Jim Hoffman kindly sent me the abstract of the fossils article that so
impressed me that I erased it.
Here it is:
Proc. Natl. Acad. Sci. USA, Vol. 98, Issue 11, 6261-6266, May 22, 2001
Effects of sampling standardization on estimates of Phanerozoic marine
diversification
Contributed by D. M. Raup, March 26, 2001
Global diversity curves reflect more than just the number of taxa that
have existed through time: they also mirror variation in the nature of
the fossil record and the way the record is reported. These sampling
effects are best quantified by assembling and analyzing large
numbers of locality-specific biotic inventories. Here, we introduce a new
database of this kind for the Phanerozoic fossil record of marine
invertebrates. We apply four substantially distinct analytical methods
that estimate taxonomic diversity by quantifying and correcting for
variation through time in the number and nature of inventories. Variation
introduced by the use of two dramatically different counting protocols
also is explored. We present sampling-standardized diversity estimates
for two long intervals that sum to 300 Myr (Middle
Ordovician-Carboniferous; Late Jurassic-Paleogene). Our new curves differ
considerably from traditional, synoptic curves. For example, some of them
imply unexpectedly low late Cretaceous and early Tertiary diversity
levels. However, such factors as the current emphasis in
the database on North America and Europe still obscure our view of the
global history of marine biodiversity. These limitations will be
addressed as the database and methods are refined.
The article itself had rather more discussion of what the abstract
mentions as "differ considerably."
Burgy (John Burgeson)
www.burgy.50megs.com
This archive was generated by hypermail 2b29 : Sat May 26 2001 - 18:32:17 EDT