Phylocode, Cladistics and Eclecticism ...

[Ken Kinman]

Tom,
     I'm talking about *real* apomorphies, the ones that cause the
divergence (speciation) to occur.  At least one such apomorphy must cause a
severe reduction in the ability to interbreed with members of the mother
population.  Any daughter population which lacks such an isolating apomorphy
is still able to interbreed with the mother population, so they are still
the same species.  I'm not arbitrarily stating it to be true, that's just
the way it is.  The ability of populations to interbreed is plesiomorphic.
Interbreeding can continue until a daughter population evolves a
reproductively isolating apomorphy, thus budding off as a new species.
     For example a change in the chemical structure in a pheromone.  This is
caused by a mutation which only gradually spreads in a population.  The
budding population with this new character will always start out small.
That's how evolution works.
          ----TGIF,  Ken



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