RE: FLIGHT & CATS

["Tracy L. Ford" <dino.hunter@home.com>]

Subject: Re: FLIGHT & CATS


Mark the illustrator (SNOWFL96@aol.com) wrote:

>I think the tree-down version is much more correct. There is so much proof
>for this theory like... flying snakes, squirrels, frogs, marsupials, and of
>course, lizards.


I would agree that the "trees-down" scenario is more likely than a
"ground-up" for the evolution of avian flight, but for different reasons
than the one above

The above list of parachuting or gliding vertebrates (and there are many
more)emphasizes the prevalence of aerial locomotion among arboreal
vertebrates in order to get from tree to tree (or from branch to branch, or
from a tree to somewhere else...).  For example, skin membranes (patagia)
supported by the fore- and hindlimbs and designed for aerial gliding evolved
probably more than half-a-dozen times in mammals alone.<<
Where is the glenoid in gliding squirrels and lemurs? Is it high on the body
like birds? I was thinking of going to the San Diego Zoo and trying to get
some of the handlers to show me. Maybe soon.

>>*But*, there is no compulsion to believe that birds passed through such a
passive gliding stage.  I would argue (and have argued) that birds did not.
Remember, all the above critters are quadrupeds (except for "flying" snakes,
of course).  Birds are bipeds, and I have no doubt their immediate ancestors
were as well.<<
Quite right. Good gliders will stay good gliders.

>>The suite of anatomical features (integumental and osteological) present
in
those theropod taxa closest to the origin of birds, and ecomorphological
interpretations of these characters, leads me to favor a gravity-assisted,
facultatively arboreal ("trees-down") origin of flight in birds.

Plus, the idea of small maniraptorans leaping from trees is pretty darn
cool, IMHO.<<

Yea!
TRACY L. FORD
DINOHUNTER