I am sorry I hadn't replied earlier. I had so many e-mail and
snail-mail
issues going I couldn't do a proper job of research and response until
now. Your points certainly deserve a reply.
>I "posted" this reply to Glenn last Thursday, but this perfidious
>machine (sic) didn't let it go for reasons known best to itself.
>
>To refresh - I had asserted, too dogmatically, that taxonomic
>classification is arbitrary and he replied with reference to the
>shape of the "jaw."
>
>I replied - The shape of the dental arcade is entirely determined by
>the relative sizes of the incisors, canines and post-canine (cheek
>teeth) teeth. It simply is not true to claim that Australopithecines
>had a U shaped, or parabolic, arcade (as do modern humans). Some
>did, most did not. Many of them had cheek teeth larger than modern
>gorillas, that is, huge. Others had incisors larger than modern
>chimpanzees, that is, huge. All of them had canines shorter than
> modern
>male chimps or gorillas but still usually much larger than modern
>humans with regard to the amount of space they take up in the arcade.
> Large canines, large incisors and small cheek teeth typically
>produce the rectangular shape common to modern pongids. (The V shape
>that Glenn referred to is produced by large cheek teeth, small
>canines and tiny incisors.) Each of these tooth types has its own
>function and, so, is related to the habitual diet. Chimps consume a
>lot of fruit; gorillas a lot of tough herbivorous stuff. The canines
>of the males are used primarily for social display.
>
I must correct something I said and respectfully disagree with some of
what you are suggesting. First, my correction. I wrote that the Human
jaw was V-shaped. Actually it is parabolic shaped. There is a difference
although some authorities do call it V-shaped.
Now, To claim that the size of the teeth control the shape of the jaw is
somewhat misleading. Genetics controls the size and shape of both teeth
and jaw. Capuchins, macaques and baboons are all monkeys. They all have
box-shaped lower jaws (see Richard Klein _The Human Career_ 1989, p. 38).
Their size range varies quite a lot. A capuchin is maximum 22 inches
long; the macaque- 28 inches and the baboon up to 45 inches. The weights
of the macaque and capuchin are less than 18 pounds and the baboon up to
45 pounds. They are all omnivorous as is man yet the jaw shape differs.
Now the chimp, does not merely eat fruit. They are cannibals! They use
their canine teeth for eating the members of neighboring tribes. The
gorilla with his fiercesome teeth, is a vegetarian! But their jaw shapes
are the same--box-like!
>Paleoanthropologists claim the existence of at least three different
>species of Australopithecines none of which are assigned solely on
>the basis of shape of dental arcade.
I never claimed that the species were totally defined by jaw shape. My
point was that taxonomy was not a "black art". There are objective
features which can be discussed. Some have carried objectification to the
extreme and use multivariate analyses of the fossils. This is a technique
which makes numerous measurements of the shapes and ratios of various
parts of the fossils and then compares them. This is quite objective.
Measurments are measurements if taken on homologous parts of the fossil.
>My comment with regard to arbitrariness becomes relevant here. If
>one has a fossil (fragment) of an upper jaw (maxilla) one cannot, in
>good conscience or, I claim, in good scientific practice, name a
>species and proceed to describe it (with apologies to Cuvier). But
>this is exactly what was done in the case of Ramapithecus. This
>taxon has now been eliminated on the strength of opinion. If one has
>a fossil of a leg or, better, a pelvis it is easy to recognize
>bipedalism. This attribute, by the way, appears in the fossil record
>without ANY precursors. But this is sufficient only to recognize a
>stage, not a species. Hence the arbitrariness.
>
No one says that mistakes have not been made. They have. But mistakes
were made during the early stages of chemistry e.g. the phlogiston theory
or Aristotle's earth/air/water and fire. Mistakes were made in physics,
e.g. aether. But we don't now hold those mistakes up for ridicule in
order to reject the entire enterprise of chemistry or physics. We only do
this for sciences which threaten our interpretation of Scripture. I would
hope that the God of the universe who created it all would not need that
type of help.
>The criterion for accepting a species is reproductive isolation ("in
>nature"). At the risk of pointing out the painfully obvious, this
>information is never preserved in the fossils. I assert that the use
>of biological taxonomic labels for fossils is totally inappropriate.
>Better would be something like "Joe" or "Lucy" or "stage 1". The use
>of taxonomic labels for fossils (empirically) implies the acceptance of
> a specific
>theory of evolution - the neoDarwinian at the moment - and all the
>metaphysics that attend it.
>
>I apologize for getting "into" this. It is, however, important to
>realize that taxonomy cannot be done on an attribute by attribute basis -
>this form has a jaw shaped like that one so they are related. It simply
>does not work that way.
Ah but it does. All dogs are "related" to wolves because they are shaped
similarly! Their dentition, their jaws, their paws are similar. And some
of the actual evolution of canine form can be accomplished by matching the
characteristics of the various breeds.
glenn
Foundation,Fall and Flood
http://members.gnn.com/GRMorton/dmd.htm