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Re: attack on dinosaur--horrific video
I remember it was thought not too long ago that end K dinosaurs were the
largest of their particular clades (e.g., _T. rex_). Your data doesn't
Well... the dataset I had, analyzed with the rather primitive method I used,
said there was a trend to increased size, but only in the Late Cretaceous,
and not for all clades (for example, I did not find any trend whatsoever in
sauropods or even sauropodomorphs as a whole). Said method cannot
distinguish between the effects of time and phylogenetic inertia, so chances
are good I'll find even fewer trends next time.
And then, of course, I can't imagine the size difference between
*Daspletosaurus* and *Tyrannosaurus* can be explained by selection for nest
Due to an amazing system of connective tissue supports, a fetus has
virtually no impact on a mother's ability to run away--except at the very
end, of course.
Amazing...the mother coughs up the joey?
What is that muscle?
No idea what, if anything, it's homologous to. It's a muscle in the pouch.
Truly an amazing aspect of marsupial reproduction. But the whole
point--teleologically-speaking--of placental reproduction is
investment--that a few gifted offspring are better able to move more genes
into more future offspring than r strategist, albeit r strategists flood
the reproductive scene with many disposable units.
Sometimes. Sometimes not! This is why both K- and r-strategists still exist.
It's also why there's a wide variety of strategies within placentals and
within marsupials (in the former, compare mice and men; in the latter, the
koala and the Tasmanian devil).
In a stable environment, K-strategists have an advantage. r-strategists, on
the other hand, have an advantage in unstable environments -- as well as in
environments that have suddenly become unstable (mass extinction events).