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Re: ABSRD BAND on Sinornithosaurus feathers



In a message dated 3/20/01 1:49:54 PM EST, twilliams_alpha@hotmail.com writes:

<< George Olshevsky wrote:
 
 >Evolutionarily speaking, an
 >animal cannot know that feathers will be good for insulation until >after 
 >it
 >evolves them; thus insulation cannot be the >reason< for the evolution > of 
 >feathers.
 
 Why not?  Even a microscopic layer of peach-fuzz-like integumentary 
 structures would act as a heat-trapping surface.  The seeds are sown for 
 further selection. >>

Maybe it wasn't a layer, just a sparse growth of peach fuzz. But--if you did 
have a mutation that gave you a layer of peach fuzz, then it could have 
served as insulation provided the animal was already warm-blooded enough to 
need it. If it were a cold-blooded animal, however, any insulatory effect of 
the peach fuzz would have been detrimental, since it would have kept ambient 
warmth from reaching its body.

I don't count insulation out, but it does require a special kind of animal; 
the sulfate excretion effect would not, assuming that all animals must deal 
with sulfates in some extraordinary way (which I'm not entirely convinced is 
the case).