Re: AAT Theory

Paul Crowley (
Sat, 16 Sep 95 23:14:04 GMT

In article <42tql9$> "chris brochu" writes:

> Hypothesis 1: Some of these arboreal primates began to walk bipedally on
> land, perhaps to move efficiently from one forest to another. Tree to
> land directly.

This is not an hypothesis at all. It explains nothing. It's got no beef.
It's on the level of "base metal -> alchemy -> gold".

An hypothesis explaining progress to bipedalism must state the selective
pressures that would operate every day for a million years. It's not
enough to talk of occasional behaviours, such as display routines. It
must cover normal activites: escaping predators, finding food, beating
off rivals, etc. In the absence of special factors all these will just
select the best movers - the best quadrupedal movers.

It seems to me that a complete change of lifestyle is needed. Regular
wading in deep water would do it; the apes would have to keep their heads
up. But how could regular wading form part of a million year lifestyle?

The AAT hypothesis may or may not be true - but it seems to be the only
one around. Until there's another one, all the sniping on side issues is
pointless (e.g. whether homo sapiens and/or other terrestrials can/could
detect smells in salt/fresh water - who cares? so what?).