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Re: Still not a happy camper
In fact, the Compsognathus speed estimate is just the most obvious part
of an overall trend (found by Sellers and Manning) that seems to be
clearly erroneous. Namely, they found a near-linear inverse
relationship between body mass and speed. Having gone over the methods
fairly quickly thus far, I have yet to find where this result is likely
to have come from. Regardless, it seems to me that some parameter fed
to the evolutionary algorithm resulted in the model "expecting" mass to
predict speed in a linear fashion (which is dubious to start with), and
in an inverse manner (which is even worse). Obviously, the smallest
animals do not have the highest absolute speeds, so something is awry.
We might expect the smallest theropods to have the highest relative
speeds of the group, and I wonder if there was a glitch somewhere that
ended up translating high relative speed into exceptional absolute
Michael Habib, M.S.
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280 0181
On Thursday, August 23, 2007, at 07:26 PM, GSP1954@aol.com wrote:
The Sellers and Manning paper makes it clear that the modeling of
locomotion still has a long way to go before it produces reliable
Hutchinson told a reporter, the claim in S&M that Compsognathus was
is clearly errant. It is not possible for animals much smaller than
and pronghorn to run at very high speeds because they lack
legs to achieve the very long strides needed to move as very high
there is no way a kangaroo rat for example, much less a cockroac, can
run 35 mph.
With its big tail trailing behind and modest length legs little Compy
probably little or no faster than a chicken.