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What is evolution?

L.A. Moran lamoran at gpu.utcs.utoronto.ca
Sun Sep 15 07:54:52 EST 1991

Tom Schneider says,

     "...these so called molecular clocks are only an approximation. 
      Besides, what they measure is the changes which DON'T matter!
      The changes in cytochrome C are equivalent to the rearrangements 
      of water molecules in a glass of water. I wouldn't call that 
      evolution, but in the perverted way people think these days, 
      it is.  (Those who want to defend this idiocy, flame away!)
      The really interesting evolution is harder to capture (eg the
      creation of a whole new gene) so people tend to ignore it!"

It is obvioulsy useful to agree on a definition of evolution if we are going
to argue about it! There is a discussion on this topic under way in 
talk.origins for those of you who want to pursue it. The most popular
definition among evolutionary biologists seems to be something along the 
lines of "evolution is a change in the frequency of alleles in a population".
Here is what Futuyma has to say,

     "Biological evolution ... is change in the properites of populations
      of organisms that transcend the lifetime of a single individual....
      The changes in populations that are considered evolutionary are 
      those that are heritable via the genetic material from one generation 
      to the next. Biological evolution may be slight or substantial;
      it embraces everything from slight changes in the proportion of 
      different alleles within a population (such as those determining
      blood types) to the successive alterations that led from the
      earliets protoorganism to snails, bees, giraffes, and dandelions."

                                              Futuyma, D. J. in
                                              EVOLUTIONARY BIOLOGY
                                              Sinauer Associates 1986

Just like Futuyma I happen to think in a "perverted" manner that the fixation
of different alleles in populations is an example of evolution. Tom may reject
this definition of evolution if he wishes but I think that he is then obliged
to let us know what evolution really is (in his opinion). We can't have a 
serious discussion about evolution unless he tells us what he means.

Tom, why do you believe that fixation of neutral mutations in cytochrome c
is NOT evolution? Do you have another word to describe this process?
What is your personal definition of evolution? 

Please note that in spite of the fact that Tom referred to the standard
definition as "idiocy" and "perverted" I have avoided flaming back....
even though he obvioulsy doesn't know what he is talking about. (-:

Laurence A. Moran (Larry)
Dept. of Biochemistry

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