Re: First Family and AAT

Thomas Clarke (
11 Oct 1995 13:40:50 GMT

In article <45f60m$> Alex Duncan
<> writes:
> In article <45cl7o$> Tom Clarke,
> writes:

> >> if
> >>becoming a biped is such a wonderful adaptation to an aquatic existence,
> >>why aren't polar bears, walruses, alligators, mososaurs and otters all
> >>bipedal?

> >I will try a rhetorical device to show the vacuousness of this argument.

> >In other words why aren't chimpanzees and gorillas bipedal?

> Well, it seems you got the point of my argument. AATer's are always
> asking "if bipedalism is so wonderful, how come chimps aren't bipedal?"
> This certainly reveals some lack of knowledge about the way evolution
> works. But it is also just plain bad argument, as I was trying to point
> out by turning it around.

Now I am really confused. Wait I think I get it.
You want to say that a consequence of my position is that starting with
ANY genetic stock, similar conditions will result in similar adaptations.
E.G. dolphin-like apes as a result of adaptation to water.

This is silly. Different stock results in different adaptions, although
there are broad similarities, A seal is not a dolphin is not a dugong,
although there are broad similarities. The evolution of each began with
a different quadruped. The result of an arboreal ape adapting to water
would be still different. Of course the adaptation was cut short anyway,
it is now at least 4MY past the putative aquatic episode.

I then turned it around to make the easier to support argument that
starting with the SAME genetic stock (arboreal apes), you should arrive at
similar adaptations given the same environment. Hence if the African
land environment gave rise to bipedal hominids, why not bipedal chimps.
Why chimps as a seperate species at all?

By the way how does eveolution work in your view?
My view is that change occurs in the direction of increasing fitness.
If there is not difference in fitness with respect to some trait, then
it can vary or drift randomly. Are you saying that bipedalism has
no fitness value?

Tom Clarke