Re: AAT Theory
Elaine Morgan (Elaine@desco.demon.co.uk)
Fri, 06 Oct 1995 13:26:17 GMT
In article: <44ebnt$djc@kira.cc.uakron.edu> r3dlb1@dax.cc.uakron.edu
(David L Burkhead ) writes:
>
All the hominids of which I have knowledge were also tool
> users.
Is there any evidence that Lucy was a tool user?
We are superb at doing extended exertion under high
> thermal stress. There is a trade for this last one, of course, in
> that we expend a lot of water for that. However, with the
> availability of waterholes (which _are_ found on the savannah) we can
> function effectively at times of the day when most other animals have
> to rest
Geladas function effectively throughout the day without expending a lot
of water - a much cleverer trick. The idea that functioning throughout
the midday period would have been an advantage for the first hominids has
very little going for it and its chief proponent Peter Wheeler has now
tacitly abandoned it in favour of depicting hominids that took prlonged
siestas. The midday shift would not have been an unoccupied niche, since
geladas were the commonest primates in Africa at the time of the
ape'human split.
> > Go look up turbulent vs laminar flow separation
> >>drag in bluff bodies. (This kind of thing is one of the reasons the
> >>"obvious" is so often wrong.)
> >
Bipedalism in water as a means of locomotion is, as you
indicate,extremely inefficient. It would never have been adapted in water
on account of its effectiveness in getting from A to B. Most
primatologists now agree that it would not have been adapted on land,
either, on account of its effectiveness in getting from A to B. That is
why they keep trying to think up non-locomotor advantages it might have
conveyed.
The non-locomotor advantage for a wading primate - especially for a
female carrying an infant (if she tried to swim while it was clinging to
her belly she would drown it) is that it keeps her head above water. The
claim is not that it would be easier or faster. The claim is that she
would have had *no option*. The proboscis in a precisely similar
situation resorts to it for exactly the same reason.
>
Elaine
> >
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Elaine Morgan
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