Re: Aquatic Apes 3 of 5
Pat Dooley (patdooley@aol.com)
6 Dec 1994 01:00:08 -0500
In article <1994Nov8.155818.7297@arl.mil>, Troy Kelley
<tkelley@hel4.brl.mil> writes:
> Troy quoting Philip Nicholls :
>
>>Chimpanzees, gorilla's, bonobo's, orangutans and gibbons have all been
>>observed walking bipedally -- sometimes for considerable differences.
>>Chimpanzees in particular will walk bipedally if they want to carry
>>something. When foraging on low bushes, they will stand erect.
By citing a tendency for our closest relatives to walk bipedally, Philip
is
simply demonstrating that a hominid going into water is likely to adopt
a bipedal posture.
He misses the point that bipdalism is much less efficient for the other
apes
than their usual mode of locomotion. Conversely, most of us humans avoid
knuckle walking.
How do we know the common ancestror of around 12 mya was not a knuckle
walker. About all we do know for certain is that it wasn't truly bipedal.
>I am not sure of the point you were trying to make here. But I will say
>that baboons spend most of their time on the open savannha, especially
>when compared to other apes. They are not bipedal. And if there are so
>many advantages to being bipedal, especially in a grassland or savannha,
>then why don't baboons "go bipedal".
AAH opponents generally ignore comparative evidence and the principle
of convergent evolution. Human ancestors were a special case even before
they evolved brains big enough to make them a special case.
>>o Reduction in the surface area exposed to UV radiation from the sun
>>when moving on savannas.
>>
>>o Greater evaporative cooling by exposing more skin to moving air.
>>
>>The last two have been tested by Pete Wheeler using protohominid
>>models with thermal sensors.
I call this the heliotropic ape theory. The ape keeps his head and body
pointed
at the sun to reduce UV radiation. Reducing the surface area doesn't do
anything
to protect the face, shoulders and upper back from UV radiation. Severe
sunburn
and increased skin cancer rates are not a price that other savannah
animals
were willing to pay for the advantages of hairlessness.
>
Pat Dooley rejoining the fray
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