[Taxacom] Species monophyly!

Sat Feb 6 14:08:36 CST 2010

Paraphyly of species might give problems in classification to
phylogeneticists but not others if paraphyly was persistent (no strong
drive to achieve reciprocal monophyly) for a long, long time and two
isolated populations were static in expressed traits but each changed
some in molecular traits through gradual accumulation of mutations that
are used to track lineages. Are they different? Yes. Are they different
species? Of course not but . . . 

>From a paper I have in consideration by a Very Good Journal:
"Reiseberg and Brouillet (1994) estimated that at least 50% of all plant
species are products of local geographic speciation and therefore
paraphyletic, and Funk and Omland (2003) found actual species-level
paraphyly or polyphyly in 23% of more than 2000 species sampled."

Funk DJ, Omland KE (2003) Species-level paraphyly and polyphyly:
frequency, causes, and consequences, with insights from animal
mitochondrial DNA. Ann Rev Ecol, Evol Syst 34:397-423
Rieseberg LH, Brouillet L (1994) Are many plant species paraphyletic?
Taxon 43:21-32

*****************************
Richard H. Zander 
Voice: 314-577-0276
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166-0299 USA
richard.zander at mobot.org
Web sites: http://www.mobot.org/plantscience/resbot/
and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
Modern Evolutionary Systematics Web site:
http://www.mobot.org/plantscience/resbot/21EvSy.htm
*****************************

-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu
[mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Stephen Thorpe
Sent: Friday, February 05, 2010 8:13 PM
To: J. Kirk Fitzhugh; TAXACOM
Subject: Re: [Taxacom] Species monophyly!

So ... when, if ever, would the non-monophyly of a species lead to a
taxonomic consequence (e.g., either lumping VERY morphologically
distinct populations together as one species, or else splitting
morphologically identical populations in order to preserve monophyly)?

________________________________
From: J. Kirk Fitzhugh [kfitzhugh at nhm.org]
Sent: Saturday, 6 February 2010 3:05 p.m.
To: Stephen Thorpe; TAXACOM
Subject: Re: [Taxacom] Species monophyly!

I wholly agree with you - monophyly is an irrelevant concept in this
instance. That simply goes without saying!

Along the lines of your argument, what has to be recognized is that
species hypotheses are inferred from theories that are not entirely the
same as those used to infer phylogenetic hypotheses. To his credit,
Hennig (1966) discussed at length seven of the different classes of
hypotheses often employed in biological systematics (cf. his oft
reproduced Fig. 6). It's obvious that inferences to these different
classes of hypotheses are by way of different sets of theories. Little
wonder that Hennig only spoke of monophyly as it applied to particular
**phylogenetic** hypotheses.

Kirk

Stephen Thorpe wrote:

I would try to argue that you are correct, species aren't individuals,
but nevertheless the concept of monophyly is still inapplicable to them.
I agree that species are nothing more than a literal family tree of
individuals with various relations of kin and similarity to each other.
My argument would be something along the lines of this: whatever species
are, the concept of monophyly arose from the desire to classify those
species in a "natural" (=nonarbitrary, =nonsubjective) way. Species are
to be classified into monophyletic groups (of species). But to apply the
concept of monophyly to species themselves, although possible, is
"changing the game", and has nothing to do with the task in hand. You
could try to argue on independent grounds that only monophyletic species
are "natural", and therefore to be preferred for the same reasons as
"natural" classifications, but if many of the best known species in the
world turn out to be paraphyletic (which could happe
n), and a monophyletic species concept leads to widespread
non-recognition of well-known species on morphological grounds (which it
might do), then we effectively kiss goodbye to the idea of species as
originally envisaged, and I don't see that as a worthwhile thing to do.
As an abstract example, imagine A, B, C as markedly and equally
morphologically differentiated allopatric species. Maybe C evolved from
a subpopulation of B, while A is sister to both. This would force you to
call B and C the same species, which just seems WRONG! Given that many
species are only known from one or a few specimens from which DNA cannot
be extracted, not to mention all the fossil species, I don't think we
want to say that the morphology could be leading us so far astray ... A
lion is a lion, and a tiger is a tiger, regardless of how the speciation
occurred ...

________________________________________
From:
taxacom-bounces at mailman.nhm.ku.edu<mailto:taxacom-bounces at mailman.nhm.ku
.edu>
[taxacom-bounces at mailman.nhm.ku.edu<mailto:taxacom-bounces at mailman.nhm.k
u.edu>] On Behalf Of J. Kirk Fitzhugh
[kfitzhugh at nhm.org<mailto:kfitzhugh at nhm.org>]
Sent: Saturday, 6 February 2010 2:24 p.m.
To: TAXACOM
Subject: Re: [Taxacom] Species monophyly!

This requires buying into Rieppel's conception of species. Something I
deny (cf. Fitzhugh, K. 2009. Species as explanatory hypotheses:
refinements and implications. Acta Biotheoretica 57: 201-248. See also
Stamos' "The Species Problem").

Species aren't individuals. If they were, then we'd not be reacting to
organisms by inferring what can only be regarded as explanatory
hypotheses, aka species and other taxa. Instead, we'd be speaking of the
properties of species, which we can't and don't.

Kirk

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
J. Kirk Fitzhugh, Ph.D.
Curator of Polychaetes
Invertebrate Zoology Section
Research & Collections Branch
Natural History Museum of Los Angeles County
900 Exposition Blvd
Los Angeles CA 90007
Phone: 213-763-3233
FAX: 213-746-2999
e-mail: kfitzhug at nhm.org<mailto:kfitzhug at nhm.org>
http://www.nhm.org/site/research-collections/polychaetous-annelids
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Stephen Thorpe wrote:

This is remarkably similar to what I was arguing on Taxacom a while ago:

Rieppel, O. 2010: Species monophyly. Journal of zoological systematics
and evolutionary research, 48: 1-8.
doi<http://en.wikipedia.org/wiki/Digital_object_identifier><http://en.wi
kipedia.org/wiki/Digital_object_identifier>:
10.1111/j.1439-0469.2009.00545.x<http://dx.doi.org/10.1111%2Fj.1439-0469
.2009.00545.x><http://dx.doi.org/10.1111%2Fj.1439-0469.2009.00545.x>
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