Re: AAT

Elaine Morgan (Elaine@desco.demon.co.uk)
Tue, 04 Jul 1995 14:34:14 GMT

There has been a torrent of stuff lately under various headings
that all really relates to AAT. Some of it inevitably has been answered
before, but the enquirers have moved on and the answers have been
forgotten. But I would like to reply to some serious misrepresentations.

Jim Moore says that that "all" (sic) supporters of AAT claim that a
major reason for the evolution of bipedalism was that wading in water
helped to support the body weight. I do not know of anybody that says
this. He quotes one sentence of mine out of context. I was suggesting
weight support was a minor spin-off, an accidental advantage which
happened to make the business of walking on two legs (diffficult for a
beginner in any circumstances) one degree less difficult.

He says that another "major" reason we "all" use is that life in water
was safer. I don't know of anyone that says that. The whole drift of my
argument about b.p. is that in the early stages of adaptation to it it
is such an inept method of getting around that it would only have been
adopted under duress. In chest-high water there would have been no
option. I don't know of anybody who suggests that a gorilla would stand
up to paddle.

Most of the antiAAT arguments are based on arguments I have not used
for over twenty years. I do not propose that the ancestral ape decided
one day that life in water would be nice. I have given good geological
evidence, that at the time of the split and at the likeliest place for
the split their habitat was flooded, perhaps catastrophically, and
cerainly extensively. Somebody asserted that the proboscis monkey (which
lives in flooded forest) is "overwelmingly quadrupedal" in water. Well,
it depends on the depth of the water,
doesn't it? I have film of proboscis monkeys walking bipedally in
water, AND ON LAND.

Alex Duncan argues very reasonably that in the open spaces bwtween the
trees those hominids "that were most adept at moving from tree to tree
on the ground would have been selected for". Sure. And the most adept
primates at covering the ground rapidly are (and would then have been)
the quadrupedal ones. Four legs are faster than two. Stamina doesn't
come into it. Until you have learned to walk the first hundred
yards you cannot know that in a few million years you're going to
be good at the marathon. After five million years and extensive
remodelling of skelt[eton and muscles we are quite good at moving on
two legs- but we are talking about the ancestral ape. We have been twenty
times reminded that for an ape walking on two legs takes no more energy
that walking on four (no less either) Okay, but running on two takes a
hell of a lot more energy for an ape - something like four times - and
it is SLOWER.

Knuckle-walking is not something the apes adapted because it had any
advantages - it is because they have beome so adapted to a hook-on grip
for suspending themselves from the branches that they are physically
incapable of extending both elbow and wrist at the same time. i.e. they
are more specialised for brachiation than we ever became. The
intermembral index, even as early as Lucy, backs this up.

I cannot resist quoting from a new book by Daniel.C. Dennett (pub Simon
and Schuster) highly praised by Richard Dawkins, Jared Diamond, Edward
O. Wilson, et al. He says;

"During the last few years, when I have found myself in the company of
distinguished biologists, evolutionary theorists,
paleo-anthropologists, and other experts, I have often asked them just
to tell me, please, exactly why Elaine Morgan must be wrong about the
AAT."

(For three decades I have been praying that someone moving in the right
circles would do that)

He continues: " I haven't yet had a reply worth mentioning, aside from
those who admit, with a twinkle in their eyes, that they have often
wondered the same thing."

Wow!

Elaine



-- 
Elaine Morgan