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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)

--- On Thu, 9/25/08, Tim Williams <twilliams_alpha@hotmail.com> wrote:

> > Since many improvements in parachuting and/or gliding
> ability don't lead
> > toward the direction of powered flight, doesn't
> that create problems for
> > your scenario?
> If gliding did lead to flight in the ancestry of bats,
> it's clear that exceptional circumstances were involved.
>  So much for this route being "easy".   ;-)

It is not too surprising that there are no gliders currently making the 
transition to powered flight, considering the fact that they would have to 
invade niches occupied by birds and/or bats as they did so. Seems a lot to 

Competitive exclusion logically explains the paucity of gliding predators, too. 
And that in turn explains why most extant gliders are 'just moving from 

BTW, are there ANY cursorial vertebrates currently "moving in the direction of 
powered flight"?