home *** CD-ROM | disk | FTP | other *** search
- Path: sparky!uunet!tdat!tools3!swf
- From: swf@tools3teradata.com (Stan Friesen)
- Newsgroups: talk.origins
- Subject: Re: Creation Evidences
- Message-ID: <1657@tdat.teradata.COM>
- Date: 22 Dec 92 18:49:01 GMT
- References: <1992Dec13.130836@IASTATE.EDU> <1992Dec15.134757.3878@city.cs> <7970@tekig7.PEN.TEK.COM> <62899@mimsy.umd.edu>
- Sender: news@tdat.teradata.COM
- Distribution: world
- Organization: NCR Teradata Database Business Unit
- Lines: 84
-
- 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
-