Subject: [Tweeters] Gene's query about gulls
Date: Feb 22 16:07:48 2009
From: Hal Opperman - hal at catharus.net


Right on, Gene and Dennis! If you reread my posting you will see that
I put forward only one opinion, namely, that the beauty (and the
truth, and the good, too, if you will) of science is that it
constantly revises its "certainties." That is what has gone on with
the revisions of the previously accepted treatment of the gulls that
you guys are so steamed about, and it is also precisely what is going
on again with your questioning of the rightness of that conclusion.
How could it be otherwise, since both of you are scientists, and good
ones at that? So, marshall your evidence, write it up, submit it to a
jury of your peers, and may science march ever forward! In the
meantime, though, you might reconsider whether you should be setting
up straw men to attack. (Were those shoes I sensed whizzing past my
ears?)

Other than that one statement of opinion, the rest of my posting was
purely informational -- namely, a response to Gene's question about
the sources of the recent changes of the checklist sequence of species
within a subset of the scolopacids and the larids, to which I supplied
chapter and verse. Any interested parties can look these papers up,
read them, and come to grips with their findings.

The AOU's decision to re-split the Baltimore and Bullock's orioles was
based on a comparison of many factors, including genetic evidence
(allele frequencies), leading the authors to observe that "We know of
no other case where there are so many discrete, abrupt, concordant
differences between populations treated as one species." (Burt L.
Monroe, Jr., et al. 1995. Fortieth supplement to the American
Ornithologists' Union Check-List of North American Birds. Auk
112:819-830.) The research that demonstrated the phylogenetic distance
between these two orioles was also published in 1995 (Scott Freeman
and Robert M. Zink. 1995. A phylogenetic study of the blackbirds based
on variation in mitochondrial DNA restriction sites. Systematic
Biology 44:409-420). The authors of this paper, and the AOU Check-list
Committee, came to their conclusions simultaneously and independently,
without reference to one another's positions.

If we really want to have a serious discussion of the intricacies of
determining, and visually expressing, evolutionary relationships, then
we might do well to start with the profound disagreement that exists
between proponents of the biological species concept and proponents of
the phylogenetic species concept. Maybe not on Tweeters, though. Much
worse than shoes would soon be flying, and this is a family list.

And now I think I'll go have a look at the second edition of the AOU
check-list (1895), or any older field guide for that matter.
Everything changes, all the time ? common names, scientific names,
orders, families, sequences. There's no absolute right or absolute
wrong in this process. If there were, science could not function. And
we have seen over and over in human history where absolute certainty
leads us.

Hal Opperman
Medina, Washington
hal at catharus.net










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