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Re: A Perspective on Cope's Rule



Jaime,
Just chewing on that food....
I think the bias is not on the collectors part alone but also on the scientists describing the fossils. If I were finding large jaw fragments of rare animals instead of little mammal jaw stuff around my ranch, the world would be beating a path to my door. It is much more gratifying to describe and work with the giants instead of the little guy. The little stuff sits in drawers waiting for a grad student.
Frank Bliss
MS Biostratigraphy
Weston, Wyoming


Remember evolution is the process, not where you find yourself now!


On Jan 6, 2005, at 7:29 PM, Jaime A. Headden wrote:

Based on the differentiation of animals to geography, space, and Cope's
Rule, I figured I'd plop this idea out here for commentary:

Give ourselves an ecology of allosaurs, apatosaurs, othnieliines, and
some tiny mammal, say *Foxraptor.* These animals show a clear size
delineation, and a neccesity of spacial requirements without overlap: an
allosaur cannot occupy the same space as an apatosaur (unless it's
consuming it), for example.


In a given area, large animals take up more space and are thus less
common in concentration than smaller animals: A thousand foxraptor in the
space of an apatosaur.


Cope's Rule predicts that a trend to increase size is present in
biology, and in a lineage, smaller animals will tend to become larger. But
it is possible this is a selection bias. We will tend to find larger
animals because of the access to larger animals than smaller in an area,
given the ecology of Ngorogoro Crater or the exposure at Como Bluff. Thus
we will more easily see larger animals and a replacement over smaller
animals because of the access to smaller animals will be less obvious or
less inherent in fact.


  Hmm ... food for thought?

  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)


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