Re: [asa] Improbability of Homo Sapiens?

From: David Campbell <>
Date: Fri Feb 09 2007 - 13:26:53 EST

> For example, the large brains of humans have marked adaptive disadvantages, requiring as they do an expensive metabolism, a long gestation period, and a childhood lasting more than 25% of the average total life span.<

But the large brains also convey a variety of advantages. The exact
set of selective pressures over the history of the lineage, along with
genetic drift and other factors, will determine exactly what features

> * Being the only extant bipedal land vertebrate. Combined with an
> unusual eye-hand coordination, this permits dextrous manipulations of the
> physical environment with the hands;

Birds are also bipeds, though most have forelimbs specialized for
flight. Uniqueness does not equate to improbability; there are
numerous extinct bipedal reptiles. The hand-eye coordination seems to
relate ancestrally to primate tree-climbing; apes are fairly good at
manipulating the environment with their hands.

Dr. David Campbell
425 Scientific Collections
University of Alabama
"I think of my happy condition, surrounded by acres of clams"
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Received on Fri Feb 9 13:27:24 2007

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