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 the "standard theory" (judging from this list it consists of
 hundreds of competing hypotheses) there is a function that can be performed
 without stiff wrists but works _better_ with stiff ones, so when stiff
 wrists evolve -- of course by chance, as mutations happen -- they bring a
 selective advantage. >>

That's the kind of tautology that fails to drive the standard theory. "Well, 
stiff hands must have been useful to them, otherwise they wouldn't have 
evolved them." Useful how? They were certainly useful when it came around to 
acquiring wings, but what about when wings were still way off in the future 
of possibilities?

But if they already had a marginally useful wing that would be improved by 
being stiffened, that's a positive selection mechanism that would >drive< the 
evolution of the wing. A vertebrate wing isn't going to evolve by random 
chance; it's too complicated a structure. It's not going to evolve as a set 
of randomly acquired, undirected characters that just happen to assemble 
themselves into a wing, any more than a shattered cup will reassemble itself 
when you throw the pieces back onto the table.