[Taxacom] New book on species
Richard.Zander at mobot.org
Mon Sep 7 21:33:23 CDT 2009
"Fallible beliefs"? Very postmodern, Stephen. Must we really treat science as a wrangle among profit-taking stakeholders, or can we find some genuine point of agreement about discovering new facts and well-supported theories on which to base both action and an advanced science?
Species are real. They are out there. So are genera. Aristotle, I understand, first recognized these nested groups. He didn't need the biological species concept to do so.
The BSC works well with birds, and other fairly well-understood panmictic organisms, so I understand. It fails with many or most other organisms.
What holds species together when populations are distant for thousands of years? I don't see neutral expressed traits generated a phantasmagoria of variation between such isolated populations. Instead there is apprently strong stabilizing selection on expressed traits in spite of abundant genome variation from point mutations at single sites to sub- and neofunctionalization. The New Synthesis was wrong about gradualist evolution (against some element of punctuated equilibrium), in my opinion, but right about little change in expressed traits. I liken this to a Volkswagen modified with a small but powerful Chevy engine but because of the speed laws (the environment) it's still a VW. Bock has pointed out the paragenetic function of the environment as a way for species to hang together, and I extend it to genera, where all species share an "envirosome" that regulates (interacting with the genome's phyletic constraint) the evolution of the genus.
Richard H. Zander
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166 U.S.A.
richard.zander at mobot.org
From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Stephen Thorpe
Sent: Mon 9/7/2009 8:47 PM
To: Kipling (Kip) Will; TAXACOM at mailman.nhm.ku.edu
Subject: Re: [Taxacom] New book on species
If you were to describe two new species, unrelated to anything else, and you believed that together they form a monophyletic group, you could choose to put them as one or two genera, depending on taste! It would be a subjective decision of the kind you describe.
If, however, you had specimens from two populations, and you believed that there were no reproductive barriers in place (only geographical ones), then you would have no choice but to consider them one species, not two! Assuming a biological species concept, anyway!
Another taxonomist might claim to use a morphological species concept instead of a biological one, and say "well I know there is just the tiniest difference in colour, and nothing else, but it is perfectly consistent between populations, so I am going to call them distinct species!". Whether or not use of the term "population" betrays a covert use of the biological species concept, I am not entirely sure! I don't see morphospecies as a sensible option precisely because males and females (and immatures) of a single biological species can be quite distinct morphospecies, so it seems to be somehow impossible to break free of a biological species concept! It seems to be almost true by definition that if you are concerned with "species" (in some general sense = kinds) in biology, then you must use the biological species concept! But as soon as you do, your "opinions" about species in biology become fallible beliefs ...
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