[Taxacom] Order Campanulales (worth maintaining?)

[Richard Zander]

Curtis:

Much of my response to you is the same as I wrote to Chris regarding
Jesus-in-a-taco. 

We work with theories that fit into other theories, investigatin best or
more parsimonious theories first. Also, we can get feedback or
reciprocal illumination when working with one theory gives garble and
another theory seems more sensible. Then we rely for further work the
theory that predicts, explains and helps facilitate research best. (This
is of course standard and what you already know. I'm also writing for
students.)

In addition, I promoted in that response the idea that biosystematics
can help firm delimitation of clusters of specimens "out there" and
clusters of clusters of specimens, using ordination, cluster analysis,
cytology, and the usual list of analytic tools of biosystematics.

One can specify a circumscription and then investigate how an entity of
that circumscription may have evolved or is evolving. If nonsense
results, then try another circumscription. This is the process of
scientific theory-testing, and is absent in "evolutionary" studies done
by phylogeneticists, who merely map other data on a cladogram. (A
simplistic condemnation since no phylogeneticist is really purely
pattern.)

So you specify the circumscription as a theory, not a fact. A cladogram
is a fact (of OTU similarity), and perhaps you are used to cladograms
presented as theories? Regarding your question do I allow unranked taxa
to evolve, there is an element of hyperrealism implied in that. One can
investigate anything natural without worrying what its rank is. Even
more important is that the methods of alpha taxonomy should not be used
for determining theory that is better investigated by biosystematics. 

Re ranks biologically meaningless, if you only recognize nesting as
biologically meaningful, then sure. But nesting as synchronic clustering
of present-day OTUs is not the only biologically meaningful analytic
procedure for evolution. You can infer diachronic macroevolution. And
signal theoretical macroevolutionary events by rank. Cactaceae emerged
from Portulacaceae. Rank matters in evolution unless you demand
theory-free analysis. Without rank mattering, then you do not have the
NAMES needed for even thinking about theoretic macroevolutionary
concepts, which is a terrible way to enforce group-think.


On 2011-02-19 15:03, Richard Zander wrote:
> Genera are non-arbitrary because we see them, apprehend them, grok 
> then, vasten them; even Aristotle recognized genera, Linneaus 
> incorporated them into his very names for species. I think it is up to

> you to subject taxa to a statistical analysis that shows that genera 
> are arbitrary and merely random groups of vaguely similar species.
Okay, I'll try one more time before I drop it.

Although I can't think of one off the top of my head, there are a number
of genera among the flowering plants, and no doubt elsewhere, that have
both sensu stricto and sensu lato circumscriptions that are widely
accepted. Whether one accepts the one or the other in each of these
cases is most often informed by past practice, one's taxonomic milieu,
the manuals in use for one's region, and other factors that don't relate
directly to any traits of the genera or their component species and
populations, or to any theories about their origins.

So I'm not saying that the generic circumscriptions are arbitrary, but
rather that the choice between them is arbitrary. And in a similar
sense, I'm saying that the taxa aren't arbitrary, but their ranks are.

Taking, for now, at face value your assertion that genera evolve, how
can you even address this without specifying the circumscription? And if
you specify the circumscription, why does the rank even matter except
for naming purposes? And do you deny unranked taxa the ability to
evolve?

This started out with my assertion that ranks (not taxa) are
biologically meaningless for anything other than specifying nesting
(with the exception of species, which I will defend but many won't). 
Although again many will disagree, I fully accept that taxa can evolve. 
You have not convinced me that the rank or lack of rank of a taxon has
any bearing on this.

--
Curtis Clark
Cal Poly Pomona

 
* * * * * * * * * * * * 
Richard H. Zander 
Missouri Botanical Garden, PO Box 299, St. Louis, MO 63166-0299 USA 
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