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Re: Origin of feathers
In a message dated 98-04-08 03:39:27 EDT, email@example.com writes:
<< Hence, a different thought: maybe feathers developed not as an organ
that _did_ something so much as an organ that _showed_ something --
i.e., a courtship or territorial display of some sort. >>
I still like the idea that pre-feathers appeared as a mechanism for excreting
excess sulfates (see ref in prior post), because this provides a compelling
rationale for their >initial< appearance. Pre-feathers >couldn't< appear
initially >for< display or >for< flight, for example, since these functions
didn't exist until the pre-feathers >had already appeared<. Only after the
pre-feathers appeared could they start to acquire various other functions, and
only then can natural selection act on them.
The idea is that the creature doesn't say, "I need to fly and I need pretty
colors, therefore I shall develop feathers." Rather, it is, "Hey, I've got
feathers. Now I can start flying and showing off."
Molting, incidentally, would be part of the excretory process, and is thus a
good candidate for the oldest retained feature of avian feathers.