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Re: Science feather strength debate



> On 11/4/2010 10:09 AM, Don Ohmes wrote:
>
> Also -- if some flightless birds retain asymmetrical vanes, while others
> don't, and those birds that do not have them are "further" from their
> earlier volant state -- then that would tend to support the notion that
> asymmetrical vanes evolve under flight conditions, would it not?
>
Non necessarily, because you may have assymetrical vanes appearing
before or together with flight. Someone knowing more about pennaceous
feathers in non-avialians may tell us if the assymetrical vanes are
actually derived with respect to symmetrical ones or not.