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Re: bauplan convergence




Stanley,
I see no big problems with such a sequence, but I believe protofeathers first evolved for either display or insulation, not both at the same time. I would suspect that display came first, and insulation would have eventually begun to reinforce that. Then the aerodynamic developments followed.
-----Ken Kinman
********************************************************
From: Stanley Friesen <sarima@friesen.net>
Reply-To: sarima@friesen.net
To: bettyc@flyinggoat.com
CC: dinosaur@usc.edu
Subject: Re: bauplan convergence
Date: Fri, 16 Jun 2000 18:23:14 -0700

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.


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

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