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Re: Archaeopteryx and Flight
>From: NEIL CLARK <NCLARK@museum.gla.ac.uk>
> Why? Why should there have been any evolutionary pressure to
> develop flight at all?
Well, to start with, flight is metabolically expensive.
So expensive that it is often *lost* in island species.
> Within the range of intraspecific variation, there
> may have been an extreme morph that allowed for flight. Due to the
> lack of competition in this area, the morph was able to alienate itself
> further from the non-flighted morphs especially after the demise of the
Pterosaurs did not start to decline until *after* birds evolved.
In fact it is reasonable to conclude that it was competition with
birds that gradually eliminated most pterosaur groups.
[The last pterosaur groups, in the Late Cretaceous, were very
specialized, and invariably large - all of the small, generalized
insectivorous types had died out by then].
The peace of God be with you.