Re: Bipedalism and theorizing... was Re: Morgan and creationists
John Waters (jdwaters@dircon.co.uk)
26 Sep 1996 09:33:11 GMT
Gerrit Hanenburg <ghanenbu@inter.nl.net> wrote in article
<DyAELq.B32@inter.NL.net>...
> In Goodall's "The Chimpanzees of Gombe" there are two
instances of
> chimp mothers assuming a bipedal posture while carrying an
infant
> (pp.438 and 556).One with the infant in ventro-ventral
position and
> the other in dorsal position.They seem to hold on pretty well
despite
> the activity that is involved.
JW: For readers who do not have ready access to this book, I
think we should make it clear that the photographs do not imply
any long distance carriage of the infants comparable with (say)
knucklewalking. In one case, the mother is attacking another
female; while in the other case the mother is attacking a
(stuffed) leopard.
>
>
> This argument seems to imply that early bipedal physiology had
be as
> efficient as it is today in order to be adaptive.
> I don't think this has to be the case.The important point is
whether
> or not a particular behaviour is *effective* in relation to
the goal
> the organism is supposed to achieve.
JW: I was not claiming that early bipedalism had to be
particularly efficient; merely that it had to be capable of
doing the job in hand. Therefore I entirely agree with your
point about being *effective*.
That said, going back to the previously quoted example of the
chimp (faben) with the paralysed arm, it should be noted that
such an arm is just so much dead weight. The arm would probably
weigh about 5 pounds. This is about the weight of a new born
chimpanzee infant. Which implies that if an nursing female
carried her baby in her arms, twisting slightly to one side, the
centre of gravity would be sufficiently favourable to allow the
same long distance walking as was achieved by faben. Thought of
the day?
John
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