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




----- Original Message ----- From: "Mike Habib" <habib@jhmi.edu>
To: "DML list" <dinosaur@usc.edu>
Sent: Friday, September 26, 2008 11:56 AM
Subject: Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)




 Yes, clearly competitive exclusion can be powerful, but do we
really expect that the simple existence of powered flyers should
completely shut down gliders with limited powered ability?

Yes, I do. I take the lack of "gliders with limited powered ability" as implied support for this assumption.

The reverse may have happened at least once. No birds with significant soaring capacity seem to have evolved until after the demise of the pterosaurs (flap-gliders), after which they seem to have evolved very quickly. So, while birds (powered flyers) don't seem to have shut down gliders with limited powered ability (pterosaurian flap-gliders), the reverse may have happened, at least to the extent of blocking the powered flyers from expanding into the flap-gliding niche while the competition was still there. Note that I toss this out to demonstrate that the option is open -- I don't feel that we know that that is actually the cause, and I don't feel particularly strongly about it myself.
JimC