Re: aat-reply to Moore.

Gerrit Hanenburg (
Wed, 12 Jul 1995 22:56:51 GMT (Pat Dooley) wrote:

>When your guys explain why full time bipedalism is unique to humans,
>why no other primate occupying a similar range of habitats failed to evolve
>a similarly "advantageous" mode of locomotion,and how it evolved without
>conferring fatal disadvantages on the intermediate forms between the
>original mode and 100% bipedalism, I might take your argument from
>authority seriously.

The fact that some species "hits" upon something "advantageous" doesn't
mean other species more or less like it will hit upon it too.Evolution
doesn't work that way (or else all primates would have had big brains).
You seem to forget about the chance component in evolution and the dependence
on initial conditions.Natural selection is an opportunistic process.ONCE you
hit upon something "good" it can be selected,not prior to that.Other species
may never "learn the trick" no matter how close they are to it.

As far as the "fidelity" of intermediate forms is concerned:".....part of an
eye is better than no eye at all." R.Dawkins.The Blind Watchmaker.
A certain form of intermediate bipedalism may have been advantageous
to a certain primate just like a lightsensitive spot may have been
advantageous to some cambrian lifeform,the decendants of which may have
evolved it into a "fullblown eye",via progressively "better" intermediate
The mode of bipedalism in A.afarensis may not have been as "good" as in
modern humans (assumed to be 100 % bipedal) but "When it existed,afarensis
was a successful,stable species,on the way to nowhere".R.Leakey.
If we fail to imagine how it could have been successful without less than
"100 % bipedality", then that is a lack of imagination.
Bipedalism evolved in ecological circumstances different from todays.The
question is how much different.

>But your guys don't tackle the evolutionary issues very well. Their theories
>remain as speculative as the AAT, fail to account for other human
>anomalies,and ignore too many evolutionary ideas.

You have been taking part in some discussions on AAT issues (e.g. sweating
in primates) in which the "opponents" of the AAT have put forward some sound
arguments.Your generalization seems to me a little off the track.