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Re: AAH: humans long-distance runners?
Pat Dooley (patdooley@delphi.com)
Mon, 12 DEC 94 22:07:25 -0500
Phil Nicholls <pn8886@csc.albany.edu> writes:
>Pat, please try to remember that we are talking about EVOLUTION here
>and not intelligent design. Evolution produces the best solutions to
>problems of survival GIVEN THE CONSTRAINTS OF EXISTING MORPHOLOGY.
Enter your response to the quote. Control-Z when Complete. /HELP for Help.
Evolution produces outcomes that look like intelligent design. That's
why computer scientists have found genetic alogorithms very effective
in solving some classes of optimisation problems. Let's return to the
issue of existing morphology. African apes have 52% eccrine glands
to 48% acropine glands. If the common ancestor of hymans and apes
moved to an environment that placed them under thermal stress
then one woul expect them to evolve a sweating mechanism based
on the abundance of acropine glands. That is the mammalian approach
that has evolved countless times over millions of years. It turns
out however, that humans have 99% eccrine glands to 1% acropine
glands, and human sweating is based on eccrine glands; a unique
evoltionary solution. While hominids may have a tendenct towards
increasing the ration of eccrine to acropine glands, in humans
the tendency went ballistic. If acropine glands were abundant
when environmental pressures required the evolution of
a heat removal mechanism, then, given the constraints of
existing morphology, the answer would have been acropine
sweating. It didn't happen that way so one is forced to
conclude that the acropine glands had almost disappeared
before human sweating evolved. The AAH provides a plausible
explanation.
>As I have pointed out several times, sweat cannot be a form of
>salt excretion because sweat is hypotonic relative to body fluid.
>If sweat were a salt excreting mechanism then sweat would be
>hypertonic. That's basic chemistry. You also don't take into
>consideration the fact that increased eccrine glands are a
>hominoid trend
And, as the AAH proponents have pointed out many times,
the salt excretion is a hold-over form an aquatic phase
that ended at least 3-4 million years ago and before
eccrine sweating evolved and changed the ration of water
to salt. It is in the same vestigal state as the
human stress response of sweaty palms; we don't need
to moisten our palms to improve arboreal grip but
we still do it. When a trend goes off the scale
it needs explanation. 52
Pat Dooley
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