Are species real?
kmagnacca at WESLEYAN.EDU
Tue Apr 11 13:54:36 CDT 2006
Rich Pyle wrote:
> The point is this: When you draw an arbitrary line through time (say,
> 2006, or the 20th ceuntury, or the Holocene), that line will intersect
> some assembalges that seem unambiguously delineated from all other
> assemblages (e.g., Homo sapiens), and some assemblages for which there is
> a great deal of ambiguity about where species lines should be drawn.
> Perhaps the frequency of the former is vastly greater than the frequency
> of the latter, in which case the latter can be written off as a minor
> "edge effect", a narrow "fuzzy" halo around a small number of cases in a
> context otherwise dominated by objectively discernable species. However,
> from my perspective, in many groups it seems that abiguity is the norm.
The thing is, you're conflating the realness of species with our ability
to discern them. Lumping and splitting usually come down to whether you
think the morphological or other differences between individuals are
significant enough that they are separate species, because we have no real
way of knowing if or how often they interbreed. I think the cases where
the organisms in questions are really ambiguous *as species* - i.e., are
in the process of splitting into two species - is much lower than the
number where we simply don't know enough about them and have to make
decisions by squinting our eyes and drawing a line. As an aside, this is
also the reason why plants species are perceived as being less "good" than
animals, because there tends to be much more morphological variation,
which makes this method less accurate and allows for greater controversy.
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