Re: AAH update (was: Bipe
Dewi Morgan (D.Morgan@brad.ac.uk)
30 Jun 1995 12:16:54 GMT
j#d#.moore@canrem.com (J. Moore) wrote:
>Pa> The pack hunters, such as the wild dog and hyena, fill the "exhaustion
>Pa> predation" niche. Lions fill the ambush niche, to an extent. Was there
>Pa> room for a 10 mph weaponless bipedal ape to go pack hunting on the
>Pa> savannah? Doesn't compute for me.
>If you're going to talk about a transtional hominid, perhaps you could
>try using some sort of example that actually has something to do with
>how that hominid lived. Big game hunting seems to have begun no sooner
>than at least 5-8 million years *after* the split from apes.
So we hunted the little fluffy rodents? How could we? They are far too cute!
But, yes, I agree, big game hunting was well out of our league back then, and
the savannah theory is a poor straw-man, pitifully easy to knock over. If the
AAT is to be taken seriously it should compete with the more modern view of our
evolution.
So what did we hunt?
AFAIK (not that I have checked this, or anything), there are no species of
human which hunt without weapons. Even rabbits are beyond us. Okay, so a lucky
dive might get you one, but we are very poorly adapted to such techniques.
So maybe we were tool users to an extent, in that we chucked things at the
animals, or thwacked them? Quite possible.
Perhaps we were mainly herbivores, and only ate animals when we did get a
'lucky dive' onto a rabbit. More likely, this seems to fit out physiology a
little better. Possibly a combination of tool-usage for the hunting and
herbivorous for the rest?
This still does not explain any of our features, but it is at least a lifestyle
that a human could be expected to survive with, if not be perfectly adapted to.
Would you accept this as a viable strawman... er I mean 'working hypothesis'?
>Pa> >different microhabitats were available. A. boisei is found in
>Pa> >depositional environments that are indicative of wetter habitats than
>Pa> Which leads back to the $64k question. If bipedalism wasn't a savannah
>Pa> adaptation, what was it?
>Why don't you just *try* reading some semi-current theory? Get rid of
>your "treeless, waterless savannah" fixation and work with something
>more accurate. You give some evidence above of knowing that the treeless,
>waterless savannah you're using as a strawman versus the AAT is not
>accurate.
So, why =did= we go bipedal. From what I have so far heard it was a combination
of several forces which finally made us become bipedal.
First, we were reluctant to come down from the trees, but as they became
scarcer, we did shamble about on the ground, and we held onto things like
nearby branches to keep ourselves stable, as we were used to in the trees.
This caused bipedality, which was reinforced by sexual displays. We found that
when we did venture out into the sun this was a good preadaptation to coping
with the heat, which we then built upon with sweat glands, nakedness,
subcutaneous fat, and so forth.
>Pa> Display? No sign of sexual dimorphism.
>Perhaps you could try using complete enough sentences to make
>intelligible thoughts as well.
Don't pick on people's grammar, it is unbecoming of.
There is a certain amount of sexual dimorphism, visible mostly from the front
when standing (all statements are relative to the other gender, not to other
apes):
Females: Males
little body-hair lots body-hair
breasts no breasts
vagina penis
fat placement around the hips/thighs fat placement around the stomach
short tall
So, yes, we can have a workable theory that bipedalism was reinforced by sexual
displays.
[Note to americans: Quoting, or even reading the above might break that weird
new ruling your congree passed about pronography over the internet. Sorry about
that.]
>Pa> Temperature Regulation? But bipedalism didn't evolve on the savannah.
>You mean your "treeless, waterless savannah"?
Everyone but us AATers believes that the apes evolved in the place that is now
african savannah. So, our hypothetical 'working hypothesys' will have evolved
there. We now know that at this time it was a mosaic of habitats, so our
protohuman will be designed to cope with this mosaic.
>Pa> Speed? A new-born Gnu can out-run a mature human. You need a great 800m
>Pa> time to survive on the savannah.
>You think all animals which don't live in the deep forest, who instead
>live in semi-open savannah mosaic woodlands, can run as fast as
>antelope?
I think everything upwards of a mouse is too fast for a human. But for the sake
of argument I will say that there are a LOT of dodos and similar shambling
about on the savannah, so chucking rocks or thwacking them with sticks provides
an ample food source when combined with roots, berries, nuts, fruits, grubs,
tender leaves, certain seeds, blossoms, and of course miscellaneous frogs,
crabs, shellfish, etc as might be caught near streams.
Since there was an ample nearby water supply we can assume that there was no
problem getting as much water as was necessary to maintain sweat-cooling using
as much water as was necessary.
>Pa> Tool carrying? Bipedalism predates tools.
>Actually unlikely; you are confusing "stone tools" with "tools". Again,
>there's been *some* writing done on human evolution in the last 30 years.
Bipedalism predates tools, and no literature I have heard of denys this, but it
may well not predate improvised implements. The difference being, a tool is
something created to do a job, an implement is something around that does the
job just fine.
Our hypothetical protohuman was using gurt big thwacking branches on dodos.
>Pa> Food gathering? Lots of problems with disadvantageous intermediate
>Pa> forms.
>The non-existent "law of disadvantageous intermediates" again. Give it
>up, Pat; it doesn't exist.
Indeed. So out hypothetical protohuman could sling a brace of dodos over his
shoulder and shamble back into the trees where his dutiful spouse is waiting
collecting fruits. He makes his bipedal display, she hands over all the fruit,
and he magnanimously sheres it with her.
Okay, the social structure might be different, but that will do for the time
being.
>At any rate, leopards, except possibly in deep forest, do not "hunt from
>trees". Even a little study, or just casual watching of nature shows on
>the tube, would tell you that leopards in African open woodlands and
>savannah, hunt "from" the ground, and usually then carry their prey up
>into trees to get away from obnoxious prey-stealing beasties, such as
>hunting dogs and hyenas.
But not humans.
This was a good reason for the protohuman to base his society around the trees,
and only shamble out when the sun was not too high, to thwack a brace of dodos
and bring them back. There was also plenty of fruit and water (since the trees
would tend to be around water).
And if leopards etc came towards the trees, lookouts could scream, everyone
would jump into the trees and pelt the leopard, and the leopard would be driven
away without danger to the protohuman.
In fact, it is possible that he would shamble out when the sun was at its peak,
when all the predators were having their siesta, and hence a much safer time.
The prey would also feel less like running away at these times.
This gives a more logical reason for the wierd heat-regulation system
(bipedalism is only really an advantage at midday, we sweat far too much, but
then at midday we would have to, we have hair on our heads which would only
protect us at midday, etc)
So, would you say that our hypothetical protohuman, whom I shall call
australopithecus strawmanicus, is a valid contender, representing the latest
theories?
Are there any extra bits you would like to add? Any bits that do not fit with
the latest theories?
In particular, you need a reason for our lack of hair. Or you could deffer that
until later, when we started wearing clothes (no matter that there are tribes
that have never worn more than a loincloth). I guess it could be part of the
bipedal display bit.
Seriously, I am interested to know just what IS considered 'state of the art'.
--
- D. http://www.brad.ac.uk/~dmorgan/
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