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Re: PNAS



"On the other hand, it would have been quite possible for birds to have evolved 
and then, at some point, have various species lose their flight capabilities 
and become ground-dwelling, flightless animals - the raptors. This may be 
hugely upsetting to a lot of people, but it makes perfect sense."

I have no problem with the "Dromeosaurs" (why must they use "raptors" from 
Jurassic park, Raptors are most certainly flighted) being secondarily 
flight/glideless.
If you call a gliding/flying feathered animal a bird, then sure, Dromeosaurs 
are flightless/glideless (except for the ones, such as Microraptor, that did 
glide) birds.
This doesn't mean these "birds" that evolved and gave rise to the likes of 
velociraptor, didn't do so from theropods (and thus were still theropods).



--- On Tue, 2/9/10, Tim Williams <tijawi@yahoo.com> wrote:

> From: Tim Williams <tijawi@yahoo.com>
> Subject: Re: PNAS
> To: dinosaur@usc.edu
> Cc: tijawi@yahoo.com
> Date: Tuesday, February 9, 2010, 7:53 PM
> 
> > From the article, it looks their beef is with the
> > "ground-dwelling"
> > parting, not so much the "theropod dinosaurs" part.
> 
> 
> No, the "theropod dinosaurs" part gets dumped on too:
> 
> 
> "...the newest PNAS research, Ruben said, are actually much
> more consistent with a different premise - that birds may
> have had an ancient common ancestor with dinosaurs, but they
> evolved separately on their own path..."
> 
> 
> And I love this quote (from the article):
> 
> 
> "This model was not consistent with successful flight from
> the ground up, and that makes it pretty difficult to make a
> case for a ground-dwelling theropod dinosaur to have
> developed wings and flown away," Ruben said. 
> 
> 
> For some reason (as decreed by Ruben &c) evolution of
> flight must be either "ground-up" or "trees-down"; it could
> not incorporate both behaviors.  I've never believed in
> this "ground-up"-versus-"trees-down" dichotomy.  Why
> not?  Because it's bullsh*t.
> 
> 
> Many birds spend time on the ground, and spend time in
> trees as we
 ecology is quite
> common among extant bird species.  But for reasons that
> make no sense at all, some people (see above) claim that
> such an ecology is strictly prohibited for non-avian
> theropods.  They were either tree-dwelling gliders, or
> ground-dwelling cursors, but never both.  Like I said:
> Bullsh*t. 
> 
> 
> And on it goes...
> 
> 
> "On the other hand, it would have been quite possible for
> birds to have evolved and then, at some point, have various
> species lose their flight capabilities and become
> ground-dwelling, flightless animals - the raptors. This may
> be hugely upsetting to a lot of people, but it makes perfect
> sense."
> 
> 
> Oooohhh... as toey as a Roman sandal.
> 
> 
> Cheers
> 
> Tim 
> 
> 
> 
> 
> Send instant messages to your online friends http://au.messenger.yahoo.com 
>