Real Species

Curtis Clark jcclark at CSUPOMONA.EDU
Sat Apr 17 10:12:15 CDT 2004

At 01:11 2004-04-14, Richard Pyle wrote:
>Could I impose on you to make the case for me that species are "real"?

1. As I mentioned in the post that seems to have started this, the study of
speciation presupposes that it is a real process, with an outcome. Academic
courses in speciation often start with "species concepts" and then go on to
mechanisms, but the last time I taught the subject, I taught mechanisms
first: Let's look at what is happening, and then characterize it.

2. "Species boundary debates" are meaningless if species aren't real. The
fact that people debate about the boundaries of some species, but not of
others, for me reinforces that view.

3. In sexually reproducing eukaryotes, speciation creates phylogeny. Gene
trees are indeed trees, but sex scrambles them into networks. That the data
at broader levels fit a tree model better than a network model has to be
(IMO) the result of lineage splitting, which gets us back to species.

4. Human perception of species is less culturally biased than human
perception of many other things. There has been a lot of ethnobiological
work along these lines, and a lot of disagreement about what it means, but
it's clear to me that people are distinguishing *something*.

So there are units of nature that people distinguish, some (but by no means
all) with fuzzy boundaries. Biologists study the population genetic and
ecological means by which these units form, and the patterns left by their
history. Seems pretty real to me.

Curtis Clark        
Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
Professor, Biological Sciences                   +1 909 869 4062

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