Re: Evolution of Bird Feather and Aerofoil

On Fri, 14 Sep 2007 13:17:58 -0000, UC <uraniumcommittee@xxxxxxxxx>
wrote in
<uranium-1189775878.777837.42140@xxxxxxxxxxxxxxxxxxxxxxxxxxxx> :

On Sep 13, 7:49 pm, John Harshman <jharshman.diespam...@xxxxxxxxxxx>
wrote:
UC wrote:

[snip]

After all, birds fly down from tress and up
from the ground. You could ask how did they get up into the trees to
fly down in the first place, but there are ways of crawling up. Any
adaptation that allows for "ground up" also contributes to "trees
down" and vice versa. I think the dichotomy is false. What might
contribute to "ground up" is smaller size (and weight).

The dichotomy is not false. The two proposed mechanisms requrie animals
that are ecologically quite different. Trees-down postulates an arboreal
glider. Ground-up postulates a cursorial predator.

I don't buy it. Any animal that is amall enough will have a selective
advantage toward flight, as there is less weight to deal with. Whales
and elephants need not apply. Bats and birds are all small, light
animals. Instead of thinking "ground-up" or "tree-down" we should be
thinking 'small' and 'light'.

Earthworms are more likely to evolve flight than squirrels?


Now one idea that is
not out of line with trees-down is WAIR, which you could look up.

WAIR? What is that?

http://jeb.biologists.org/cgi/reprint/206/24/4553.pdf

[snip]

.

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