Jules Poirier lectures in British Columbia
WickedDyno
amg39.REMOVETHIS at cornell.edu.invalid
Mon Sep 18 17:25:54 EDT 2000
In article <39c681a0_4 at news1.prserv.net>, scott at home.com wrote:
> In <8q44v4$g3b$1 at news.duke.edu>, mturner at snipthis.acpub.duke.edu (mel
> turner) writes:
> >In article
> ><amg39.REMOVETHIS-AAA43C.23363617092000 at newsstand.cit.cornell.edu>,
> >amg39.REMOVETHIS at cornell.edu.invalid wrote...
> >>In article <39c58d4f_1 at news1.prserv.net>, scott at home.com wrote:
> >>> In
> >>> <amg39.REMOVETHIS-62773D.21591816092000 at newsstand.cit.cornell.edu>,
> >[snip]
> >
> >>> >> 14.Describe one insect that was transitional between a non-flying
> >>> >> insect and a flying insect.
> >>> >
> >>> >A gliding insect.
> >>> >
> >>> Amazing!
> >>>
> >>> So not only is flying a convergent feature,
> >>> but so is the actual transition from gliding
> >>> to flying.
> >
> >How do you get "convergence" from that? As far as we know, flight in
> >insects arose just once, in the early ancestors of the huge group
> >Pterygota. He's just saying that the origin of insect flight would
> >have involved a gliding intermediate stage [much as it would in the
> >three separate origins of vertebrate flight].
> >
> That's my point.
>
> Four separate origins of flight, and all
> arrived at by the exact same intermediate
> stage. Amazing.
What other intermediate stage could there be? If you don't quite have
enough wing surface to fly, what can you do? Well, glide, of course.
And gliding is a useful adaptation. Not quite as useful as true flight,
in general, though.
--
| Andrew Glasgow <amg39(at)cornell.edu> |
| SCSI is *NOT* magic. There are *fundamental technical |
| reasons* why it is necessary to sacrifice a young goat |
| to your SCSI chain now and then. -- John Woods |
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