More Morgan/Nicholls
Elaine Morgan (Elaine@desco.demon.co.uk)
Sat, 7 Jan 1995 11:35:22 +0000
Hi Phil (Chris?) This is fun, isn't it?
You wrote: "You are not trying to reconstruct a phylo-
geny." No, I doubt we'd disagree on the phylogeny. I'm
trying to address a simple question: Why is Homo unique
among the primates in such a bewildering variety of
ways? eg Functional nakedness, bipedality, prenatally
acquired fat layer, descended larynx,disappearance of
90% of apocrines, proliferation of sebum, psychic tears
accompanied by lump in the throat, moveable velum, eccrine
thermoregulation, vernix caseosa. etc. The conventional
response to most of which is : let's not talk about that.
Second simple question: in what kind of habitat
would these qualities be at a premium? If on the savannah,
why are they not common among other savannah mammals instead
of non-existent? To establish in what habitat they are at
a premium, is it not reasonable to enquire what other
creatures display these characteristics? In the majority
of cases the answer is: aquatic ones. This is a striking
fact. ST sems content to attribute it to the long arm of
coincidence. I don't think the arm of coincidence can
stretch so far,
.
> The vast majority of ALL fossils come from mud and silt.
Yes, of course. I plainly stated that fossil evidence
cannot prove the first hominids did not roam the arid
savannah. My point was that it certainly cannot prove
that they did (though that claim is often made or at
least implied)
> We know that hominids eventually moved onto the savannah
and that makes it reasonable to conclude that many aspects
of hominid morphology are a result of adaptation to the
savannah
Does it really make it reasonable? Even in respect of
aspects shared by no other savannah animal? The only species-
specific human trait that we can date from fossil evidence
is bipedality. As you say, many people now conclude that it
predated the savannah. But you then posit, without offering
any evidence for it, that all the other distinguishing
characteristics evolved millions of years later, just
because that would better fit your scenario. When I do a
thing like that you call it begging the question. I
submit that in this regard we are either equally innocent
or equally guilty.
> A theory or hypothesis is supported by evidence and not
by a lack of evidence for other competing hypotheses.
I couldn't agree more. The weakness of ST is that as far
as I can see it is not supported by any such evidence.
You on the other hand say "having read Scars of Evolution
I find no such evidence presented by you." I'm afraid this
inability to see the force of one another's arguments
is going to lay us both open to the attentions of the
deconstructionists :-)
> Recent dating techniques are pushing the times (of
South African fossils) back...
Okay. And recent discoveries are pushing the times of
the Afar fossils back even faster. It still seems likely
on balance that the initial trigger of speciation was
some environmental factor in Afar rather than in the far
South.
> All known hominids are found in mud and silt deposits
that border what at the time were savannahs.
The same is true of all known hippopotamids. Isn't that
interesting? (But "savannah" was not how Johanson
described Lucy's habitat. "Lush", he said.)
RE: Diving adaptation. I forget who said that this was
rubbish.
Let's get it clear. Any mammal dropped into water stops
breathing as a unconditioned reflex, and cessation of
breathing causes some slowing down of the heartbeat.
These reactions are more highly developed in but not
exclusive to aquatic mammals.
But: The striking capacity humans share with all diving
mammals and all diving birds is conscious control of
breathing. A dolphin can be trined to respond to a
command to retrieve different specified objects from
different depths in a training tank or pool. The amount of
air it inhales varies according to the amount of time
it knows it will need to be underwater.
Humans have the same kind of volitional breath control.
Apes do not. That is the sole reason why it is virtually
impossible to teach them vocal language however adept
they become at sign language.
Elaine Morgan
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