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Re: Inquiring Minds

Tim Madden <TMADDEN@medicode.mhs.compuserve.com> wrote: 

>Bakker does have some good questions. Why do the number of fossils
>taper off as you get near the time of impact? Shouldn't a graph of
>the fossils show a spike near the estimated time of impact? Why didn't
>ALL species die out?

  If the impact and extinctions are related you wouldn't *necessarily* have
to have a "corpse-count" spike at the iridium boundary.  The reason that a
"spike" isn't required in the scenario has to do with statistics:
preservation statistics, population statistics, sampling statistics, etc.
For a good summary of the whole debate, look at a short paper by
Mike Williams in the Journal of Paleontology, v. 68, no.2, year 1994.  He
does a good job of re-hashing and summarizing all of the extinction
expert's research up to 1994.   
 (really funky drawings, too!)       :-)