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Re: Back-evolution of limbs.
---Jeff Hecht <firstname.lastname@example.org> wrote:
> What I was trying to say -- but didn't say very clearly -- was that
> amniotes had descended from lobe-fin fish, which originally evolved
> limbs as fins. When they came on land, they evolved legs. When some of
> their descendants returned to the sea, their adapted their legs back
> flippers -- essentially fins. -- Jeff Hecht
I guess this isn't computing with me because I've been following this
secondarily-flightless discussion using my newly-acquired, and perhaps
incorrectly-employed, knowledge of cladism.
Aren't we discussing a monophyletic group here, or, more precisely,
whether this group ("dinosaurs" + "birds") is monophyletic or not? It
seemed to me that an analysis encompassing the entire phylum is more a
discussion of ancestral rather than derived characters. If I'm wrong,
could someone please explain why? Thanks.
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