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Re: more bird origins



In a message dated 96-10-03 20:17:46 EDT, Wabandco writes:

> By the way, skydivers do not fall like rocks; a great deal of
> control can be had over fall rates (I can range from roughly 95 to
> 130 mph, at will) and direction.  Once terminal velocity is reached,
> you'd be surprised how stable and manoueverable your body can
> become.

Right. I was exaggerating with a bit of hyperbole there.

Back in 1991, I suggested (Mesozoic Meanderings #2 first printing) that the
gliding-to-flying transition might have been managed by having two sets of
wings, one that evolved for gliding flight, the other for trajectory control.
As an example, I suggested an animal resembling _Longisquama_ in having long,
featherlike wings deployed from the back (modified dorsal scutes, if you
will) but with forelimbs acting independently as canard-like control
surfaces. The dorsal wings would hold the animal aloft, and the forelimbs
would be used for directional control. Later, as the forelimbs took over both
lift and flight control, the dorsal wings would vestigialize and vanish. At
the time, I considered this arrangement too elaborate. If, however,
theoretical problems with the "ordinary" gliding-to-flying transition cannot
be overcome, perhaps this is the way birds developed powered flight.