(no subject)

Richard Jensen rjensen at SAINTMARYS.EDU
Thu Jan 7 13:10:20 CST 1999

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Message-ID: <3694E8FC.FCA99DFB at saintmarys.edu>
Date: Thu, 07 Jan 1999 09:03:56 -0800
From: Richard Jensen <rjensen at saintmarys.edu>
Organization: Saint Mary's College
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To: Doug Yanega <dyanega at MONO.ICB.UFMG.BR>
Subject: Re: "(morpho)" species?
References: <b2b99b0e09021004b705@[]> < at mono.icb.ufmg.br>
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I find the concerns about using morphospecies for biodiversity studies rather
amusing and interesting.  I would like to ask, perhaps a naive question, What
is the alternative?  If I am conducting a study to determine the numbers of
species of trees present in a forest community (or grasses/forbs in a prairie
community, etc.), what should I use if not a morphospecies criterion?  Am I
supposed to collect tissue samples from every individual sampled, return these
to the lab, use some technique such as as isozyme, RFLP, RAPD, etc. analysis to
develop a profile for each sample, and then determine the number of species

In reviewing manuscripts over the years, I have encountered authors who argue
against a morphospecies concept because their data (any of a variety
biochemical data, e.g., phenolic compounds, isozymes, other molecular tools)
indicate that the species limits are not coincident with patterns of
morphological differences.  Interestingly, when I asked them how they
determined which specimens they used to identify their samples, they had to
admit that they used a morphological criterion to establish the pooled samples
for their analyses.

I will be the first to admit that the morphospecies is not necessarily the best
concept to use for evolutionary studies, but when one is conducting
biodiversity surveys, I see little in the way of a *practical* alternative.  I
do agree that attempts to use higher levels are flawed given the rather
arbitrary criteria by which genera, families, etc. are defined.  Is the genus
Juglans (walnuts; about 14 species) equivalent to the genus Quercus (oaks; at
least 400 species)?  I suggest not.  Besides, in order to use both extant and
extinct species to evaluate historical patterns, our hands are virtually tied:
we must rely on morphospecies for the vast majority of extinct taxa.  For the
comparisons to be valid, this means that we must use the same criterion for
evaluating extant taxa.  It would make no sense to claim that the number of
species of hawthornes present in paleobotanical samples, recognized on the
basis of morphological characters, is either more or less than the number
present in extant communities, based on some other species concept.  A valid
comparison for the two data sets requires that the same rules (i.e., species
concept) be used for determing the diversity in each sample.

Richard J. Jensen              TEL: 219-284-4674
Department of Biology      FAX: 219-284-4716
Saint Mary's College         E-mail: rjensen at saintmarys.edu
Notre Dame, IN  46556     http://www.saintmarys.edu/~rjensen


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