Re: Flight SPECULATION

["Nicholas R. Longrich" <longrich@phoenix.Princeton.EDU>]

On Sun, 3 Dec 1995, Rob Meyerson wrote:
> 
> The problem is that even if we decide what idea makes the most sense, there=
>  will always be the nagging question of what *actually* happened (just=
>  because something doesn't make sense, doesn't mean that nature didn't go=
>  that way; logic has it's limits).  As Rowe pointed out, the only problem=
>  here is with our inability to imagine what went on.  My question: how close=
>  was Archy to the true origin of flight?  This may give us a clue.  If it=
>  turns out that there were no trees in the place where flight evolved, then=
>  any arboreal explanation falls flat.  I suspect that we know so little=
>  about flight evolution that only the most outlandish of theories should be=
>  ignored (look at poor Wegener, for example).  Just a few suggestions to=
>  keep egg off our faces.
        It's not impossible that Archaeopterygians evolved on the 
Solnholfens, but not likely. When should we expect to start finding birds 
in the fossil record? We shouldn't be finding the early forms. We 
shouldn't be finding dead ends that did not ultimately lead to anything. 
We should expect to start finding birds AFTER they become successful, 
start radiating out, and spreading across wide areas and many niches. 
Confuciusornis reinforces this idea, in my opinion. So Archaeopteryx is
 just one of many Archaeopterygians in the Late Jurassic, important only 
because it got fossilized. Why should we assume that just because 
they find an animal in an area that it evolved there? 
        Imagine a future paleontologist. They find a lion in South 
America, a dingo in Australia, a horse in Europe, and a scientist in 
Antarctica. Aha! He concludes. This must be where these animals evolved! 
The problem, of course, is that lions lived over five continents, people 
seven, horses evolved in the New World and spread to the Old, etc. If we 
look at modern birds, gulls may range around the Arctic circle, parrots 
range from Peru to Timbuktu to Queensland to Auckland, etc. etc. Birds 
have HUGE distributions. Even if Archaeopteryx was only a half-assed 
flyer, the distribution for that genus, let alone the family, could have 
been huge. Not that we can't figure anything out- obviously, horses 
evolved in the New World, not the Old, because that's where the youngest 
fossils are. But we just have to be careful, because saying that 
Archaeopteryx evolved in the Solnholfens might be about as accurate as 
saying that those lions and mammoths we find in South America must have 
evolved there. 

        -nick L.