Re: Paedomorphosis ( Re: BARYONYX' CLAWS )

[Dinogeorge <Dinogeorge@aol.com>]

In a message dated 98-04-10 22:53:14 EDT, m_troutman@hotmail.com writes:

<< How can an animal fly without some of the flight characteristics 
 seen in birds? Flight muscles exert strong compressive forces (and need 
 to ) and these forces need to be supressed. I just keep on thinking 
 about the statement that if Daudalus were to be able to fly with his 
 wings his torso would have to be six foot thick with muscle and his 
 complete wingspan would have to be 140 feet! The only type of flight 
 that I can imagine is flapping flight, however primitive it may be. >>

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.

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 is
the presence of wings.