Re: Okay seriously now (AAT again)
Pat Dooley (patdooley@aol.com)
13 Dec 1994 22:55:19 -0500
In article <39f6og$ffj@rebecca.albany.edu>, pn8886@csc.albany.edu
(NICHOLLS PHILIP A) writes:
<< deletions>>
>One fossil ape, Oreopithecus, shows considerable "straightening" of the
>pelvis in that the blade of the pelvis is broader and shorter. This
>is consistant with primates who engage in vertical suspensory feeding.
Apes and other primates, because of their arboreal existence
are already partially adapted for bipedalism. If a distant ape
relative was forced into water, it would wade bipedally, whereas
a quadruped would swim. We might note that the ancestors of
all fully aquatic mammals were quadrupedal and observe that Proboscis
monkeys, which have adopted a partially aquatic life in their
recent evolutionary history, wade in shallow water and swim
in deeper water. The Oreopithecus, an extinct ape that apparently
lived in marshland, had undergone skeletal changes to its pelvis
that suggest it was bipedal or a swimmer or both. It was known
as the swamp ape and mistaken for a human ancestor very early
in this century on the basis of its pelvis.
>All of the features that you are citing with regard to the aquatic
>ape garbage are MODERN features. When it comes right down to it,
>anL aquatic lifestyle places certain demands on the skeleton that
>are not reversable. These include a reduction in the size and
>robusticity of the pelvic bones. ALL AQUATIC AND SEMI-AQUATIC
>mammals show this reduction. Modern humans do not, neither do
>any of the fossil hominids which have yielded pelvic remains.
The evolution of bipedalism required major skeletal adjustments.
According to Richard Leakey and Roger Lewin (who studiously ignore
the AAT), "the evolutionary shift from quadrupedalism to bipedalism
would have required an extensive remodelling of the ape's bone
and muscle architecture and of the overall proportion in the lower
half of the body. Mechanisms of gait are different, mechanics of
balance are different, functions of major muscles are different.
An entire functional complex had to be transformed for efficient
bipedalism to be possible." cf. "Origins Reconsidered".
These experts give a rather different perspective to Phillip
Nichols bluster about all apes being nearly bipedal. While it turns out
that bipedalism can be as efficient as quadrupedalism
in some circumstances, the problem is that it can't always
have been an efficient mechanism during its evolution. Mrs
Qradruped ape doesn't suddenly give birth to 100% Bipedal
offstring. So, during the transition from some quadrupedal
gait to a bipedalism, which would have taken millions of
years, the ape would have been especially vulnerable
to predators. Evolution doesn't give any species a holiday
while it evolves some feature that would be advantageous
when it was fully developed. I called this the principle of
Non-disadvantageous intermediates: Evolution will never proceed
from one form to a more advantageous form if the intermediate
form is disadvantageous. The AAT provides a plausible
scenario for the evolution of bipedalism backed up by
the obsevation of what some other primate species do in
water - they wade.
Bipedalism had fully evolved by the time of Lucy 3.5 mya.
That's modern? More like another bit of conjecture from
Phillip Nichols. The fat layer is modern? Proof please;
not another implausible scenario. Hairlessness is
modern? Any evidence willingly inspected. Sweating
modern? maybe - it doesn't work very efficiently.
According to William Montagna,
author of "Advanced Views in Primate Biology", "sweating is an enigma
that amounts to a major biological blunder: it depletes the body
not only of water but also of sodium and other essential eloctrolytes
that are carried off with the water".
Sorry "Chris" - your calling a theory garbage doesn't make
it garbage.
Pat Dooley
--
Philip "Chris" Nicholls Department of Anthropology
Institute for Hydrohominoid Studies SUNY Albany
University of Ediacara pn8886@cnsunix.albany.edu
"Semper Alouatta"
>>Why the hell
>>would humans have grown EXTRA LONG hindlegs? Answer: the evolutionary
>>pressures were different. Long legs are a liability in the water.
>
>Another evasion? It is well known that the length of the hominids legs
>have changed at least several times since the earliest known bipeds.
>Some have been found which were quite short indeed.
>In general it is quite unfair to point at a modern feature which is
>inconsistent with aquatic life and call that a counter-example to the
>hypothesis. A lot can change in five million years. Your comment about
>brain size is another example of this kind of disingenuous argument,
>already addressed by someone else, so I'll leave that one alone.
All of the features that you are citing with regard to the aquatic
ape garbage are MODERN features. When it comes right down to it,
anL aquatic lifestyle places certain demands on the skeleton that
are not reversable. These include a reduction in the size and
robusticity of the pelvic bones. ALL AQUATIC AND SEMI-AQUATIC
mammals show this reduction. Modern humans do not, neither do
any of the fossil hominids which have yielded pelvic remains.
--
Philip "Chris" Nicholls Department of Anthropology
Institute for Hydrohominoid Studies SUNY Albany
University of Ediacara pn8886@cnsunix.albany.edu
"Semper Alouatta"
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