[Taxacom] Order Campanulales (worth maintaining?)
lists at curtisclark.org
Sun Feb 20 13:45:43 CST 2011
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.
Cal Poly Pomona
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