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Re: Why insulation = endothermy



Jonathan R. Wagner wrote:
<snip>
>         Easy response:  Because selection pressure related to flight causes
> the contour feathers to develop, and retain, a rachis, and when this
> pressure is removed (in flightless birds), the rachis may degenerate.
>         Please consider this argument before you carry on with this course
> of argument.  I do not believe that an argument of the complexity Stan poses
> (no matter how good the argument is) is necessary to resolve this issue.
>         Wagner
>Forgive my confusion, but this sounds very similar to what Stan said.  So what 
is your problem with Stan's post?  He didn't actually say anything 
complicated.  It seems to me that he said that feathers could have developed 
for insulation, then been adapted for flight.  Afterwards, selection pressure 
for this adaptation governed the current shape of the body feathers.  You 
added the bit about them degenerating in flightless birds but this is by no 
means exclusive to Stan's comment and in fact fits in nicely with it.  So I 
repeat, what's your point?  Have I misinterpreted something here?

Joe Daniel
jdaniel@aristotle.net