[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: He's Just Not That Into New Papers
Those fossil discoveries suggest that both carnivorous and herbivorous
dinosaurs existed in the Jurassic of Mongolia, as in China.
I'll just leave this uncommented. :-)
Krug, A.Z., Jablonski, D., and Valentine, J.W. 2009. Signature of the
end-Cretaceous mass extinction in the modern biota. Science 323:767-771.
ABSTRACT: The long-term effects of mass extinctions on spatial and
evolutionary dynamics have been poorly studied. Here we show that the
evolutionary consequences of the end-Cretaceous [Cretaceous/Paleogene
(K/Pg)] mass extinction persist in present-day biogeography. The geologic
ages of genera of living marine bivalves show a significant break from a
smooth exponential distribution, corresponding to the K/Pg boundary. The
break reflects a permanent increase in origination rates, intermediate
between the Mesozoic rate and the post-extinction recovery pulse. This
global rate shift is most clearly seen today in tropical bioprovinces and
weakens toward the poles. Coupled with the modern geographic distributions
of taxa originating before and after the K/Pg boundary, this spatial
indicates that tropical origination rates after the K/Pg event have left a
permanent mark on the taxonomic and biogeographic structure of the modern
biota, despite the complex Cenozoic history of marine environments.
This is _really cool_.
_If_, that is, all bivalve workers use the same genus concept (where by
"all" I mean "all except, at most, a statistically negligible minority", and
by "same" I mean "measurably and quantifiably identical at a high
And this I... doubt.
What should have been done would have been to count cladogeneses, not
genera. Of course, that would have required a stupendously huge
time-calibrated supertree, in other words, a PhD thesis of its own.
Paleobiological studies suggest that species diversity is
driven largely by abiotic factors such as climate, landscape,
or food supply,
of which food supply is only an even partially abiotic factor if you're