Re: Specification for theories on human evolution

Paul Crowley (
Wed, 15 Nov 95 19:10:09 GMT

In article <48ablb$> "Alex Duncan" writes:

> >e11 The reasons for the development of bipedalism must be clearly shown.
> Can you explain exactly what it is you mean by "reasons"? Lots
> of potential adaptive advantages for bipedalism have been offered, but
> apparently they don't qualify as "reasons".

It is my thesis that the adoption of bipedalism would have had
enormous disadvantages (helpless infants, impeded mothers, no
safe refuge in the trees at night, etc.) if adopted for any of
the standard reasons. Here I block copy from a posting by Jim
Moore quoting Phil Nichols in science.biology.evolution on 16 Oct:

Pn> - when hands are need to carry food.
Pn> - to obtain a better view of the surrounding area.
Pn> - jumping across small brooks
Pn> - treat displays.
Pn> - when watching an unusual part of the surroundings
Pn> - when locating another member of the group
Pn> - greeting and courtship displays.

I'm sure he meant "threat displays" not "treat displays" as you have
pointed out elsewhere.

Consequently bipedalism must have been adopted for most particular
reasons. These reasons can be identified to (IMO) a fair degree of
probability with a little bit of thought.

Here are some clues:
The protohiminids can be thought of as being like modern chimps in
morphology and behaviour. They were diurnal, omnivorous, and had
good social structure - so they could cope with diurnal predators.
They actively explored a variety of habitats. Here's the
important bit: they had recently acquired the same sort of tool-
using capacity as now possessed by chimps.

So what's the large food resource previously unexploitable by
hominoids which they got at by using stones as tools (and I don't
mean nuts).

Anyone want to guess?