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Re: A long post about DUMB METATHERIANS vs EVIL, SMART PLACENTALS



> > << This is hardly a _pattern_.  Merely an observation.  And a scientists
job
> >  is to discover patterns in apparent randomness. >>

And to discover true randomness when it does occur. As HP George Olshevsky
wrote --

> > Even when it's likely that no particular pattern exists? Randomness is a
fact
> > of life.

> But there _is_ a pattern.  Just that it isn't explained by the effects of
> a bolide.  No placentals extinct/most marsupials extinct.

Wrong. Firstly, be aware that you are talking of western North America
alone. Secondly, many eutherians did die out there at the K-T, just
relatively less than metatherians. Thirdly, quite some metatherians survived
and, as has been pointed out onlist several times, even diversified and
spread to e. g. Europe, and died out no sooner than the Miocene.
(Pediomyidae, a LK metatherian family from western NA, seems to have
survived in SA into the Paleocene, along with the eutherian *Cimolestes*,
based on fragmentary evidence.)

> Random would
> say 50/50.  Does this mean that something about marsupials predisposed
> them to the effects of the bolide?  If they were driven to extinction by
> the bolide, then yes!  But no one can suggest what that thing is.

- Different susceptibility to pyrotoxins. Probably not testable even by
phylogenetic bracketing.
- Different habitats. I'd say that burrowers are more likely to survive
global firestorms and acid rain (that must have killed off lots of bacteria,
BTW, just we don't have a fossil record worth speaking of for bacteria) than
surface dwellers, let alone tree climbers.
- Different food requirements.
- Why not some random? Or lots of it?