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BIRDS CAME ... WHEN?!?!?
BIRDS CAME.... WHEN?!?!?
I'm sure that some of you who've been around here longer than I
(about a year now) have been all through this, but I haven't been
and I'm really curious to hear about this.
Recently, I Emailed George O (DinoGeorge) and asked him to explain
this BCF thing that everyone mentions abstractly. (e.g., "oh lord,
George is on that BCF thing again...") I was fascinated by the
article he sent me explaining it.
For those who don't (as I did not) realize it, George has proposed
a third theory to the traditional choices of "birds are dinosaur
descendants" and "birds are dinosaur second cousins".
Under George's "Birds Came First" theory, the family tree of
theropods is not a main trunk of dinosaurs with branches leading
away and into birds, but instead there is an almost unseen (since
the little critters do not fossilize well) "trunk" of the theropod
tree composed entirely of birds with offshoots going into
gigantic ground-dwelling carnivours bird types.
To take just an example, and I'm trying to be brief.
We all know that there were these Megalosaurus things that were
the top predators of their day. Then they were all replaced by
the Carnosaurs (Allosaurs). Then THEY were all replaced by the
Mega-Coelurosaurs (Tyrannosaurs). Traditional theory is that these
three families (Megalosaur, Allosaur, Tyrannosaur) are branches of
a main trunk composed of dinosaurs. George proposes that, instead,
these are three different branches of the birds who each, in
turn, came down out of the trees, got big, and went into the predator
business. George's theory explains why the dinosaurs that are closest
to birds come along well after the time (Archy) when birds had
already split off from dinosaurs. [There is a LOT more to this,
but I promised to be brief.]
Under BCF, Tyrannosaurus is a descendant of Archaeopteryx.
I've heard people dismiss BCF (and George) in much the same way that
they dismiss creationism, aliens, and man-tracks. "We've been all
through that before you got here, Steve. Doesn't hold water. Just
forget about it and move on."
I don't want a full six-week debate on BCF, but I would appreciate
it if someone would provide (to me or to the list) the officially
refutation (not just dismissal) of BCF.