Re: Flight again (was Re: The Lizard of Oz)

["David Marjanovic" <david.marjanovic@gmx.at>]

> David Marjanovic
>
> >IMHO the first is rather improbable because a jump from such a low height
> >lasts too short for selective pressure for steering structures to
occur --
>
> More improbable than underwater swimming?
>
> It wasn't just for steering.  It was for stability in landing - so the
> little predator didn't topple over when he hit the ground.  That's one of
> the functions of modern bird wings.

I can't imagine a selective pressure for that... Basal pygostylians (and
even oviraptorosaurs) have increased the number of sacral vertebrae,
apparently for stability, and non-pygostylians had reasonably long tails
that put the center of gravity in a more stable position. And birds don't
parachute to the ground, they flap vigorously when landing to reduce their
speed and thus their kinetic energy.

> >A testable opinion of mine that has AFAIK not been tested: Downy feathers
> >are much too short and not stiff enough to exert measurable drag.
>
> Why do tennis balls have fuzz?

Good argument. But the fuzz seems not to slow down the tennis balls
significantly, and the effects of spin-induced drag -- flying in curves and
such -- can be achieved equally well with a smooth soccer ball.

> >Feathers for S excretion --> for insulation --> wings and maybe
semilunate
> >carpal for brooding --> underwater flight, tail feathers for steering,
wing
> >feathers slowly more asymmetrical --> flight in air? Lots of exaptations
> >here.
>
> Sulfur exceretion?  Underwater flight???  Those poor proavians - what they
> had to go through just to achieve powered flight.  Even the Wright
brothers
> never had it so bad.

Hey! They didn't want to achieve powered flight! This is evolution!
After all, the origin of tetrapods was a quite similarly complicated affair.