|
|
Re: Holloway/Morgan
Ralph L Holloway (rlh2@columbia.edu)
Fri, 21 Jul 1995 23:10:49 -0400
On Thu, 20 Jul 1995, Elaine Morgan wrote:
> Whether we were right or wrong, I doubt if anyone would have dreamed of
> doing research in the 8o's and 90's into the eccrine glands of
> anthropoids if it hadn't been for us.
I am not sure about this. Perhaps you are right. But during the '60's
and 70's there was atremendous burst of interest in primates, both as
miniture us's and as phenomena worthy of study in their own right. When I
reread Montagna and Ellis 1963 I thought where have been all the newer
quantitative histological studies of this proble.? Where would Montagna
take us today? My point is I'm not at all sure that it was the AAH'ers
who have been the primary movers of such research. I would be more
willing to see the research as a natural development of the braod range
of interest in primates and human evolution.
Has there really been that much research into eccrine/apocrine glands
in the '80's and '90's?. I am not aware of very much, so bring me up to
date.
> So where do we stand? You suspect my followers of maximising the
> differences; I suspect yours of sweeping them under the carpet.There is
> nothing there, given good will on both sides, which intrinsically
> precludes arriving one day at a synthesis, at least concerning the data.
Like I stated in a previous post, the near genetic identity between
ourselves and chimps makes it apparent that a small bit of the genome is
devoted to the differences and that these are propbably regulatory. By
that, I meant by-and-large a lack of quantum leaps between the motrphologies.
The Eccrine/apocrine and sweating data is still in need of clarification
by both sides, but what I see here are very minor differences. If chimps
and gorillas are in environment with high dew temperatures, do they
really need to sweat to get rid of heat, as compared to humans where the
cooling gains are greater in less humid environments?
Webbing? Damned if I see much difference, and the cell loss during
embryology must be just about identical between pongids and ourselves.
Hair patterns? Brains? Now there is a real possibility of a sort of
quantum leap, but nothing suggests itself genetically except what could
be a very small set of regulatory genes.
Then there is the matter of how these similarities are accounted
for. My impression is that your side mostly treats these as convergences,
and most of us restrict convergent evolution to mean similar adatpational
designs between groups of organisms rather distantly related, i.e., as
mammals adapting to an aqueous environment with a streamlined body, i.e.
converging on fish-like body shape. Nothing that we have argued about
between AAH and standard Savannah/mixed is off an order of magnitude
suggesting convergent evolution, and without fossil evidence, I don't see
how one can refer to the "similariities" as aspects of true parallel
evolution either.
> And we differ on the time scale. You woudn't deny the differences are
> by now considerable.You would say they accumulated slowly by easy
> stages. A bit of genetic drift (we'll get down to those building bricks
> when I've had time to swot them up) the chance acquirement of behaviour
> patterns like reaching up to pick fruit or chipping a flint, some
> random mutation and a lot of feedback. Maybe millions of years between
> each item
I don't think I would say this, because I still am not sure what is so
different that allows you to claim that the "differences are by now
considerable". The next part is not attributable to me, because I don't
know of any fossil record for any of the pongids during the last 9-10
million years and what was around (aquatic or not) up to 4-6 million. Some
of the changes could have been "fast", i.e., by reasonably intense
selection, others might indeed be a result of drift, or even any number
of combinations. Evolution is usally "mosaic", so I would expect anything
but slow gradual change in all morphological aspects. (Sorry, have I
understood you correctly?)
> I would say with Hardy that possibly a whole clutch of them ,
> particularly the ones that make least sense, were acquired (or the
> potntial for them like speech was acquired) right at the beginning.
> That would tend to suggest a more catastrophic environmental change
> than the gradual minor shifts that would suffice for your scenario.
I'm sorry, but I am not following you here when you say"... a whole
clutch of them, particularly the ones that make least sense...".
> Both timescales are hypothetical and will probably remain so. I think I
> discern a pattern that you cannot recognise. Lke those wizards, some
> people can see it. In any case, I think it is healthy that each new
> fact that emerges should be tested against both possibilities. When
> there is only one scenario on the book, facts that fit it are acclaimed
> and inflated and those that do not are quietly ignored.
> I guess I have to agree with you here. You indeed discern a
pattern that I don't yet recognise (you mean the morphological,
physiological and behavioral concomitants of an aquatic adaptation,
yes?). I certainly agree that it is a good idea to look at each new (and
old) piece of evidence and test it with regards to its fit in any of the
hypotheses around, and that definitely includes AAH.
All best, Ralph Holloway.
|