chloroplast and other genes (was Lucy in Newsweek)

Curtis Clark jcclark at CSUPOMONA.EDU
Sat Apr 3 11:10:27 CST 2004


At 02:17 2004-04-03, Richard Pyle wrote:
>On a final note, we often like to think of "species" as being discrete
>entities; but of course they are not.  And because they are not (i.e.,
>because they are "fuzzy"), they do not have a discrete phylogeny.

I was with you until this point, but now I have to object strenuously.
There are no "discrete phylogenies". Phylogeny is our interpretation of a
historical pattern, and in the case of sexually reproducing eukaryotes,
*that pattern is the result of species*. The phylogeny that morphological
cladists look at is the species tree, and that tree is the *consequence* of
speciation, at least in the sense that speciation means lineage-splitting
(which to me is its most useful definition).

Despite the fact that many of us talk about "the true phylogeny", what we
are really after is the ability to make consistent and reproducible
inferences about specific aspects of history.


--
Curtis Clark                  http://www.csupomona.edu/~jcclark/
Web Coordinator, Cal Poly Pomona                 +1 909 979 6371
Professor, Biological Sciences                   +1 909 869 4062




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