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Re: The ground-nowhere hypothesis on the origin of bird flight



On Fri, Oct 9, 2009 at 2:46 AM, Tim Williams <tijawi@yahoo.com> wrote:
>  At any given moment, the pro-avian can either be working with or against 
> gravity, not both.

Or neither. Like insects flapping their wing to propel themselves over
water surface as in Thomas & Norberg 1996. (Well not that birds do
it.)

Or pro-avians could alternate not only along evolutionary history, but
in different situations in them lives: some birds dive flaping their
wings.

[]s,

Roberto Takata