Re: Paedomorphosis ( Re: BARYONYX' CLAWS )

["Matthew Troutman" <m_troutman@hotmail.com>]

<<I can quite easily imagine all kinds of flying with characteristics 
transitional between completely unpowered gliding and fully powered 
flapping. Whether or not, and which of, these forms of flying actually 
appeared in the lineage that led to modern birds are the big questions. 
But I have great difficulty imagining flapping flight as 
suddenly--miraculously--appearing in a lineage without having been 
preceded by some kind of more primitive, non- flapping flight. The 
muscles required for flapping flight, and the shapes of the bones that 
these muscles move, are required >exclusively< for avian flapping 
flight; they cannot have been exapted from some non-flying use, such 
as--"reverse weightlifting"? (Or what??) This is demonstrated by the 
dramatic reduction of these very muscles in the secondarily flightless 
descendants of more modern flapping fliers. The muscles, and the 
characteristic shapes of the pectoral bones of avian flapping fliers, 
>must< have developed >along with< flapping flight from a kind of flying 
that was not flapping flight.>>

     They muscles and bone structure could have also evloved for 
climbing. Hoatzin chicks can climb quite well with their muscle and bone 
structure. Flight is just not possible without the muscature and the 
bone structure. Humans have long arms, but we cannot just strap on wings 
and fly. Improvements must be made for flight to evolve.

<<Correct me if I'm wrong, but bats seem to make out just fine as fliers 
without those massive avian chest muscles. How do they accomplish this 
amazing feat, if as you maintain, animals cannot fly without "some of 
the flight characteristics seen in birds"? About the only thing bats 
share with birds isthe presence of wings.>>

     Bats have muscles that reach down their entire belly and have 
capacity for increased oxygen intake. Bats have very strong muscles and 
they need bracing like birds do ( their clavicles act like the 
strut-like coracoid ). 

MattTroutman

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