Replies: Duncan & Bigelow
Elaine Morgan (Elaine@desco.demon.co.uk)
Sun, 27 Aug 1995 14:52:58 GMT
A.D.
I should not have been facetious about Wheeler's work. Though I
don't agree with him I know it is meticulous, diligent, scholarly,
elegant. My send-up was a knee-jerk reaction because you went elitist
on me saying nobody worth mentioning doubted his thesis (i.e. anybody
who did was a rank outsider) I over-react to that stuff because I've
had *so* much of it and it is not an argument. However- sorry. Must do
better
Larynx: you summed up the position very lucidly. "If the descended
larynx is indeed associated with basicranial flexion .." then Laitman &
Liebermann have provided evidence of a late date for laryngeal descent
that scuppers the claims of AAT in this connection. But don't you see,
that "If.." clause is precisely what I question. B.c. flexion and
larynx descent are separate developments. There is no proof of any
connection. The fact they both feature in Homo sap. means nothing since
we are such anomalous creatures. It is like formulating a rule that
"Each and every mammal with an opposable thumb can talk". True, but it
casts no light.
Thermoregulation. This is great, we are now debating questions that
can be experimentally resolved. You say shaving a patch of a sheep's
pelt only makes him hotter because it is on his back.Anyone who wants
to produce an eminently printable paper can repeat the experiment
shaving patch(es) off its flanks. Take readings at 9a.m. noon,
and 3p.m. and measure the net effect on core temperature. Non-
invasive and very inexpensive.
You keep saying I haven't read things. I have not only read Wheeler's
account of convection, I.ve watched him expound it on t.v. But you
have to remember it was the ancestral ape, not man, which initially
found it expedient to stand up. Apes don't have very long legs like
people. The level of a bipedal gorilla';s head is only about ten per
higher than that of a knuckle-walking gorilla. The gradient of air
temperature between 5.5 ft above ground and six feet is nowhere near
20degrees C. Agreed the savannah ape would have had his hands on the
hot earth as well as his feet. On the other hand a pre-bipedal primate
generates some internal heat through the muscular effort involved in
balancing on two legs, whereas in us the posture is effortless. I would
say the net cooling effect would be close to zero.
Again we have a testable statement. If Wheeler's idea works in living
animals as well as in graphs, then a child or pygmy standing on the
savannah in the sun for say twenty minutes should get significantly
more overheated than a 6ft adult standing next to them. It only needs
two volunteers and a thermometer. Write up your findings expressing the
difference in degrees C and any journal worth its salt should be proud
to publish.
>What is the question to which you don't think he has got the
> answer?
The prehominid ape during its occasional ventures through the open
spaces of the savannah mosaic was confronted by the same
thermoregulatory problems as those confronting the savannah chimpanzee
today. This was pre-ramidus. It didn't even have an appreciably bigger
brain to be in danger of overheating.
Question: Why was it driven to adopt such an elaborate, circuitous,
and costly three- or four- pronged strategy (verticality + nudity +
sweating + fat layer) for solving a problem that is no hassle at all
for the chimpanzee?
pb. Hope you are not getting too badly scorched in the badlands of
Montagna - sorry, Montana (Freudian slip) Remember to stand tall;
they say it helps. I find it, as ever, chastening that nearly
everybody on the other side of this debate has done the hands-on,
data-gathering kind of science and I haven't.
> We don't compare the anatomy of humans with some idealised picture
>of what humans SHOULD be like.
Neither do I. I compare them with our nearest kin and speculate
about the differences. If that isn't a Darwinian approach I don't
know what is.
> We should be certain that we really are comparing like-anatomical
>traits (homologies) and not just convergent features that have no
>evolutionary connection
Should we? Why? Who says so? As long as we as clear about which is which?
Homologies are about taxonomy. I don't talk much about them because my
views on taxonomy are boringly conventional and sheep-like. I would
have nothing new to say that isn't being said better by people who know
much more about it.
Convergence is about what vicissitudes a species has gone through in
the course of or subsequent to speciation. I find that fascinating.
I have new things to say about it (right or wrong, they are new) and I
know things about it that a lot of experts have forgotten because they
are addressing different questions.
If you want to think only about homologies, it's a free country.
Whatever turns you on.
Elaine
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