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Re: FUCHSIA and the Ostrom Symposium Volume (long...)
Now for the real criticisms...
----- Original Message -----
From: "Williams, Tim" <TiJaWi@agron.iastate.edu>
Sent: Friday, August 09, 2002 10:58 PM
> > Fails to show (actually doesn't even attempt) why a sane winged runner
> > would suddenly begin to flap its wings at maximum speed. Why would
> > anyone do that, without knowing a priori that doing so increases speed
> > and/or leads to takeoff?
> Instinct, perhaps?
Instinct is a behavior that's hard-wired into the brain, and the wiring is
produced by genes, right? So, if not conciously, why should a sane winged
runner unconciously flap while running? Of course there's an easy
explanation: A mutation happened in the genes that produced the correct
wiring, and the descendants of that mutant had the advantage of being faster
and eventually of being able to take off. But that's beyond the testable. Of
course it might have happened, but you might just as well accept FUCHSIA :->
> Ostrom provided a step-by-step, gradualistic scenario on
> how a prey-catching forelimb might have changed over to a lift- and
> thrust-generating wing that carried the insect-eating biped into the air -
The step from the forward stroke to the downward stroke is missing, though.
(OTOH, the forward stroke looks just like what I can see in the video of the
vertically running bird... or this may be false memory. Gotta look again.)
> However, one
> may speculate that the inception of flapping - whether by a ground-running
> predator or a tree-climbing glider - was spontaneous and driven by
> rather than guided incrementally by the evolutionary process.
Just asking again: you mean it began to flap just so, because it was
basically crazy? In that case, see above. I can see how such a thing can
lead to a selective advantage, but it's not testable. If we can't find a
testable explanation, then I'll probably go with that nonetheless. But first
I'm trying to look for one.
> > Pronounces this on p. 266: "but this is a somewhat different motion than
> > the flight stroke". :-)
> [...] No author has claimed the two motions to be identical.
Yes. And none tried to explain how the change happened.