emergence of subspecies

[John Grehan]

Martin Bailey wrote

>Darwin, on the other
>hand, (excuse the simplifications) pointed out that any particular organism'
>s ability to survive depended on fortuitous variations in its offspring.
>Changes that allowed the organism to deal with changes in its environment as
>they arose.
>
>So the study of the emergence of sub-species in butterflies makes perfect
>sense.  The challenge is to tie these studies to environmental change if you
>want the rest of the world to listen to you.

Perhaps it will not be necessary to tie studies on the emergence of 
sub-species to environmental change. Many species differences appear to be 
trivial (the difference between one or two hairs for example) with respect 
to environment. Although in the popular press all one hears about is 
natural selection as the primary agent of evolutionary change, genetic 
theory includes concepts of jumping genes that will spread throughout all 
of a sexually reproducing population over generations by jumping, 
reinserting, and gene conversion so a particular element can make more and 
more copies of itself. DNA mechanisms such as unequal crossing-over, DNA 
slippage and gene conversion can lead to internally driven spread of 
elements through a population of individuals. So long as these 'internally' 
driven molecular changes are not detrimental to the requirements of 
survival there will be no necessary correlation with the environment in 
terms of reproductive success of that population - and yet a population may 
evolve and differentiate to become an evolutionary distinct lineage as a 
result.

John Grehan




 
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