Flight - yet again (was RE: DINOSAURNEWS - Great Asian Dinosaurs, I'd Rather Dig Them Up, Running Gators, Jurassic Coastline, Giant Roach

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Roger Smith wrote:

>**  Taking Wing
>As the idea that birds descended from dinosaurs gained acceptance by all
>but a few paleontologists, so too did the cursorial hypothesis

A nice, succinct summary of Dial's work - but again the article shows the
inaccurate tendency for equating a "ground-up" (gravity-opposing) ecological
origin of bird flight with a theropod-dinosaur phylogenetic origin of birds.
There's actually quite a few gravity-assisted models of avian flight that
propose a theropod dinosaur as the ancestor of birds.

And there's this so-called "explanatory gap": "As far as tree dwellers go,
of the hundreds of nonavian gliding vertebrates around today, not one flaps
its appendages."  

True; but maybe it's flapping that turned pro-avians into powered flyers.
Tracy Ford put it in a nutshell when he suggested that perhaps gliders don't
ever become flyers - they just become better gliders.  Flapping wrecks the
glider's aspect ratio, and most gliders want to stay in the air for as long
as possible.

(And are there really "hundreds" of vertebrate gliders?  Dozens, perhaps -
especially if you remove animals that simply parachute to the ground in a
controlled descent.)

Enough nit-picking.  Have a fun weekend everyone.



Tim