From: Crosby_M (CrosbyM@po1.cpi.bls.gov)
Date: Fri Jan 17 1997 - 14:18:44 MST
On 17 Jan 1997 Guru George <gurugeorge@sugarland.idiscover.co.uk>
Wrote:
<The 'savannah' scenario just doesn't cut it, so far as I can see>
John K Clark responded:
<I agree, that never made much sense to me, if anything it seems that
bipedalism would do better in a dense jungle that a open savanna, but
if the savanna theory is wrong that doesn't mean that the Aquatic Ape
theory is right.>
Given that we evolved from apes, which were already semi-erect and
adapted primarily to brachiating through trees, if we stayed in the
dense jungle I doubt if we would have evolved to full bipedalism -
wouldn't we have just continued swinging and climbing through the
trees or crawling around under the bushes?
On the open savanna, on the other hand, there's several advantages to
bipedalism:
* given that 'we' were _already_ semi-erect, it's unlikely we would
have reverted back to something 4-legged;
* so, the need to cover greater distances meant we would have needed
an alternate way to run fast, e.g., bipedalism;
* being able to stand fully erect also allows the animal to see
farther across the open savanna and more ably find prey or avoid
danger;
* finally, there's the 'throwing hypothesis' which proposes that,
starting with the pre-existing combination of arms and legs (plus
already being an omnivore), the best adaptation for earning a living
would be to hunt game by throwing projectiles.
Mark Crosby
P.S. I recall the List discussing this 'throwing hypothesis' early
last fall or summer but can't remember what evidence some cited
against this or the savanna scenario.
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