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Re: Do we have dromaeosaurid evolution backward?



On Aug 25, 2011, at 10:41 PM, Tim Williams wrote:

> Although the "proto-wings" of bird ancestors might well have been
> quite similar to the incipient wings of modern bird chicks that use
> wing-assisted-incline-running (WAIR), the wing movements required for
> WAIR are actually quite sophisticated.  There are doubts over whether
> the primordial flight apparatus of bird ancestors was up to the task
> of performing WAIR.  Whereas the feathers of basal paravians are quite
> advanced by avian standards, the skeletal (and by inference, muscular)
> adaptations of these basal paravians were comparatively poorly
> developed.


Precisely.  It is particularly the upstroke phase that is in question in this 
regard.  The upstroke phase has received considerably less attention in the 
paleontological and flight evolution literature than downstroke mechanics.  I 
suspect this comes from a fundamental interest in power generation combined 
with a lack of consideration of how vorticity is generated and ended on 
flapping wings.

Cheers,

--Mike


Michael Habib
Assistant Professor of Biology
Chatham University
Woodland Road, Pittsburgh PA  15232
Buhl Hall, Room 226A
mhabib@chatham.edu
(443) 280-0181


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