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Re: bauplan convergence



At 10:02 AM 6/15/00 -0700, Betty Cunningham wrote:
I still put a vote behind the protofeather sexual display hopping thing
for wing development; which is niether trees up or trees down, really.
It makes more evolutionary sense to have a pre-flight-capable wing for
making pretty, that later develops flight-worthiness, than a post-flight
flipper developing flight-worthiness does...

I didn't say I thought it was viable - it just came closer than most other alternatives.


My own preferred *hypothetical* sequence is something like:
1. Development of protofeathers for a combination of insulations and display.
(essentially, self-reinforcing feedback), leading to:
2. Enlarged display/brooding feathers on the arms.
3. Development of a scansorial/arboreal lifestyle in a small form, allowing:
4. Co-option of display feathers as a parachute/proto-wing.
5. Elaboration of new function by natural selection for improved aerial
safety/agility.


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May the peace of God be with you.         sarima@ix.netcom.com