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Re: AAT:A method to falsify
Troy Kelley (tkelley@hel4.brl.mil)
Thu, 5 Oct 1995 13:12:40 GMT
Subject: AAT:A method to falsify
From: Phillip Bigelow, n8010095@cc.wwu.edu
Date: 4 Oct 1995 15:38:42 -0700
In article <44v2di$itb@henson.cc.wwu.edu> Phillip Bigelow,
n8010095@cc.wwu.edu writes:
>Although most of the threads regarding AAT center around
>anecdotal evidence, or arguing whether a trait is
>"aquatic", I have noticed that few of my compatriots have attempted to
>falsify the theory at it's root.
> The question to ask is: "Is it even physiologically possible for a
small,
>hairless hominid to be a ubiquitous-wader/occassional-swimmer, and not
have
>problems with hypothermia?"
> A year or so ago, I posted a summary of body masses for all
>hairless-water-bound mammals (ie., the hippo and the entire group
Cetacea),
>and found that the hairless-aquatic group was STRONGLY weighted
numerically
>toward animals that were 250 pounds. The Bell-shaped curve also tapered
off
>slowly toward higher-mass animals, but it tapered off SHARPLY toward
>low-mass animals.
> I recall that the smallest cetaceans were slightly less-massive than a
>chimpanzee, but these cetaceans have very low surface-area/volume ratios.
>Chimpanzees, humans and the purported "aquatic ape", if it were
Lucy-size or
>smaller, would have much greater surface-area/volume ratios.
> A good test for some future researcher would be
> to predict how small a hairless hominid can get, and
not
> be limited by thermodynamics.
>If even a FAT hairless primate of Lucy's mass could not be habitually a
>wader/swimmer without suffering from hypothermic effects (even in warm
>water), then the whole theory is essentially demolished.
>I predict the key to dismantling the theory will be surface-are/volume
>ratios, heat-retention, and metabolism.
> <pb>
What???? We went around this block before. Seems to me we came up with
quite a few mammals that were less than 250 pounds that get along just
fine in aquatic environments. The pigmy and fresh water dolphins come to
mind. Also, the normal distribution is skewed toward heavier mammals
because obviously fat deposits do help in the water, and you have a
mammal like the blue whale at one end of the distribution.
Also, the fat content of these animals (fresh water dolphins) was right
around 20 percent. The fat content of moderday humans is right around 12
percent. So early homo might have been a little more or a little less fat
than the current 12 percent. But 20 percent applies to an animal which is
in the water ALL THE TIME. I don't know why I have to keep repeating this
but AAT says that early hominids were SEMI-AQUATIC, not completely
submerged in water all the time. So 12 percent seems like a perfectly
acceptable fat content for a semi-aquatic mammal in a warm environment.
The hypothermic argument is silly when you consider a) there are other
animals that are around the weight of early homo spend all day in the
water b) if you can assume that the fat content of early man is similar
to the fat content of early homo, there is plenty of fat to keep early
homo warm in warmer water temperatures that were consistent with Africa
4-12 MYA c) Africa was indeed warmer during some of the period that AAT
is supposed to have occurred d) AAT contends that much of the water
activity occurred during the day, which is when water temperatures are
the warmest and physical activity is the highest. I mean after all, AAT
doesn't contend that early homo was sleeping in the water.
Anyone who has spent a day at the beach, or a lake, or swimming all day
in a river, knows that the hypothermia argument is a weak one.
Troy Kelley
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