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

[don ohmes <d_ohmes@yahoo.com>]

--- 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 
ask...

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

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

Don