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Welcome to the marvel of evolution (was Re: Moasaurus)





ELurio@aol.com wrote:

In a message dated 2/13/01 4:50:23 PM, twilliams_alpha@hotmail.com writes:

<< Ah yes. Feduccia's First Law of ABSRD. "If it has feathers, then it must
be a bird". >>


That's THE biological definition. To say that what is an old common sense
rule of thumb, is "absrd" is in itself absurd.

OK. But you see, a creature can be feathered and not be a bird. Here's how it works. Birds evolved from SOMETHING (most paleontologists say it is a dinosaur, others say it is not). That SOMETHING may have had feathers. Most likely it did. It doesn't necessarily make it a bird.


"Common sense" definitions don't always work, because it's a tad unscientific to decide if something should or should not be a "bird" based upon whether someone thinks it "just looks like a bird". If you're just arguing semantics, then I give up. But if you're arguing about what constitutes a member of the clade Aves, then we have to be a little more scientific. We have to come up with a definition and a diagnosis of the Aves, and then we have to carry out a scientifically-based analysis to see if a particular taxon is positioned inside or outside of the Aves. If you are intending to publish a paper entitled "_Caudipteryx_ is a bird because I just think it looks like one" then best of luck!

(Nurse, nurse, my pills!!!)

Does _Oligokyphus_ or _Chiniquodon_ look like a mammal? Does _Spalacotherium_ or _Triconodon_? Both probably had hair, but according to the current definition of the Mammalia, _Spalacotherium_ and _Triconodon_ are mammals but _Oligokyphus_ and _Chiniquodon_ are not.



Why do you think that many dinosaurs are depicted with naked scales?

Is _Sinosauropteryx_ depicted with naked scales? Not in the pictures I've seen.


Because
they're "reptiles."

Evolution happens. Reptiles become birds.

You can't just suddenly change a defintion in use for
hundreds of years and then call everyone who disagrees with you ABSRD.

Well, _Caudipteryx_ hasn't been known for "hundreds of years". Nor has _Rahonavis_ or _Microraptor_, so in point of fact, we need a NEW and SCIENTIFIC definition of the Aves. Sure, keep the old common sense definition of "bird" you read in Merriam Webster's. But in scientific discussions of the present day, we need to have a clear idea of what is and is not a member of the Aves.



Tim



------------------------------------------------------------

Timothy J. Williams

USDA/ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163

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