From: swf@tools3teradata.com (Stan Friesen)
Newsgroups: talk.origins
Subject: Re: Creation Evidences
Date: 22 Dec 92 18:49:01 GMT
Distribution: world
Organization: NCR Teradata Database Business Unit

In article <62899@mimsy.umd.edu>, folta@cs.umd.edu (Wayne Folta) writes:
|> 
|> I am tired of typing (I am not a touch typist), but I'll summarize the
|> rest. Basically he says that the brain cavity exhibits typically avian
|> hemispheres and cerebelum. And since it had totally avian wings, feathers,
|> and brain, and if it could fly, it is likely that it had avian lungs, heart,
|> and circulatory system.

Yep, Archaeopteryx had a avian type brain.  But, to a large degree, so did several
'coelurosaurian' dinosaurs (and even some 'carnosaurs').  Comparing A's brain to
modern reptiles is inappropriate when there are much closer forms available to
compare it to (Avimimus, Deinonychus, Compsognathus, Ornitholestes, ...).  When
this is done A's brain case does indeed fall out as intermediate between the
most derived reptilian brains and those of modern birds.

|> In the next chapter, he describes in great detail the avian lungs, which are
|> unlike any other lungs: flowthrough. This creates enormous difficulties for
|> a step-by-step evolution from a reptile's lungs. Even how the lungs form
|> during development are very much different from other lungs. And the fact that
|> there is essentially no variation in avian lungs increases the suspicion
|> that no fundamental variation of the avian lung is compatible with it working.

Balderdash.  It just means that this form is the most efficient, and once developed
any change reduces its effectiveness.  (Even a *slight* difference in efficiency
is sufficient for selection to operate).

And again, there is evidence for this kind of lung in *many* dinosaurs.
In fact the very term "coelurosaur" (for small carnivorous dinosaurs) refers to
an anatomical feature that, in modern birds, is associated with the one way lung.
That is it refers to the hollow bones, with internal chambers.

Once more, A., when properly placed in the sequence of forms, is, as expected,
intermediate in structure.

|> He then mentions other differences: heart, cardiovascular system, gastro-
|> intestinal system, syrinx, etc. which add up to an enormous conceptual
|> difficulty imagining gradual evolution.

Yep, and again all of this is based on comparing birds to Lacertilia (lizards).
Take for instance, the heart.  Crocodiles have what is essentially a functionally
four-chambered heart, almost exactly like that of birds (and different than that
of mammals).  The only real difference between a crocodile heart and a bird heart
is the existance of a *valve* between the two venticular chambers, a valve that
is only opened as a pressure equalization device during deep diving.

The transition from this form to the fully four-chambered heart of a bird is
almost absurdly small.  Just think a moment what happens to this valve in a
fully terrestrial form, that never needs to open it?  Just a small change in
development and, voila, the valve is stuck shut - a true four-chambered heart.

It is my contention that *all* dinosaurs had a four-chambered heart.
[Calculations of blood pressure and pumping requirements suggest that
the large sauropods *had* to have a four-chambered heart to support such
a long neck].

Hmm, as as I think on it, I believe that the crocodilian gastro-intestinal system
is rather more avian than that of other reptiles.

|>    Archaeopteryx is on the whole a point for the Darwinists, but how important
|>    is it? Persons who come to the fossil evidence as convinced Darwinists
|>    will see a stunning confirmation, but skeptics will see only a lonely
|>    exception to a consistent pattern of fossil disconfirmation.

Gah, this Denton guy seems to have no clue as to the nature of the fossil record.
Archaeopteryx *isolated*!?!?!?  Hardly!  It is so similar in most anatomical
features to certain small carnivorous dinosaurs that several experts actually
propose classifying it as such, *despite* the existance of flight adaptions
(such as true primaries).    This is *lonely*??  NOT!

Add in the Cretaceous toothed birds, and things become much more convincing.
|> 
|> So is disagreement on Archaeopteryx "drivel" or is it not as clear as the
|> previous poster made it out to be?

Yep, it is *still* drivel.  Denton is *not* a paleontologist, he is a lawyer. His
approach to evidence is legalistic, not scientific.

Try to find a paleontologist, one who *knows* the evidence, who makes a similar
argument.

-- 
sarima@teradata.com			(formerly tdatirv!sarima)
  or
Stanley.Friesen@ElSegundoCA.ncr.com