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RE: Do we have dromaeosaurid evolution backward?
> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu]
> On Behalf Of Matthew Martyniuk
> Sent: Thursday, August 25, 2011 8:41 AM
> To: DML
> Subject: Re: Do we have dromaeosaurid evolution backward?
> I may misunderstand the principles behind WAIR, but a lot of
> arguments I've read here and elsewhere in support of it as a
> precursor to flight strike me as circular. In all the
> literature and videos I've seen concerning how WAIR works, a
> complete upstroke appears to be necessary.
Right here is the misunderstanding.
WAIR is possible with anteroposterior flapping (modern birds do this, and
kinematically possible by non-ornithothoracine
maniraptorans), whereas flapping flight requires dorsoventral flapping. Thus,
you can do WAIR without a full "above the shoulder"
excursion of the humerus.
(You--well, birds--can *also* WAIR using the full dorsoventral flap.)
Also, WAIR has the advantage as a selective regime for the origin of flight
because it can work incremental: it isn't all "all or
nothing" situation, but rather any slight change in feather size, power to the
forelimbs, etc. directly benefits to the angle of
ascent possible. That is to say, a non-ornithothoracine need not be as good at
WAIR as any living bird but still get a selective
advantage in its use. AND that advantage literally puts it in a situation were
selective pressures for other uses of pennate
feathers and aerial locomotion are possible.
A good review of WAIR studies can be found in
And don't forget to check out the literature on Controlled Flapping Descent
(CFD), the oft-neglected downward "trees down"
counterpart to WAIR
http://dbs.umt.edu/flightlab/ is your one-stop non-shopping (i.e., free) site
for all your WAIR-related publications and videos...
(No, I'm not getting kick backs from Ken Dial to post this...)
Thomas R. Holtz, Jr.
Email: firstname.lastname@example.org Phone: 301-405-4084
Office: Centreville 1216
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Faculty Director, Science & Global Change Program, College Park Scholars
Mailing Address: Thomas R. Holtz, Jr.
Department of Geology
Building 237, Room 1117
University of Maryland
College Park, MD 20742 USA