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Re: Tiktaalik
I'm talking body plans.
Yeah -- what, if anything, is a body plan.
No matter how awe-inspiring a lungfish's
cakehole is, it's not going to help it move around on land.
No matter how awe-inspiring a tetrapod's hand or foot is, it's not going to
help it eat anything even as hard as a cornflake. Look at the Paleozoic
diversification of lungfishes...
Oh no! Not those horrible "ranks"! I'm not talking typology here (heaven
forfend!), but transformations involving locomotion in (or on) two
different
kinds of media.
In this respect *Tiktaalik* is no more spectacular than your average
frogfish.
Tetrapods (including ourselves) are still just uppity
lobe-finned fish, and birds will always be theropods. But both
transitions
involved major transformations, associated with water-to-land and
land-to-air.
I keep hearing "major". :-)
Not convinced? Ask yourself this: Why did _Nature_ magazine dedicate a
combined 18 pages to the discovery of _Tiktaalik_? It made the cover too.
It was not just because this critter was "photogenic" (though it was that
too).
Because our own ancestry is involved (hey, I'm not interested in lungfish
either), because more people are interested in the transition to land (which
was far away from *Tiktaalik* -- try *Pederpes* at best) than the transition
to durophagy -- which again may just be because we're not lungfish --, and
because, as I wrote, "the changes are photogenic": an extremity with fin
rays and a wrist joint is new to science.