Jules Poirier lectures in British Columbia

[scott at home.com]

In <amg39.REMOVETHIS-07E97B.17255618092000 at newsstand.cit.cornell.edu>, WickedDyno <amg39.REMOVETHIS at cornell.edu.invalid> writes:
>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.
>
This is the evidence?


>What other intermediate stage could there be?

and

>And gliding is a useful adaptation.


All four separate origins of flight must have
had a precursor "intermediate" stage of gliding
because we can conceive of no other way to
arrive at flight from non-flight.

In each case of the origin of flight, gliding would
have been a useful adaptation on the way to flight.
The evidence for this is...

..we can conceive of no other way to arrive at
flight from non-flight.


Scott