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Re: If Dinosaurs Could Fly



Terry Jones wrote:

>evolved well before endothermy.  There is a logical evolutionary progression
>from scales (in ectothemic avian ancestors) to flight/contour feathers (in
>ectothermic early birds) and finally to downy feathers (in later, enothermic
>[ornithurine] birds).  In order to have insulatory feathers in the earliest
>birds they would have to appear intact out of the blue!!!
>
Here's a speculation which may be worth no more than a chuckle.  I've been
trying to think what feathers could possibly be derived from.  Its not easy
to see how a proto-bird could go directly from scales to something as
derived as a flight feather in one step, particularly if small, insulating
feathers were a more recent development.  How about quills -- like a
porcupine?  Is the term "quill" used for both porcupine integument and the
central shaft of a feather merely an accident of language, or could there be
some structural homology (or at least some functional homology)?  We've been
looking for Big Bird.  Maybe we should be looking for Sonic the Hedgehog.

  --Toby White