Re: Bipedalism and theorizing...WAS: Morgan and Creationists
John Waters (jdwaters@dircon.co.uk)
20 Sep 1996 01:53:21 GMT
Phillip Bigelow <bh162@scn.org> wrote in article
<323DCF0D.78B0@scn.org>...
> John Waters wrote:
> > JW: Thank god for the discerning amateur. (If it were not
for
> > the likes of Paul Crowley and John Hawks, where would we all
be?)
>
> I assume that this was sarcasm,
JW: It was not. Judging from your articles concerning the
Acquatic Equus, it seems
your conclusion here might be a consequence of (psychological)
projectionism.
> Nothing would change. Crowley and Hawks don't write the
research
> papers.
JW: Nor did Charles Darwin, but then he was only a discerning
amateur.
> J.W. wrote:
> > Only discerning amateurs can be unorthodox. ^^^^?
>
> Orthodoxy follows rules, it is true. But being
> unorthodox doesn't follow rules. >
JW: Only partly true. The Unorthodox may follow rules too.
Newton and
Einstein were partly unorthodox. So are most amateur and
professional scientists who introduce new concepts into the
world of
science. Or rather, they are perceived to be unorthodox.
Incidently,
do you agree with The Synthetic Theory? Must mutations be either
advantageous, or disadvantageous?
>
> > In respect of your last paragraph Paul, you seem to be
unaware
> > that evolution is usually a very slow process.
>
>
> This statement is a generality in search of evidence. The
theory
> of Punctuated Equilibria (of Gould and Etheridge) isn't, in a
> geological sense, a "very slow process".
JW: Etheridge?? Who he? Any relation to Niles Eldredge?
Who said anything about geology? My remarks concerned hominid
evolution. And while we are not on the subject, what do you
think of
Goulds assertions in respect of the sigmoidal curve?
> Australopithicenes didn't follow this scenario, John. Their
brain
> size was roughly the same as a chimpanzee, and their body mass
was
> also roughly similar to that of a chimpanzee.
> And Australopithicenes were actually a ways along the hominid
branch
> by that time. If anything, at the earlier node of speciation,
> the ratio of hominid brain size to body mass should have been
> even closer to that of the chimp/gorilla ratio.
> Only later (in Homo) did hominid brain size take a quantum
leap.
> <pb>
>
JW: To be consistent, (see my letters to Paul Crowland) the
period I am talking about is 4.5 to 7 Mya. This is generally
agreed to be prior to the Australopithicines. Nevertheless, I
would have expected the changes to have continued in the
Australopithicine period. If they didnt, it doesnt matter as
far as this initial hypothesis is concerned, because as you
rightly say hominid evolution was on the way by that time.
Your use of the term brain size to body mass suggests that we
are talking at cross purposes. In which case, it is probably my
fault for failing to repeat the statements I made in previous
correspondance. For this I apologise.
So, to recap. The significant elements of my previous
discussions concerned the relationship of the size of the skull
and the pelvic canal. It has nothing to do with brain size. It
is about the problem that a female has in trying to give birth
to a baby whose head is too large to pass easily through her
pelvic canal.
I made the point in previous correspondance that it was not a
question of the head getting any larger, but rather a case of
the body getting slimmer and slighter. At risk of being seen to
be inconsistent, I would point out that the same condition could
be achieved if the body stayed the same size and the skull got
larger. However, in the
latter case, there is no need for any increase in brain size. An
adaption to tougher foods could lead to larger teeth, jaws, jaw
muscles and their attachment points. Indeed, this development
took place in the case of A. Robustus.
You use the term roughly when talking of Australopithicine
Fossils. Fair enough. I have every sympathy with
paleontologists who have to try to decide whether a fossil
belongs to a male or female, child, adolescent or adult.
It is especially difficult in respect of early hominid
development, because the differences we are talking about here
would be very small. Millimeters not centimetres. Likewise, as
expressed in my letters to Paul Crowland, the effects would be
very small. Nevertheless, they could tip the balance away from
pure knuckle walking to semi-bipedalism.
Unfortunately, there is a dearth of fossil evidence in the
pre-Australopithicine period. So my hypothesis cannot be easily
tested by relating in to the fossil record.
However, the Australopithicines showed that a great diversity of
morphological development was possible, as the specie(s) adapted
to different kinds of environments. In this regard, in should be
noted that the increased jaw size evident in A. Robustus was
accompanied by an increase in brain size.
To sum up then. It is not a brain/bodymass question. It is not
about the brain getting bigger. It is about the foetal stage of
the brains embryonic period getting slower; and this leading to
an extension in the period of helplessness of the newborn
infant. The fossil evidence is scanty, and perhaps one should
not draw too many conclusions
from such limited evidence. But there are alternatives to
fossils. In this context, there does seem to be a relationship
between the embryonic and post embryonic development of the
foetus and babies, and the long term evolutionary development of
the species.
Meanwhile, until we have a complete, irrefutable answer, we must
take the facts as we find them and use the principle of Occam's
Razor to produce the best fit.
Endpiece. An extract taken from the Origins of Humankind Message
Board, http:/www.pro-am.com/www board2/wwwboard.html?
Ross Carter (namepara@mis.net)., replying to an article
submitted
by Robert G. Bednarik(aurawww@sli.unimelb.edu.au).
----- ^^^^^^^^^Thoughts and behaviour dont fossilise
Robert G. Bednariks reply: No, but theories on human evolution
do.
Nice one, Robert.
John Waters
John Waters is the author of "Helpless as a Baby",
a book concerned with general and human
evolution. It may be accessed at URL
http://www.dircon.co.uk/jdwaters/HAAB.htm
jdwaters@dircon.co.uk
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