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← Paper Challenges Ideas About 'Early Bird' Dinosaur

Muetze's Avatar Jump to comment 12 by Muetze

Thanks for the reply. :-)

It has to be called something other than a fish in the same way that evolutionary ancestors to humans are not called humans!

I think there's a difference. If you are just talking about any human ancestors, of course those could be anything, even single-celled organisms. Allow me to clarify my example:

All modern bony fish and tetrapods descend from a creature that lived in the Devonian oceans. As I understand it (and I would ask you again to correct me on any of this), this creature was a fish. It had a spine, fins, a jaw and a proto-swim bladder. It might not have corresponded to a specific species of fish alive today, but looking at it, you would recognise it as a fish as clearly as you would call the common ancestor of humans and orang-utans an ape.

Now, my point is this: It is not helpful to ever consider this creature to not any more be a fish. At some point in time, something like Tiktaalik started to show amphibian features, but why stop calling it a fish — just because it changed some of its part around a bit? Why stop calling the animal a fish that first layed its eggs on land? and so on.

In short: Isn't it a more reasonable way of thinking to call *all* creatures fish that descend from fish (and then create subgroups, of course), instead of arbitrarily dividing vertebrates into those that are still finned/scaley/gilly/watery enough to qualify as a fish and those that aren't?

Aren't we *still* fish?

And does this way of classifying organisms correspond to any methodology in modern biology?

Sat, 10 Oct 2009 20:41:00 UTC | #404729