Glideing, flapping

[tlford@ix.netcom.com (Tracy Ford)]

You wrote: 
>
>
>     The major disagreement I have with BCF is its avoidance of
>convergence; it seems to claim that any archosaur or near archosaur that
>may have flown or been arboreal had to be closely related to birds.  There
>is no shortage in the modern world  of gliding animals; mammals, frogs,
>lizards, and even snakes (!).  What is so hard to believe about gliders
>and tree dwellers evolving among the archosaurs numerous times during the
>Triassic, especially considering they otherwise don't seem have
>much in common?        


Why even have a glideing phase? Why not just go streight to flapping? Snakes, 
haven't developed wings, nor frogs, nor lizards, etc. If an animal glides well, 
why would it even have to start flapping.

To be even more contraversal, birds went from the trees down, while pterosaurs 
went from the ground up. I'm still under the subspection that pterosaurs never 
went into the trees (Boy, talk about your Heresies!!!)

Tracy