[Taxacom] Reproducibility of descriptive data

Bob Mesibov mesibov at southcom.com.au
Fri Sep 11 06:25:59 CDT 2009


This increasingly poorly-named thread echoes many, many others on Taxacom over the years. You are not likely to persuade many regulars to your position on species boundaries, including me. On the other hand, it doesn't look like the regulars are making much headway in persuading you away from your position, either. Sigh.

I'll just make a couple of small points and then shut up.

First, the Linnean system doesn't rely on just one particular choice from among the dozens of species concepts, and it doesn't wither up and blow away when one species-concept fashion changes to another in biology. As you have so clearly pointed out, a Linnean species name is tied to a type specimen and is a taxonomic convenience. It isn't meant to imply something universal about how things reproduce and how living things vary. Please don't argue that it should.

Second, you wrote: "if reproductive isolation wasn't the norm, then we simply wouldn't find organisms falling as they do into identifiable morphotypes". Can I point out that this is the contrapositive of your argument that identifiable morphotypes only arise through reproductive isolation? [IF identifiable morphotypes, THEN reproductive isolation occurred; IF NO reproductive isolation, THEN NO identifiable morphotypes].

A lot of us Taxacomers don't accept the argument, except in the trivial sense that geographical isolation and ecological isolation *may* lead morphologically distinct populations to fail the Mayr BSC test. There are also a lot of single, identifiable morphotypes in this world which are truly reproductively isolated. Among sexual forms, they're generally called cryptic species.

Dr Robert Mesibov
Honorary Research Associate
Queen Victoria Museum and Art Gallery, and
School of Zoology, University of Tasmania
Home contact: PO Box 101, Penguin, Tasmania, Australia 7316
(03) 64371195; 61 3 64371195
Website: http://www.qvmag.tas.gov.au/mesibov.html

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