Re: bipedalism and AAH

Pat Dooley (
8 May 1995 21:04:34 -0400

Harry Erwin writes :

>Bipedalism is an arid-country strategy that involves maximization of the
>search rate. Joel Brown did work on this at the University of Arizona
>back in the 1980s.

Objection 1: The evolution of bipedalism predated the shift to the

Objection 2: Even if bipedalism did maximise search rates, one still has
address the issue of disadvantageous intermediates. Let's clarify that by
parallel example. Being able to soar like a vulture would definitely
the search rate, but no primates have evolved such an ability. The problem
is that the intermediate forms; the semi-winged non-flying primates, would

be far more vulnerable than their ancestors to predation.

While the adaptations for bipedalism are not as radical as those required
flight, they are still quite dramatic, especially given the time frames
Elaine Morgan does a great job in Scars of Evolution in explaining the
required for bipedalism.

Objection 3: If you want to maximise the search rate in arid country, you
have to minimise water loss; humans are very inefficient water conservers,
mainly due to their hairlessness and poorly regulated sweating mechanism.

Pat D