[Taxacom] Why character-tracking doesn't happen?

Thomas G. Lammers lammers at uwosh.edu
Fri Sep 12 11:23:05 CDT 2008


At 10:34 AM 9/12/2008, Neil Bell wrote:
>Like any methodology it makes assumptions appropriate to the questions
>it is trying to answer.

My opinion is that making assumptions that conflict with reality is not 
likely to generate much of value.

>Aggregations of individuals and populations (generally and eventually, if 
>by no means always) become discrete units through the process of speciation.

No.  I do not accept the "reality" of species.  They are an aggregation of 
convenience.  Even populations can be of dubious reality.  The only reality 
is the individual.

>Incomplete lineage sorting and reticulation occur and should be 
>identified, but they are not the
>dominant patterns in the relationships between phylogenetically distant 
>eukaryotic organisms.

Guess you've not worked with angiosperms, huh?

>Population genetics can say no more about the relationship between a frog 
>and a sparrow than cladistics can about the relationship between 
>individuals within a population (probably a lot
>less actually).

I accept that different levels of the hierarchy have different appropriate 
approaches.  Phenetic approaches are useful for sorting individuals and 
populations into species and subspecies but are inappropriate at higher 
levels.  Nonetheless, cladistics purports to represent the *patterns* of 
evolution; are those patterns not driven by processes at the level of 
individuals and populations?  If so, should their be such a profound 
disconnect between them?   If a genealogy purports to show a family tree, 
would it make sense to have it ignore the processes of marriage and 
childbearing?

>I always find it odd when people criticise cladistics and/or
>phylogenetics without suggesting how the questions they ask could be
>better answered. The implication seems to be that either 1) the
>questions are unanswerable 2) they are not interesting, or 3) there must
>be better ways to address them but we don't know what they are...

I don't think there is a better methodology than cladistics for answer 
relationship questions above the level of species.  Flawed though it is, it 
is the best possible.  My problem is with those who ascribe FAR too much 
value and import to their imaginary stick figures, who paint themselves 
into ridiculous corners because they do not view cladistics as a tool but 
rather as a religion to be adhered to steadfastly.  The refusal to accept 
paraphyletic taxa is the most blatant example of a priori philosophy 
dictating counter-productive results.  I know a reptile or a fish when I 
see one, and the fact they are defined on the basis of plesiomorphies 
bothers me not one whit.

Classifications, IMO, should take into account cladistic relationships, but 
they should not mirror them slavishly.  If a more useful classification 
obtains through recognition of paraphyletic taxa, or by not giving sister 
taxa equal rank, so be it.


Thomas G. Lammers, Ph.D.

Associate Professor and Curator of the Herbarium (OSH)
Department of Biology and Microbiology
University of Wisconsin Oshkosh
Oshkosh, Wisconsin 54901-8640 USA

e-mail:       lammers at uwosh.edu
phone:      920-424-1002
fax:           920-424-1101

Plant systematics; classification, nomenclature, evolution, and 
biogeography of the Campanulaceae s. lat.

Webpages:
http://www.uwosh.edu/departments/biology/Lammers.htm
http://www.uwosh.edu/departments/biology/herbarium/herbarium.html
http://www.ratemyprofessors.com/ShowRatings.jsp?tid=297234
http://www.kewbooks.com/asps/ShowDetails.asp?id=615
http://www.uwosh.edu/colleges/cols/StaffBooks/lammers.htm
http://www.geocities.com/TheTropics/Resort/7156/lammers.html
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