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Re: Pollen From Permian/Triassic Extinction Show UV Induced Mutations



John Bois (jbois@umd5.umd.edu) wrote:

<Recent Nature paper notes that smaller (adult) animals are limited by 
predation, whereas larger animals are limited by food
supply--and, there is little predation on their juveniles.  Reasons for this 
are that small adults spend more time in an age range
that is targeted by more predators; juveniles of large animals are just passing 
through that age range.>

  Shouldn't this be limited in the factor of predation? The above would seem to 
make sense in regards to an extinction event on a
population, rather than a global mass extinction of a percentage (however 
small) of a given range of species. Climate changes, or
disease, or other natural disasters or alterations can effect a wider range of 
species, and may selectively favor large species
because of the burden of them escaping would be greater, and probably less 
possible. Smaller species tend to be survivors. Look at
the cockroach. Having a mean adult size of low values to all living species may 
argue that _we_ would be easy targets if a Chixulub-
or Manicougan-size event were to occur in the near future, along with 
elephants, lions, those cute little llamas, and seacows.

  Cheers,

  Jaime A. Headden

  Little steps are often the hardest to take. We are too used to making leaps 
in the face of adversity, that a simple skip is so
hard to do.  We should all learn to walk soft, walk small, see the world around 
us rather than zoom by it.

  "Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)