
large external ears, slender build, high velocity, etc.).
In Table 3, the numerical score for “fully aquatic” is not far short of that
for “semi-aquatic”, but in view of our long scalp, axillar and pubic hair,
abundant skin glands (eccrine, sebaceous, and axillar apocrine), scrotal
testes, intermediate ear size, pneumatised skull, inferior foramen magnum
position, broad shoulders, short lumbar spine, non-rudimentary pelvis, very
long legs, tool use, and return to the land, it is unlikely that there ever
existed a fully aquatic stage..."
Robert Keeter
thal...@ix.netcom.com wrote on 3/3/01 1:31 AM:
Snippage. . . . . . .
>
> This bird argument is quite old. It goes back to Aristotle, who defined man
> as "a biped without feathers" (as opposed to a chicken...)
>
> A better definition of man would be "a biped without feathers that uses
> tools." The key is that birds use there forelimbs for a quite different
> purpose that humans. Then we must consider the Kangaroo, which is certainly
> bipedal, but doesn't use its forelimbs for tool-manipulation. That also
> applies to T. rex and some other dinosaurs.
>
> Various animals evoleved a bipedal lifestyle. Only humans evolved that
> lifestyle in association with bimanual manipulation of tools, for which the
> forelimbs became specialized.
>
1. I seem to CONTINUALLY forget about those bloody blokes from down under!
(Of course I might have been fishing for one as well, since I was hammered
on that bipedal critter in a different thread!!!) ;-))
2. Maybe I should phrase it a bit differently! Are there ANY bipeds that
have evolved (with any kind of HARD evidence!), in a fairly direct and
immediate path (i.e. << 10my of time) from wading predecessors? OK. What if
we toss out the "constricting" time limit? Didnt think so! ;-)
Regards
bk
Tim Tyler
: The colobine monkey that wades most frequently on 2 legs & also
: climbs most frequently arms overhead is the proboscis monkey, which lives in
: mangrove forests. IMO a wading+climbing lifestyle (in swamp or mangrove
: forests) could explain why hominoids became much bigger than monkeys, why
: they lost their tails (would have hindered locomotion in water), why they
: became more erect & why they began climbing arms overhead. [...]
Why primates lost their tails:
Unless you are proposing an aquatic ancestor for all primates it
seems obvious that AAT has absolutely nothing to do with tail loss.
The logic behind tals equating to additional drag seems dubious anyway -
many other semi-aquatic mammals have kept their tails.
Could tail-loss be something to do with the relatively large size of
the common ancestor?
Was the ancestor without the tail not spending much time in the trees?
Informed speculation welcomed.
--
__________
|im |yler t...@cryogen.com Home page: http://alife.co.uk/tim/
Tim Tyler
: Are there ANY bipeds that have evolved (with any kind of HARD
: evidence!), in a fairly direct and immediate path (i.e. << 10my of
: time) from wading predecessors? OK. What if we toss out the
: "constricting" time limit? Didnt think so! ;-)
Practicalls all animals wade when they want to cross watery patches
badly enough.
Your question consequently reduces to: are there any bipedal animals
who once went about on all fours?
The answer is "yes": penguins, kangaroos, T-tex, man - all the bipedal
animals in fact.
I expect some of them got their eyes higher above the ground, and
could run a bit faster as a consequence of their bipedality (as
well as an ability to keep their nose above the water) - but these
are advantages that man experienced as well.
--
__________ http://alife.co.uk/ http://mandala.co.uk/
|im |yler t...@cryogen.com http://hex.org.uk/ http://atoms.org.uk/
marc verhaegen
Tim Tyler heeft geschreven in bericht ...
>marc verhaegen <marc.ve...@village.uunet.be> wrote:
>
>: The colobine monkey that wades most frequently on 2 legs & also
>: climbs most frequently arms overhead is the proboscis monkey, which lives
in
>: mangrove forests. IMO a wading+climbing lifestyle (in swamp or mangrove
>: forests) could explain why hominoids became much bigger than monkeys, why
>: they lost their tails (would have hindered locomotion in water), why they
>: became more erect & why they began climbing arms overhead. [...]
>
>Why primates lost their tails:
>Unless you are proposing an aquatic ancestor for all primates it
>seems obvious that AAT has absolutely nothing to do with tail loss.
I'm proposing a wading-climbing ancestor (swamp forests) for the hominoids
(tail-less), not for most other primates.
>The logic behind tails equating to additional drag seems dubious anyway -
>many other semi-aquatic mammals have kept their tails.
Yes, for locomotion in water. But a monkey-like tail is of no use for
propulsion in a wading primate.
>Could tail-loss be something to do with the relatively large size of
>the common ancestor?
Certainly possible: large mammals tend to have rel.shorter tails. Note that
spider monkeys have long (in fact, grasping) tails, & the equally large
gibbons no tail at all. (Gibbons also have longer gestation periods than
equally large monkeys, which oculd suggest their ancestors were larger in
the past.)
>Was the ancestor without the tail not spending much time in the trees?
>Informed speculation welcomed.
I guess they slept in trees & collected fruits & nuts in trees, but also
spent a lot of time in swamps (eg, for collecting aquatic herbs or weeds as
lowland gorillas sometimes do, or for collecting mangrove oysters as
capuchins sometimes do (thick enamel, tool use)).
Bob Keeter
Not sure that "informed" is the right term, but I'll go for some
speculation.
Seems to me that there are only a few "reasons" for a tail in land
animals. First it is for balance, for example a cheetah and an
ornithisician both have a relatively large tail apparently used to
ballance out the body, with the cheetah, when its at speed, with the
dino so that it can manage a bipedal gait. If you look at other
animals the tail is prehensile, oppossum and monkeys, normally
indicating at least some climbing. Finally, grazing animals use their
tails as flyswatters. In most aquatic animals, either the tail has
been reduced to a festigal little stump (turtles and seals) or has
evolved into the primary propulsion system (whales, manatees, croc's,
etc)
All that said, I have a feeling that once man's ancestors moved down
from the trees (at least as primary residences!) the benefit of a tail
certainly started to disappear. If you believe that some of the larger
arboreal primates are on the main trunk of the family tree (i.e.
orangutans, etc), maybe the tail went away even sooner. (In the orang's
case might simply be that the animal is too large and heavy to get much
real advantage from a prehensile tail.
I think Id have to vote for size as the "driver". Early man did not
need a tail to "balance" a cantilevered bipedal stance. He did not
need a tail to counterbalance as he made 40mph turns in pursuit of a
gazelle, and he had two free limbs to swat flies! ;-0 Can you imagine
a full sized male chimp hanging from a branch with a prehensile tail
(didnt think so!) ;-))
Jaguars are about the most aquatic cat that I can think of, and I have
to suppose that they have been in a semi-aquatic lifestyle for a lot
longer than any human ancestor had time to be! Yet, they still have a
nice tail and a quadrupedal gait.
Neurocop
"Tim Tyler" <t...@cryogen.com> wrote in message news:GA17G...@bath.ac.uk...
> Robert Keeter <rke...@earthlink.net> wrote:
> Your question consequently reduces to: are there any bipedal animals
> who once went about on all fours?
>
> The answer is "yes": penguins, kangaroos, T-tex, man - all the bipedal
> animals in fact.
I don't know about this, at least I have questions about penguins.
All vertebrates originated as fishlike critters in the seas, with fins and
no limbs to speak of. From these you have the terrestrial pioneers, reptiles
and amphibians, and we suspect they evolved fore and hind limbs from
pectoral and anal fin structures. That adaptive radiation seems to have led
to quadrupedal "terrapins," which is a term I just invented. Feel free to
use it; I think it's catchy...
Then you have the birds...a strange bunch of critters, with the pectoral
fins (perhaps even more caudal structures, like gills?) evolved for
flight...(think of flying fish).
All birds are "bipedal," but they arrived at that condition by following a
different path from their reptilian (mainly dinosaur) and mammalian cousins.
Neurocop
"Neurocop" <thal...@ix.netcom.com> wrote in message
news:98k43j$8up$1...@slb7.atl.mindspring.net...
I forgot to mention the arthropod lineage. Sea dwelling arthropods, such as
the eurypterids, had "legs" they used to crawl along the sea-floor, much
like crabs. But they are too far back in the evolutionary time-line to be
terrestrial vertebrate ancestors. One could make a fantastical argument that
birds evolved separately from flying arthropods and became vertebrates by a
sort of convergent evolution, but that would be really absurd.
Bob Keeter
<thal...@ix.netcom.com> wrote:
Only if ones "claim to fame", hope for publication, or doctorial
thesis, did not hinge on advocating such an "unconventional" theory!
;-)
What! No takers! 8-))))
Regards
bk
pete
`"Tim Tyler" <t...@cryogen.com> wrote in message news:GA17G...@bath.ac.uk...
`> Robert Keeter <rke...@earthlink.net> wrote:
I hope you're jesting here. Just to be pedantic, all air breathing
vertebrates got here via the amphibians, who were (and mostly are,
except for the secondarily limbless ones) quadrupedal. Birds, and
all dinosaurs (but not all reptiles), came from a creature which was
secondarily bipedal, sort of a reptilian squirrel-like animal, which
likely developed its bipedality by first climbing, squirrel-like,
then returning to the ground as a bipedal runner. The bipedal past
of dinosaurs is evident in their unequal for and hind limb lengths,
even the thoroughly quadrupedal large herbivores. I'm surprised
that someone who's taken an anatomy course would even suggest in
jest that gills could turn into wings. Good grief.
--
==========================================================================
vin...@triumf.ca Pete Vincent
Disclaimer: all I know I learned from reading Usenet.