[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: CNN: how first birds flew



In a message dated 5/7/99 5:02:12 PM EST, th81@umail.umd.edu writes:

<< The point of the paper in
 question is to show that, contrary to expectations, a running
 _Archaeopteryx_ or other primitive protobird flapping its wings actually
 adds thrust, and thus becomes faster.  Goofy sounding, but that's what their
 model shows.  Find a flaw in their model, and get your paper published as a
 Correction! >>

I would certainly agree that archy could have taken off, after being 
grounded, by running and simultaneously flapping its eminently flightworthy 
wings. This is how many modern birds take off (e.g., vultures after a heavy 
meal, large storks, etc.) when a standing-start takeoff is difficult or 
impossible. But this mechanism could not possibly have been employed by 
prevolant birds (no amount of running will get, e.g., an ostrich into the 
air). So the paper says very little about the evolution of flightworthy 
wings--but paradoxically it >does< say quite a bit about one reason behind 
the evolution of cursoriality in theropods(!): a higher running speed would 
have enabled a grounded flying dino-bird (for which a standing-start takeoff 
would not have been an option) to become airborne more quickly. Theropods 
(=secondarily flightless dino-birds) would then have dispensed with the 
flying and improved the cursoriality.