Re: AAT Theory
Thomas Clarke (clarke@acme.ist.ucf.edu)
6 Oct 1995 16:57:13 GMT
In article <450oe2$39s@geraldo.cc.utexas.edu> chris brochu
<gator@mail.utexas.edu> writes:
> In article <450jm9$43e@news.cc.ucf.edu> Thomas Clarke,
> clarke@acme.ist.ucf.edu writes:
> >More literary/scientist style clashing.
> >I really do not understand the aquaphobia of the professionals.
> >If Morgan's literary style so anathema to them, that they must eschew
> >any possibility that water played a role in hominid evolution in
> >order to avoid all possible reference to Morgan's literary works?
> I vigorously disagree. The difference is not literary, but procedural.
> Ultimately, it comes down to this - scientists look for patterns, and
> then derive processes that might explain them. AAS proponents are doing
> the reverse - they have selected a preferred process, and then try to
> shoehorn the pattern to fit it. It has nothing to do with literary style.
Perhaps we will forever disagree, but I see the AAT as squarely within
the process of science. The data are:
Human Ape Common Ancestor
*Bipedal Knuckle Walking Arboreal
& a LARGE array of skeletal differences jaws, skull etc.
I defer to those more expert in this area
*Naked Hairy ??????
*Skin Fat No Skin Fat ??????
Large Brain Small Brain Small Brain
*Different cooling strategy - sweat glands ??????
No Estrous Estrous ??????
Menopause No menopause ??????
*Descended Larynx Undesc Larynx ??????
Speech a corollary/cause of this?
Immature Birth Mature Birth ??????
Other differences I cannot think of right now.
Plus a sketchy series of skeletal fossils along the lines leading
from common ancestor to ape and to human.
The problem is to account for the eveolution of common ancestor into
ape and into human.
Thomas Hardy, disecting some marine mammals was struck by the similarity
of their fat layer to the human fat layer. He had an "Aha!" experience
and saw that an aquatic phase in human evolution could account for all
the starred data. He recognized a pattern; the pattern of adaptions
often found in aquatic and semiaquatic animals. Seems like pretty
standard science to me. One hypothesized environment along the
eveolutionary path accounts for nearly half of the human ape differences.
The differences exist independantly of the AAT. They were not invented
by AAT proponents to make people like seals. Hardy cut into seal flesh
and was reminded of his medical school days disecting human flesh.
> As I wrote earlier, the pattern we see suggests a lineage of terrestrial
> quadrupedal primates evolving into a lineage of terrestrial bipedal
> primates. There is no implication of an aquatic phase, regardless of the
> degree. So far, all "evidence" I've seen to support the AAS falls short.
That is a perfectly valid opinion.
> AAS supporters, conversely, have given us a moving target:
> "Hominid fossils are found in aqueous deposits!"
> So what - most fossils are, and this need not imply living in water.
I, for one, do not dismiss the locale of the fossils that lightly.
> "OK, so the fossil record is irrelevant. But look - we show a diving
> reflex, just like whales!"
> Yes - and rabbits, goats, and many other mammals.
I am beginning to think the diving reflex argument may be an example
or overenthusiasm by the AAT proponents.
> "Fine, then. But we're hairless, just like swimming mammals, right?"
> Well, sort of, but within our size range, swimming mammals tend to be
> furry, and not all hairless mammals are aquatic.
I think most tropical swimming mammals of size are hairless.
Name a hairless (non-subteranean) mammal that did not have an
aquatic episode in its past.
> "OK, so maybe not good evidence. But on land, we would have been easy
> prey for cats!"
> Perhaps, but in the water, we would have been even easier prey for
> crocodiles.
> "If so, then we must have lived on beaches!"
That was always my picture. The proto-hominids in their
ocean-side "tropical paradise".
In another post I suggested that the predator (non?)problem
may have placed a premium on bipedalsim because it gave the
proto-hominds an ability to quickly shift from land to water
and vice versa, avoiding whichever threat was greatest at the moment.
> Crocodiles occur on beaches.
> "Stuck-up academic!"
Who said that? Not moi, surely! I can be pretty pretentious
when I'm writing mathematics.
> Another characteristic is how much closer to land we get as the AAS
> progresses. As far as I can tell, it's gone from "swimming ape" to
> "wading ape" to "ape that sometimes wades out into the water and jumps
> out at the earliest sign of danger."
It's still swimming ape. Or rather ape that lives on the shore
and goes into the water often to gather food and must stick its
head in the water to gather that food.
> The problem is not writing style, except for cases in which some people -
> on both sides of the issue - have not been clear on what they were
> saying. I'm as guilty as the rest in this regard.
> Scientists don't try to prove things - they try to disprove them.
Now this I diagree with, at least with the literal words.
Newton took Galileo's gravity observations and extended them with the
inverse square law to the moon so that using the calculus he was
able to derive Kepler's elliptical orbit of the moon.
Well if he had done the calculation and it had come out wrong the
inverse square law of gravity would have disproven. But the
calculation worked. To me this is "proof" of the theory.
Of course over the years increasingly precise measurements uncovered
problems like the precession of Mercury that led to Einstein's
theory which so far has been proven correct.
>From this standpoint, my training in the hard sciences the AAT looks good.
Start with the single observation of a fat layer - hypothesize an
aquatic episode. You would then expect other aquatic characteristics.
Lo and behold there are some, but also some are missing. But this is
"soft science", the aquatic episode was a long time ago with a lot
of evolution since, so some yes, some no is, to me, pretty good evidence
for the AAT. You concentrate on the failed aquatic characteristics and
reject the theory. Well fossils will tell eventually.
If I apply the same viewpoint to the "land theory", one would expect
a hominid to display characteristics of other savannah dwelling
animals. As near as I can tell, hominds are unique among savannah
animals. Hence, to me, the "land theory" is disproven.
> AAS
> supporters keep trying to prove the AAS, when they should be listing ways
> to potentially falsify it. Furthermore, when claims are effectively
> falsified, they scream about elitism in academia.
Well as you can see, I do not think you effectively falsified
the claims (diving reflex excepted).
Once more. Again, the way to falsify the AAT is to find a fossil
in the 'gap' that clearly was not living in an aquatic environment.
I have been reading about the evolution of man for a while now,
and it strikes me that the "land theory" is just as protean as
you claim the AAT to be. First it was big brains and bipedalism
that went together (Darwin), then with the discovery of earlier
fossils it became tool use and bipedalism that evolved together,
now with Lucy et al tool use has a real problem. What explanation
will be taked onto the land theory next to keep the proto-homind
out of the water? :-/
> ps - regarding American crocodiles - they rarely occur on beaches in
> Florida, but if you look at the rest of their range, which includes most
> of the Caribbean down to northern Venezuela - they do elsewhere.
I told you. Then the AA's must have lived on a beach like a beach
in Florida:-) Of course any modern crococile on a beach is likely
to find itself a handbag so man may be the explanation :-)
> Thorbjarnarson had a monograph in the Bulletin of the Florida Museum of
> Natural History on C. acutus on the island of Hispaniola a few years back
> - I'll try to get the reference later.
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