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Re: bauplan convergence



#4 -parachuting just doesn't mesh for me as a reason for developing
proto-flapping.  

Consider this; a glider wouldn't want to flap as it throws off stability
and control of a glide.  I picture the early aviators pumping away like
mad on their flapping machines as they leap off of cliffs and just
basically plummeting a lot (sure, weight was a major factor then, but
the flapping just didn't aid the plummett one dang bit).

A gliding animal wants fairly immobile wing positions to parachute
with.  A flying animal needs to flap and parachutes both.

An animal that is already flapping to attract females or to scare away
intruders is a prime candidate to have leaping out of trees or leaping
up in the air WHILE FLAPPING and thus accidentally discovering flight,
than a creature that simply leaps out of a tree with the intention of
getting to the ground. 

Gravity can get ANYBODY to the ground that leaps out of a tree.  

Gravity, air, and a little extra skin on the arms gets you parachuting.  

But parachuting doesn't require that you flap. 

-Betty Cunningham

Stanley Friesen wrote:
> 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.


-- 
Flying Goat Graphics
http://www.flyinggoat.com
(Society of Vertebrate Paleontology member)
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