[Taxacom] The reality of species boundaries----blah, blah, blah.

Stephen Thorpe s.thorpe at auckland.ac.nz
Tue Sep 15 23:05:07 CDT 2009

Hi Ken,

Hoping that my extraneous (and lengthy) end is sufficiently trimmed for your taste!

>I think the overall conclusion is that species boundaries are both fuzzy and controversial (no big surprise), but more importantly that
their fuzzy boundaries are evidenced by different sets of characteristics in various taxa.  Even among metazoans, differences in
genitalia is going to be important for some groups and  totally irrelevant in others.  Same goes for the relative importance of gene
sequences vs. expressed morphologies.  It really varies greatly  from group to group.
      Basically I am saying that two people can endlessly argue about genitalia or gene sequences until the cows come home, and neither might
be right or wrong when it comes to any particular taxon.  Two people can argue with experiences with two very different sets of organisms and
come to COMPLETELY different conclusions on what is more important. I say "viva la difference", and who knows what might be most important for
any particular eukaryotes.  Prokaryotes are a whole different ballgame (where genetics very often tends to be a greater factor).

There is a big difference, of course, between the undoubted fuzziness and endless/pointless debate about particular species boundaries on the one hand, and debate about the correct species concept in general (e.g. BSC or not BSC). Only the BSC is flexible enough to handle all the problem cases for sexually reproducing organisms, I suggest. The fact that it doesn't necessarily give you a single, precise boundary for some species is in fact a strength of BSC! It can allow for the fuzziness of species boundaries that we sometimes do find in nature.

So, my problem is not with fuzziness of species boundaries, but with those people who seem to think that this refutes the BSC!



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