Re: Feathers

[ornstn@hookup.net (Ronald Orenstein)]

Thomas Holtz writes:

>In fact, the opposite is true - chemically and developmentally, feathers
>ARE modified scales.  As you note, not all the scales in a bird are
>modified, but then again, not all mammal sweat glands have turned to
>mammary glands, nor all mammal fur turned to vibrissae (whiskers).

Note that Alan Brush has recently speculated that feathers are not
homologues to reptilian scales, based on their chemistry (he sent me a draft
paper on the subject) so this matter is not clear-cut.
>
>First off, the question of pterosaur fur is much debated (as per recent
>discussions on the net).  Also, although flight feathers are fairly
>susceptible to damage, contours feathers are less so.

I think the question is the need for the complex structure of feathers, as
opposed to the rather simple one of hair.
>
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