[Taxacom] Are species real? Doesn't matter
kinman at hotmail.com
Thu May 31 22:07:22 CDT 2007
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
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