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Re: From Science New, and more
I only meant to say that the study of dinosaurs is appropriate
On Sun, 10 Nov 2002, John Bois wrote:
(for all we know) for the the study of dinosaur's extinction
Right. Note the loss of some diversity about 2 million years before the
end, which suggests another factor causing a preliminary extinction.
--this is true
whether or not some massive force hit. For example, what was it about the
dinosaurs that made them susceptible and not other living things?
You mean many other living things. Dinosaurs were supposedly more
vulnerable because of their prodigous food requirements at a time of energy
depletion. Recent research, however, casts doubt on the impact scenario. The
initial proliferation of ferns while the dust was settling rules out
freezing temperatures and darkness. (N.C. Arens, pers. comm.)Modern analogs
of the K-T fern species, including a tree fern, require full sun to make
spores, which are present in the upper impact layer.
Ordinarily the replacement of angiosperms and conifers with ferns would
probably doom the dinosaurs since ferns aren't energetically rewarding. Tree
ferns requiring full sun may well have been different. In any event recent
research suggests only 10-20% of the biomass burned, which implies
widespread survival of "good" vegetation in the absence of an impact winter.
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