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Re: Pick one - massive or agile



Inertia has nothing to do with reaction times.
It can explain slow movement speeds, but not response delays

> It takes an elephant much longer to notice a fly 



--- On Mon, 7/5/10, Heinrich Mallison <heinrich.mallison@googlemail.com> wrote:

> From: Heinrich Mallison <heinrich.mallison@googlemail.com>
> Subject: Re: Pick one - massive or agile
> To: dinosaur@usc.edu
> Date: Monday, July 5, 2010, 11:22 PM
> Bah, nonsense! The travel time
> increase for nervous signals is utterly
> irrelevant compared to the increase in inertia. That's
> what's slowing
> huge animals down!
> 
> Heinrich
> 
> On Tue, Jul 6, 2010 at 4:54 AM, Richard W. Travsky <rtravsky@uwyo.edu>
> wrote:
> >
> > http://www.nytimes.com/2010/07/06/science/06obelephan.html
> >
> > It takes an elephant much longer to notice a fly and
> flick it away than it
> > takes a shrew, and the reason is not that the
> elephants great brain is too
> > busy with philosophy, or that it simply does not
> concern itself with flies.
> >
> > Its a matter of round-trip travel time - in the
> nervous system. The trip
> > from the elephants skin to the brain and back again to
> the muscles to flick
> > the tail is 100 times as long as the same trip in a
> shrew, according to a
> > new study published in the Proceedings of the Royal
> Society B.
> >
> > The nervous system acts like an information
> superhighway, sending messages
> > back and forth from the brain throughout the body. The
> bigger the animal,
> > the greater the distance traveled.
> >
> > Nerves have a maximum speed limit of about 180 feet
> per second, said Maxwell
> > Donelan, the studys lead author.
> >
> > It makes sense that in a large animal, like an
> elephant, messages have a
> > longer way to travel, he said.
> > ...
> >
> >
> > http://rspb.royalsocietypublishing.org/content/early/2010/06/24/rspb.2010.0898.full
> > ...
> > As a consequence, larger animals are burdened with
> relatively long
> > physiological delays, which may have broad
> implications for their behaviour,
> > ecology and evolution, including constraining agility
> and requiring
> > prediction to help control movements. ...
> > Large animals may cope with these relatively long
> delays by simply moving
> > slowly, explaining at least in part the low maximum
> speeds of large mammals
> > (Garland 1983; Hutchinson et al. 2006) and providing
> further evidence for
> > the idea that dinosaurs could not be both massive and
> agile (Hutchinson &
> > Garcia 2002).
> > ...
> >
>