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Re: bipedalism and AAH
Phil Nicholls (pn8886@thor.albany.edu)
13 May 1995 04:13:05 GMT
patdooley@aol.com (Pat Dooley) writes:
>Um> In <1995May4.151403.2084@arl.mil> Troy Kelley <tkelley@hel4.brl.mil>
>Um> writes:
>
> << deletions>>
>
>> Actually, as Phil Nichols has pointed out (repeatedly!) in this
>> newsgroup, actual tests with chimpanzees has demonstrated that even for
>> those knuckle-walking apes, bipedalism is no less efficient a mode of
>> getting around. So the entire above argument is meaningless; the
>> question has been answered by scientific experimentation.
> How do these experiments measure efficiency?
Why not read the article, which I have cited about 10 times now.
Why do you continue to take positions on things without
getting the necessary information first? You have you don't
trust my citations. Fine. Call my bluff. What are you
waiting for? We have been going at this for more than a year
now.
> It may be that for foraging, chimpanzee style bipedalism
> (which is very different from true human bipealism) may be
> as energy efficient as quadrupedalism. I tend to doubt that
> becaus evolution maximises efficiency and we don't observe
> chimpanzees favoring bipedalism over their usual modes of
> foraging locomotion.
Again, read the article. If you are unwilling to deal with
the data then just say so.
Evolution doesn maximize anything. It selects what works best
out of an available pool of variation.
> Another important measure is speed, as in, how quckly can a
> chimpamzee get to a tree if threatened by a predator? The fact of the
> the matter is that in such circumstances, chimpanzees do not favor
> bipedalism.
Let's just deal with facts, shall we? Undoubtedly there was
predation pressure since there were predators.
Australopithecus afarensis shows evidence of extreme sexual
dimorphism. I we assume that protohominids were also
sexually dimorphic (a reasonable assumption given the fact
that all of the great apes are sexually dimorphic) then we can
also conclude that they were highly social since sexual dimorphism
and sociality are highly correlated in primates.
How do social primates respond to predators? They don't run
away. When baboons in an acacia tree spot a predator they
don't stay in the tree, they actually climb out of the tree to
meet the threat. I have personally observed male baboons
chasing away cheetahs.
When baboons move across the savanna the troup is organized in
such a way to defend against predators. Alpha males, females
and the young are in the middle, surrounded by a "fence" of
peripheral males. A predator may pick off a peripheral male
but then it has to deal with the alpha males who move forward
to engage the threat while the females and young fall back.
Now protohominids were not baboons and were, at least at
first, only making brief forays onto the savanna, possibly at
noon when most predators were inactive. I have no doubt that
when they did move out to forage they were organized and used
that social organization to reduce predation pressures.
Um> Shoreline habitats have their own share of predators, particularly
Um> with the extremely aquatic lifestyle often proposed by AAH
Um> proponents...sharks etc.
> Strawman argument. Sharks have been around for hundreds of
> millions of years and thousands of terrestrial species have
> made the transition to an aquatic existence during thatr
> period. Obviously sharks did not stop proto-whales,
> proto-dugings, or proto-penguins making the transition from
> land to water. Even today, when millions of human beings take
> to the sea, the shark kill rate is about on a par with
> lightening strikes.
By that same tokoups and
terrestriality, indicating that large agressive males and
social groups are an adaptation to predation pressures.
[deleting repetitive arguments about predation and
"nonadvantageous intermediates"]
>> In any event, Caroline Pond (who is acknowledged as a
>> leading edge expert on fat and who Morgan cites as support of
>> her views even though Pond's work directly and explicitly
>> contradicts the AAH) has shown that human fat distribution is
>> like terirestrial primates:
> Pond does nothing to explain the wide disparity between human
> fat levels and the primate norm.
Now are you basing this on the fact that you have read Pond's
work?
> So far as I can see, her contradictions are little more than
> assertions.
Again, what are you basing this on? Why do you so quickly
dismiss research before reading it?
>> "The sparse data on the 'natural' distribution and
>> abundance of adipose tissue in primates show that the basic
>> anatomy of human adipose tissue is similiar to that of
>> terrestrial monkeys, and so was probably inherited directly
>> from their primate ancestors."
> Of course it was inherited from their primate ancestors. It
> wasn't going to be inherited from their feline ancestors :-).
The point, is that it is a product of COMMON DESCENT (i.e.
homology) and not CONVERGENCE (which is what the aquatic ape
theory maintains).
>> "Anatomical, ecological and biochemical information provides
>> no evidence that the distribution of adipose tissue in modern
>> humans has evolved as an adaptation to thermal insulation, as
>> required by the Aquatic Ape Theory, or as protection from
>> mechanical damage."
> Oh, so perhaps Pond can tell us why it did evolve, along with
> all the other human oddities.
She doesn't have to. Science works by proposing hypotheses
and then trying to disprove them. I have taken on bipedalism
and sweating and shown that they are not oddities at all and
that they only seem odd to folks who don't know much about
primate anatomy and who don't have a good grasp of
evolutionary biology. Now we see that the same holds true
with regard to fat patterns.
--
Phil Nicholls "To ask a question you must first
Department of Anthropology know most of the answer."
SUNY Albany -Robert Sheckley
pn8886@cnsunix.albany.edu SEMPER ALLOUATTA
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