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Re: Ruben Strikes Back
In a message dated 9/24/99 1:37:59 PM EST, eamalitz@hotmail.com writes:
<< An interesting hypothesis- has it ever been published before? It is
obviously not favored by most paleontologists. >>
Well, I published a popular-science version of the present version of BCF
("birds came first") in the June 1994 OMNI--rather in the "lunatic fringe"
but published just the same. Also noted it in Mesozoic Meanderings #2 first
and second printings, 1991 and 1992. But I'm still working on the fullest
version, for the third edition of MM.
One problem with the ground-up hypothesis--aside from the vast physics
difficulties--is that the theropod lineages leading up to flying birds each
repeatedly lost flight adaptations and re-evolved the same kinds of
adaptations for cursoriality and terrestriality convergently (e.g., small
forelimbs, vestigial sternum, reduced hallux), and these convergences are
misleading the cladistic analyses. At very least, this possibility has not
been fully addressed in any cladistic analysis I know of.
As I've mentioned before, the ground-up hypothesis requires us to accept a
miracle, namely, that an array of features each of which evolved
independently as an adaptation for cursoriality, terrestriality, or predation
suddenly gave us an animal fully adapted for flying. This is the part that
the ornithologists simply don't buy, and why they will not accept dinosaurs
as bird ancestors despite overwhelming cladistic evidence that this is the
case. All that needs to be done is to decouple the ground-up hypothesis from
the cladistic analyses--the cladistics does >not< show that flight evolved
ground-up, because it says nothing about the lifestyle of the common
ancestors at the nodes along the lineage leading toward birds. These common
ancestors could well have been much more birdlike and much less dinosaurlike
than we have imagined; the cladistic analyses would remain the same.