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Re: semilunate carpal



In a message dated 8/6/01 3:09:36 PM EST, twilliams_alpha@hotmail.com writes:

<< Like George's BCF, I think this is putting the cart before the horse.  The 
flight stroke developed from the predatory stroke, not the other way round. >>

I once watched a mourning dove protect her nestlings by slamming a voracious 
California jay with her wings: She was using the flight stroke as a defensive 
weapon. Give her more primitive archaeopteryx-wings with claws instead of the 
wings she now has and a few million years of evolution, and she could easily 
give rise to a lineage of velociraptor-like animals with predatory-stroke 
killer arms.

There's no way that a Velociraptor's arms would have been any good for 
flying. How could you possibly think that they were a step >toward< flight in 
such an obviously non-volant animal (particularly since there were 
contemporary flying birds)? The trouble with evolution is that the characters 
and features that we see in the fossil record don't come with little signs 
attached to them saying things like, "I am evolving into a wing," or "I am 
evolving from a wing." You have to look at the Big Picture of dinosaur 
evolution and see what turns up. It is extremely unlikely that the avian wing 
evolved as a random collection of features that at some point in time all 
miraculously came together into a unified structure perfectly adapted to 
flight--like being dealt a royal flush as your first poker hand--without 
already having some kind of flying function. The Big Picture of dinosaur 
evolution--the one that makes the most sense to me, anyway--is that birds 
evolved by incremental improvements from small arboreal diapsids, and on the 
way scads of archosaur and dinosaur lineages and groups branched off this 
evolutionary line, forever forsaking arboreality to become larger, heavier, 
and more cursorial animals. The common ancestor of velociraptor and modern 
birds was likely a small, archaeopteryx-like flying dinosaur with a strong 
wing stroke that became exapted into the velociraptor's predatory stroke.