Re: Convergent traits... was Re: AAT Theory

J. Moore (
Tue, 17 Oct 95 23:18:00 -0500

Cl> TC> No law of course, only the observation of the convergent evolution
Cl> TC> of similar traits to fill similar niches in vastly different species
Cl> TC> and locales.

Cl> > Like those convergent traits seen among all aquatic marine
Cl> > mammals: smaller or non-existent ears; shorter or non-existent
Cl> > limbs; extremely large, heavily lobulated kidneys; and young that
Cl> > are born quite advanced compared to similar terrestrial mammals
Cl> > (for example, seals as opposed to land-based carnivores), or
Cl> > which grow very quickly, or both. We have none of these traits,
Cl> > and as far as our young are concerned, we've changed in the
Cl> > opposite direction from all aquatic marine mammals. Why are
Cl> > humans so conspiciously the odd man out in all these ubiquitous
Cl> > convergent traits?

Cl> Thus humans are the odd man out because they took a step into the water
Cl> and then retreated three steps back.

This demonstrates the erroneousness of the AAT's claim to be
"simpler" or "more parsimonious" than land-based theories.
In your above scenario, the AAT thus requires that there be massive
changes to an aquatic environment followed by a reversal of these
changes. Yet the AAT's "evidence" rests on the idea that these
aquatic changes remained. It further requires that the only
skeletal changes which remain are, suspiciously, precisely those
which we would expect from a land-based transition.

Not only does the AAT require this special pleading, the supposedly
"simpler" and "more parsimonious" AAT also requires two massive
changes while land-based theories require only one change.

Cl> Ian Tattersall in the "The Fossil Trail" points out the origin of
Cl> bipedalism as the key problem. Was it environmentally driven,
Cl> behaviorally driven or what? I really think the environmental ideas
Cl> behind the AAT have something to offer.
Cl> Tom Clarke

As long as the AAT proponents refuse to address key problems in
their theory, and as long as they produce "evidence" which is at
odds with the facts and/or with evolutionary theory, it can have
nothing to offer. If AATers want to have "something to offer",
they need to learn to live with and address valid critiques.

Jim Moore (

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