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Re: bauplan convergence
At 02:25 AM 6/17/00 -0700, Scott Hartman wrote:
Gravity can get ANYBODY to the ground that leaps out of a tree.
Gravity, air, and a little extra skin on the arms gets you >>parachuting.
But parachuting doesn't require that you flap.
Actually, while the term "parachuting" is bandied about by many when
discussing incipient levels of gliding, this usage is
innappropriate. Balda et al. (1984 Archaeopteryx conference
volume)provide a more aerodynamically correct definition of parachuting
as a method to slow descent using only drag (or at least where lift is
negligable). Animals that can glide at a measly 45 degree angle from the
horizontal are still creating lift at an impressive 70% of body
mass. Few, if any animals qualify as parachuters (although perhaps
flying frogs are an exception?) That's why flying squirrells and snakes
have flat bottoms but round(er) tops.
I am aware of the difference. I was thinking that drag-based reduction of
fall rates might precede the more specific adaptations establishing lift
May the peace of God be with you. firstname.lastname@example.org