Re: Origin of feathers

[Thom Quinn <swo@execpc.com>]

Dinogeorge wrote:

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....Molting, incidentally, would be part of the excretory
process, and is thus a good candidate for the oldest retained feature of
avian feathers.

Thom:
This is a interesting idea, but begs the question of cost-benefit
ratios. Building pre-feathers would be energetically expensive. Would
just the excretion of excess sulfates be enough of a selective force?
Assuming that the non-feathered ancestors had the proper machinery to
excrete sulfates what would make pre-feathers a better mechanism? Can
the energetic costs of the pre-feathers be outweighed to make this a
selective advantage? I think that this might be a uphill argument.

Thom Quinn