Re: Alex's gibbon-like CA

Phil Nicholls (
Mon, 13 Nov 1995 16:21:45 GMT

Paul Crowley <> graced us with the following

>In article <48587m$>
> "Phil Nicholls" writes:

>> Gee, I thought we were talking about the origin of bipedalism, in
>> which case we are not talking about hominid speciation at all but
>> rather the hominid-pongid divergence which would have been pongid
>> speciation when it occurred.

>This is sheer bad thinking. It's the best way to confuse the issue
>thoroughly. Even IF it was true (and I'm pretty sure that the odds
>against it are zillions to one) it's a bad way to try to sort the
>problems out. I've never seen it before . . . . . . so I think we
>can safely forget it . . . . . Phew!

The common ancestor of modern apes and modern humans would, if alive
today, be classified as an ape (pongid). Therefore the speciation
event tha produced the hominid lineage would have initially been
pongid speciation. Hominid speciation does not occur until after the
hominid lineage has been established.

>> In any case, I am indeed trying to focus on the origin of bipedalism.
>> In seeking the origin of bipedalism it is wise to look at modern
>> primates and try to understand when the resort to bipedalism. When do
>> monkeys and apes walk upright, under what circumstances?

>It's one way to consider the matter. That's all. One way. You
>should also try a few others: like "What special niche could the
>protohominids have occupied?" or "What benefits could justify the
>enormous costs of becoming secondarily altricial?" or "How could
>these creatures survive without climbing trees at night?"

Looking at primate bipedalism is a place to start, because it allows
us to speculate about your second question. It shows us that
bipedalism was not the anomalous behavior Morgan claims it to be. IF
we look at other primates we notice that some primates cannot be
quadrupeds on the ground. This is interesting because it places a
historical constraint on locomotor behavior if protohominids were
suspensory feeders similar to gibbons. Bipedalism permits them to
expand their range and thus their resource base. Remember that the
forests didn't shrink overnight. The distance from one resourse
patch to the next increases and as it does so the distance
protohominds must cover to reach them also increases. Selection
favors more effective bipedalism because this does not interfer with
the suspensory adapation used when in the trees.

>Why are these mundane questions ignored by the PA community? That
>is what I find so deeply puzzling. Why do you all stick in that
>ghastly rut of looking at how and when chimps or gibbons stand?
>It's been worked to death. Ain't you got no imagination?

Now you see, this is how I know you have never bothered to read any
"standard PA" because your questions are not ignored. Most
hypotheses about the origin of bipedalism are provided in the context
of exploiting a new niche. You question about surviving at night
without climbing trees, for example, shows you are unaware of the
evidence that strongly suggests Australopithecus afarensis was able to
climb trees. As to becoming secondarily atricial I see no reason to
believe that this occurred early in hominid evolution. As a matter
of fact, if the expansion of the hominid brain occurred as a result of
neoteny then this would not have occurred until 2 million years ago,
at which time hominids were firmly established on the savannah and
using tools.

You see, Paul, the thing that irritates me about AAH folks is that
they make these sweeping statements about evolution and "standard PA"
without every bothering to look into the what "standard PA" really has
to say on the subject.

Now I don't claim to have all of the answers and most of the standard
hypotheses have limitations and problems. We really don't know why
hominids became bipedal nor arre we likely every to know with any
certainty. Imagination is as useful in science as it is in fiction
but in scientific explanations imagination is constrained by the
available evidence. Paleoanthropology is a science. We have to
stick to the evidence. We cannot invoke acts of God, little green
men or mythical aquatic apes.

Phil Nicholls
"To ask a question you must first know most of the answer"
-Robert Sheckley