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Re: a little background



On Thu, Feb 28, 2002 at 12:39:07PM -0800, John R Hutchinson sent:
> Now we're caught up.  I hope people understand that this was not some
> project that Mariano and I sketched on a napkin after a few beers last
> week, and decided to publish as an assault on paleontology, and then
> abandon to let paleontologists pick up the pieces.  This was a lot of
> work and we are serious about it, and I will continue pursuing these
> sorts of scientific questions for the rest of my career.  I welcome
> disagreement with our work as long as it is scientific and not
> superficial.  I expect SVP next year will have at least one talk
> criticizing our research, and I'm sorry that I won't be there this
> year (first time in 6 yrs!) to respond.  We'll work things out in the
> scientific peer review process over the next few years, I hope.

I think it's extremely interesting.

(My own suspicion is that the theropod mass models are badly out of
whack; I will cheerfully believe in large theropods with half their body
mass in their legs, and have the suspicion that the apparent general
size limit for that body plan may be at a much lower mass point that
hitherto suspected.)


I'm also thinking that it does something kinda violent to models of
dinosaurian ecology.

We have little zippy dinos -- everyone agrees that, proportionately,
hypsilodonts and ornithomimids, etc. had the ability for a true run --
and we have big, slow dinos; multi-ton carnivores and multi-ton
herbivores.

The multi-ton herbivores ecologically dominate; really inexplicably high
proportions of the ecology.

Why?

The little zippy guys aren't at risk of predation, so long as they can
outrun a predator which can't profitably consume them on an
effort/return basis, and which can't reliably catch them, either.

Which implies that either the juvenile theropods were just as fast, and
keeping the numbers of the little zippy guys down -- which sugguests a
horridly unstable ecology, as per the arctic lemming cycle -- or, well,
what?  The striding giant predators can consume the equally locomotively
constrained giant herbivores, sure, and the herbivores want to be big if
they're already slow, but if so, why are the smaller dinos so rare and
the large ones so common?

-- 
graydon@dsl.ca   |  Hige sceal þe heardra, heorte þe cenre,
                 |  mod sceal þe mare þe ure maegen lytlað.
                 |   -- Beorhtwold, "The Battle of Maldon"