Re: AAH
Phil Nicholls (pn8886@csc.albany.edu)
8 Dec 1994 01:58:47 GMT
In article <3c0qrj$c7g@newsbf01.news.aol.com>,
Pat Dooley <patdooley@aol.com> wrote:
>In article <CzAD0q.21t@microsoft.com>, russpj@microsoft.com (Russ
>>Paul-Jones) writes:
>>
>>1. It is hard to know what kinds of characteristics to look for,
>> since I don't know what the AA looked like, and I don't know
>> what mechanisms preserved the aquatic adaptations during
>> millions of years of evolution in a non-aquatic environment.
>> This objection is pretty much keeping the hypothesis, well,
>> hypothetical in my mind. I want a model for the AA critter
>> and some predictions for the chain of critters between us.
>>
>The starting point has to be creature that was the common ancestor of
>gorillas,
>chimpanzees and humans. Given that starting point, and I suspect it wasn't
>that much different from a modern ape (homo sapiens excepted!), one needs
>to look at what adaptations could be made if such a creature was to become
>partially adapted to aquatic life. The probiscus monkey provides some
>clues
>as do Japanese Macaques.
And exactly what do you base this on? Also, what information do the
"probiscus" monkey and Japanese Macaques provide?
>The other starting point is to look at the characteristics of other
>mammals that
>have made to the transition to aquatic life.
Just don't look at the skeletal modifications they have made, right?
>
>If we ignore the AAT at this point, and pose the hypothetical question of
>what evolutionary
>changes would we expect if we forced a forest ape to adapt to an aquatic
>life, we might
>get a few hints. How could we force the ape to adapt? Place it on an
>island and slowly dry
>out the forest cover.
>Would it be hairless?
>
>Above a certain mass, aquatic and wallowing mammals are hairless.
So you are proposing convergent evolution? Exactly what do a whale
and a pig have in common that would lead to hairlessness?
>Would it have subcutaneous fat?
>
>Since this contributes to thermal insulation, bouyancy and streamlining,
>and is
>universal amongst aquatic mammals, you would have to suppose our ape
>would be fat.
Subcutaneous fat is found in all mammals.
>Would it be bipedal?
>
>If its ancestor was a arboreal and/or a knuckle-walker, then bipedal makes
>sense.
>Probiscus monkeys have been filmed walking bipedally
So have chimpanzees, gorillas, baboons, squirrel monkeys, sifakas and
nearly every other primate.
. Macaques wade into
>water. Wading on two legs makes more sense for an ape than reverting to
>four
>legs, like a herbivore.
Except that Macaques only stand when the are in water too deep for them
to wade into as quadrupeds. I have seen numerous films of them wading
into shallow water to wash sweet potatoes or sort sand from grains and
they are usually quadrupeds.
>One could go on, but you get the general idea.
>
>>2. This is why I think that my first objection will be so hard to
>> satisfy. It will be hard to design a mechanism for maintaining
>> those aquatic adaptions modern humans have that doesn't also
>> work as a reason to evolve them in a non-aquatic environment.
>> If subcutaneous fat is advantageous in a savannah environment,
>> then we don't need the AAH to explain it's existence in modern
>> humans. If it is not, then the AAH has quite a bit of
>> explaining to do to show why it survived until modern times.
>>
>If subcutaneous fat was an advantage in a savannah environment, then it
>would
>be as universal amongst savannah animals as fur. Nobody that I have read
>has been
>able to make such a case.
Because if you will pardon my attitude it is a dumb question. Because
we evolved and were not designed from scratch.
--
Philip "Chris" Nicholls Department of Anthropology
Institute for Hydrohominoid Studies SUNY Albany
University of Ediacara pn8886@cnsunix.albany.edu
"Semper Alouatta"
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