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Dinosaurs evolved into birds.

Baggins

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RichardT

All your link states is that the Curator of Birds at the Smithsonian hasn't had dinosaur-bird evolution demonstrated to his satisfaction. So what, there is a minority in the biological community that don't think it has been demonstrated, but the majority are happy with the evidence. I expect the unhappy minority to dwindle. Science isn't a religion people are allowed to disagree and have arguments, it is how science progresses.
 
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Frumious Bandersnatch

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RichardT said:

This nonsense comes from refuting evolution. I will leave the paleontology to other for now, though I have seen the Berlin Specimen of Archeopteryx and it is quite amazing. For now I will just address this one point.

Finally, feather proteins (F-keratins) are biochemically different from skin and scale proteins (a-keratins), as well. One researcher concluded:
At the morphological level feathers are traditionally considered homologous with reptilian scales. However, in development, morphogenesis [shape/form generation], gene structure, protein shape and sequence, and filament formation and structure, feathers are different. (24)

Keratins are something I know a little bit about. This is a rather classic case of out of context quoting.

Brush(Brush, 1996) is trying to argue that feathers may have evolved from directly from skin, the way hair apparently did, rather than from scale. While phi-keratins (called-F keratins in the link) are very different from alpha keratins, they are related to the beta keratins that are found in the skin of all reptiles and the scale of birds. The specific beta keratin in bird scales are also found in birds closest living relatives the crocodilians(Alibardi and Sawyer, 2002,Sawyer et al., 2000).

Feather keratins are shortened compared to scale keratins because of the deletion of an approximately 4,000 molecular weight repeating tripeptide(Gly-Gly-X) that followed a duplication of the original beta keratin gene.

Here are a few more quotes from the Brush paper.

Further, the proteins and genes of feather and scale ….are close enough to imply a common ancestor…….

All proteins in the family share a great deal of sequence similarity…

Subsequent to its appearance the gene was duplicated. One or more of the duplicates then incurred a deletion of the tripeptide portion. This provides a basis for two distinct size categories associated with the different tissues.

So by quoting out of context Sarfati has given the false impression that there is some mystery about the origin of feathers proteins when in fact it is well understood. There are still unanswered questions about feather evolution but recently considerable progress has been made, both in understanding the molecular basis of feather development and evolution and in find new fossils. Feather evolution appears to have occurred through changes in the regulatory genes that govern the interaction between epidermal and dermal tissue during embryological development. I have included a few references to current work on feather evolution and developmental genes but don’t have time for further discussion on the topic right now.(Chuong et al., 2000,Prum and Brush, 2003,Prum and Brush, 2002,Sawyer et al., 2005)


Reference List



Alibardi L, Sawyer R H. Immunocytochemical analysis of beta keratins in the epidermis of chelonians, lepidosaurians, and archosaurians. J Exp Zool 2002; (293): 27-38.

Brush A H. On the Origin of Feathers. J Evolutionary Biology 1996; (9): 131-142.

Chuong C M, Chodankar R, Widelitz R B, Jiang T X. Evo-Devo of feathers and scales: building complex epithelial appendages. Current Opinions in Genetics and Development 2000; (10): 449-456.

Prum O R, Brush A H. Which came first, the feather or the bird? Sci Am 2003; (288): 84-93.

Prum R O, Brush A H. The evolutionary origin and diversification of feathers. Q Rev Biol 2002; (77): 261-295.

Sawyer R H, Glenn T C, French J O, Mays B, Shames R, Barnes G L, Rhodes W, Ishikawa Y. The expression of beta keratins in the epidermal appendages of reptiles and birds. Am Zool 2000; (40): 530-539.

Sawyer R H, Rogers L, Washington L, Glenn T C, Knapp L W. Evolutionary origin of the feather epidermis. Dev Dyn 2005; (232): 256-267.
 
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LsforLove

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RichardT said:

It’s funny because it’s true and there is scientific evidence to back it up. Maybe you missed it when the Church rejected creationist claims and Intelligent designs claims anyone still have that link for Richard?
 
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LsforLove

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dlamberth said:
Just a small quibble...If I read this right, Birds evolved from Dinosaurs. Dinosaurs did not evolve into birds.

.

Grammatically and denotatively you are correct. However I would at least hope that we all can understand the connotative structure of the point and be able to discuss it.
Wonderful observation however.
 
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Dal M.

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RichardT said:
I did this more just for fun and to start up a riot :)

There's a name for people who do that, you know.

characters-trolls.gif
 
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