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Re: flying Archie

On Sat, Sep 23, 2006 at 05:05:17PM -0700, don ohmes scripsit:
> If evolution is the null hypothesis, Achie-style flight (whatever that
> was) was inferior to the modern style. Unless, of course, there has
> been some fundamental change in the global flight environment...

Doesn't follow.

You'd have to show that 'modern style' flyers displaced 'archie-style'
flyers *in the same environments* to demonstrate that.

What we've got is an environmental disjunction, with pronounced
bottlenecking across the boundary.  If the archie-style fliers continued
to prosper up to that disjunction, presumable what we've got is a
combination of bad luck and the environments for which the long-tailed
flight style was preferable not being available for a time as a result
of that disjunction.  (and all it has to be is long enough to starve to
death, as per Jim Cunningham's pterosaur extinction hypothesis.)

It's also quite possible that the 'not as good a flier, better runner'
tradeoff would be a net advantage in some niches --
roadrunner/secretary bird lifestyles come to mind -- and that those
niches didn't do so well across the K/T.

-- Graydon