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Re: Archie



>From: Scott <HORTON@BCRSSU.AGR.CA>
 > 
 >  I haven't made up my mind yet on the arborial vs. cursorial debate. But to 
 > keep
 > an open mind I must disagree with Mike's statement. If a large portion of the
 > animal's diet was indeed dragonflies, then partially developed wings can be
 > selected for in that it allows jumping higher or farther to catch the insects
 > in flight.

Two problems:

1. does this mode of hunting become steadily more efficient
as wing size increases?  Due to the particular arm movements
involved in this sort of hunting, it is not clear that a
continuous gain is made all the way to full wings.  (The motion
for catching prey is neither that of a flyer nor that of a glider,
so the aerodynamics is quite different).

2. The giant dragonflies were Carboniferous, NOT Mid Jurassic.
By the middle of the Jurassic, insects were, over all, quite
similar to what they are today.  Only a few major groups, such
as ants and bees, did not yet exist.

swf@elsegundoca.ncr.com         sarima@netcom.com

The peace of God be with you.