[Taxacom] Are species real? Doesn't matter

[Ken Kinman]

Dear All,
      Whether species are "real" (however one might defined that term) is 
more important to some workers, less so others.  Given my view that species 
are real but fuzzy, that is not surprising in the least.

      The comparisons with physics are certainly valid if you don't carry 
them too far.  When one pregnant female (or a small group of individuals) of 
a species colonize an island, it is much like a neutron decaying into a 
proton (mother group) and an electron (exgroup).  The mother group is 
admittedly only changed by a neglible amount of mass, but in a biological 
system it is really no more significant than the mere death of the same 
individual or small group of individuals----HOWEVER, biologically it is 
extremely signficant if (and only IF) the exgroup survives, proliferates, 
and evolves into a healthy new population (and when it goes from subspecies 
to species is arbitrary and contingent on reproductive isolation that may be 
slow or may be relative quick).  That's where different workers may 
interpret the fuzziness one way or the other.

      Luckily, extinction usually has wiped away intermediate populations a 
long time ago.  So the American Robin is pretty much universally regarded as 
a distinct species with no closely related populations to cause controversy. 
  Other cases are not nearly so clear cut since evolution has not eliminated 
those fuzzy intermediate populations.  Whether we regard intermediates as 
hybrids between two species or as intergrades between two populations 
(within a species) can cause controversy.  I regard such cases more as a 
question of fuzziness rather than a question of reality.

      At the other extreme of speciation (from the single pregnant female 
colonizing an island), we have a species splitting roughly in two.  
Intermediate populations can be killed off for a variety of reasons, and the 
outlying populations become increasingly isolated reproductively.  This is 
more like a molecule of hydrogen gas (H2) being split into two hydrogen 
atoms.  Then there are other cases that are in between such symmetrical 
splits and the extremely assymmetical splits discussed earlier.   That's 
where a lack of information generates even more controversy.

    In any case, biology is more complicated than physics in that electrons 
don't evolve into protons or neutrons, BUT the biologically equivalent of an 
electron CAN evolve not only into a whole new species that is more populous 
than the mother group, but even occasionally evolve into a whole new family, 
class, order, or even phylum of organism given enough divergence and time.  
Doesn't happen very often, but over long periods of time it does happen now 
and then.
  ---Cheers,
          Ken Kinman

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