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To: fortheDeclaration
There are no miraculous "missing links." All populations are in transition, and thus all fossils are "transitional fossils."

But just for fun, here's an example of a fossil exhibiting characteristics of both fish and tetrapods:

A DEVONIAN TETRAPOD-LIKE FISH AND THE EVOLUTION OF THE TETRAPOD BODY PLAN

Does this meet your criteria for a "transitional fossil"?
31 posted on 05/26/2007 10:13:08 AM PDT by Boxen (Branigan's law is like Branigan's love--Hard and fast.)
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To: Boxen
but the origin of major tetrapod features has remained obscure for lack of fossils that document the sequence of evolutionary changes.

Here is the only true thing said in the article.

As always, your transitional fossils will be found out to be its own species, not in transition at all.

So everything is in transition is it?

Can you point to anything in existance that is changing from one species to another species?

41 posted on 05/26/2007 11:35:54 AM PDT by fortheDeclaration (We must beat the Democrats or the country will be ruined! -Abe Lincoln)
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To: Boxen

Tiktaalik to the rescue?
In the April 2006, issue of Nature, Daeschler, et al. reported the discovery of several fossilized specimens of a Crossopterygian fish named Tiktaalik roseae. These well preserved specimens were found in sedimentary layers of siltstone—cross-bedded with sandstones—in Artic Canada.4

Like the other lobe-fin fish, Tiktaalik was declared to be late Devonian (between 385-359 million years old) by means of a “dating” method known as palynomorph biostratigraphy. This method presumes to date sedimentary rock layers on the basis of the assumed evolutionary age of pollen and spores contained in the rock. Most importantly, the discoverers of Tiktaalik claim that it “represents an intermediate between fish with fins and tetrapods with limbs.”

Tiktaalik is a fish
Whatever else we might say about Tiktaalik, it is a fish. In a review article on Tiktaalik (appearing in the same issue of the scientific journal Nature that reported the discovery of Tiktaalik), fish evolution experts, Ahlberg and Clack concede that “in some respects Tiktaalik and Panderichthys are straightforward fishes: they have small pelvic fins, retain fin rays in their paired appendages and have well-developed gill arches, suggesting that both animals remained mostly aquatic.” 5

In other respects, however, Ahlberg and Clack argue that Tiktaalik is more tetrapod-like than Panderichthys because “the bony gill cover has disappeared, and the skull has a longer snout.” The authors weakly suggest that the significance of all this is that “a longer snout suggests a shift from sucking towards snapping up prey, whereas the loss of gill cover bones probably correlates with reduced water flow through the gill chamber. The ribs also seem larger in Tiktaalik, which may mean it was better able to support its body out of water.”

Without the author’s evolutionary bias, of course, there is no reason to assume that Tiktaalik was anything other than exclusively aquatic. And how do we know that Tiktaalik lost its gill cover as opposed to never having one? The longer snout and lack of bony gill covers (found in many other exclusively-aquatic living fish) are interpreted as indicating a reduced flow of water through the gills, which, in turn, is declared to be suggestive of partial air-breathing—but this is quite a stretch. Finally, what does any of this have to do with fish evolving into land dwelling tetrapods?

Are the pectoral fins of Tiktaalik really legs?
Before we get into Tiktaalik’s “legs,” it might be instructive to consider an old trick question. If we call our arms “legs,” then how many legs would we have? The answer, of course, is two legs—just because we call our arms “legs” doesn’t make them legs. The same might be said of the bony fins of Crossopterygian fish—we may call them “legs” but that doesn’t necessarily make them legs.

Shubin et al. make much of the claim that Tiktaalik’s bony fins show a reduction in dermal bone and an increase in endochondral bone.6 This is important to them because the limb bones of tetrapods are entirely endochondral. They further claim that the cleithrum (a dermal bone to which the pectoral fin is attached in fish) is detached from the skull, resembling the position of the scapula (shoulder blade) of a tetrapod. They also claim that the endochondral bones of the fin are more similar to those of a tetrapod in terms of structure and range of motion. However, none of this, if true, proves that Tiktaalik’s fins supported its weight out of water, or that it was capable of a true walking motion. (It certainly doesn’t prove that these fish evolved into tetrapods.)

http://www.answersingenesis.org/articles/am/v2/n2/tiktaalik-fishy-fish


42 posted on 05/26/2007 11:53:35 AM PDT by fortheDeclaration (We must beat the Democrats or the country will be ruined! -Abe Lincoln)
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