[Taxacom] Semantic Web: What is a species?
kennethkinman at webtv.net
Fri Jan 30 09:23:02 CST 2009
The distinction between tokogenetic and phylogenetic is useful to
a point. However in reality, I believe there is a continuum of
possibilities between strictly tokogenetic and strictly phylogenetic.
When a species is well on its way to dividing into two species,
its overall population structure has shifted considerably toward the
phylogenetic side of the continuum (but it is still just one species).
Therefore, I think it is perfectly reasonable to think of paraphyletic
mother species giving rise to daughter species.
I think it is great that Hennig got us on the road to rigorous
cladistic "analysis". However, when it comes to translating the results
into strictly cladistic classifications and nomenclature, it created a
divisive and confusing mess that only continues to get worse. And its
most extreme manifestation (PhyloCode) hasn't even gone into effect yet.
I'm quite certain that the notions of monophyly, paraphyly, and
polyphyly apply only to higher taxa and not to species. (Monophyletic
group is defined as a group consisting of an ancestral species and all
its descendant species, at least sensu Hennig.) This stems from the
notion that the relationship of individuals within a species is not
strictly hierarchical (tokogenetic as opposed to phylogenetic). This
distinction is useful because it does not muddle classifying higher taxa
with studying the process of speciation, the two being distinct, however
related, research programs.
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