Re: bauplan convergence

["Rob Gay" <rob_redwing@hotmail.com>]

> From: "Ahmed al-Mahasa Sha'ad"
> Are you serious?? You must know about the 'fuzzy' theropods like
> Sinornithisaurus, Bepaisoaurus, Sinosauropteryx which  show a cobvering of
> hair-like structures. Feathers evolved from this- true feathers I mean like
> you see  in Caudipteryx and birds.

Yes, these theropods have some form of furry proto-feathers. However, these 
animals are coming from the late Jurassic and early Cretaceous, and not from 
the time before Archaeopteryx. Yes, this tells us that these dinosaurs had 
proto-feathers, and further study of these animals points towards a common 
ancestor. So, does this common ancestor have some form of primitive 
feathers/flaps/skin anamolies that could have led to 
feathers/proto-feathers. We know (From Archaeopteryx) that some dinosaurs 
had full-fledged feathers by the middle Jurassic. So, are these late 
Jurassic/Early Cretaceous theropods abrerations, dinosaur lineages that 
never developed flight, or descendants of animals that had once developed 
flight and then lost it in favor of (fill in blank).
So, while these finds are quite fascinating, since they occur *after* the 
origin of avian flight, they only lend a hint at how avian flight developed. 
Until we find a pre-Archeopteryx dinosaur *with* some form of proto 
feathers, this all remains speculation, based on extrapolation.

> Who cares???   Did you read my last messsage>?    It is not compulsary for
> ALL lineages to copy each other!@!!Why did creodonts return to the sea and
> evolve into whales, but why not dogs? They are both terestriall carnivores?

The question isn't why hasn't it evolved in other animals, rather, why did 
it develop in dinosaurs in the first place. I guess it was kind of redundant 
for me to ask that, when that was the subject being discussed in the first 
place.

Peace,
Rob


________________________________________________________________________
Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com