Re: What is a Dinosaur? and semilunate carpal

[Dinogeorge@aol.com]

In a message dated 9/6/01 3:08:45 PM EST, david.marjanovic@gmx.at writes:

<< In BCF birds (sensu BCF) begin to fly, then evolve stable wrists, and in 
the
 meantime they have flown by magic? Or by means of _enormous_ muscles on
 their forearms? >>

No, they didn't fly very well at first. They just fluttered to break their 
falls. When their hands/wings began to stabilize, they flew better. Why fly 
at all? It helps to solve the Falling Problem for arboreal animals. It 
doesn't solve >any< problem for cursorial, ground-dwelling predators; 
ground-dwellers have no need to fly, consequently flight adaptations are not 
useful to them and are not usually selected for in their evolution. 
Consequently ground-dwelling animals are extremely unlikely to be directly 
ancestral to flying animals outside the arboreal paradigm. If the evolution 
of flight from ground-dwelling animals is so plausible, why don't pigs and 
kangaroos and people have wings?