[Taxacom] Order Campanulales (worth maintaining?)
Richard.Zander at mobot.org
Sat Feb 19 17:03:15 CST 2011
O for a simple arguable question rather than the tedious cut and thrust of ad hominids. Doubtless someone may learn something from this exchange, about arguing.
A Departure from Biology is an opinion. Yes, okay, I agree. But how did I depart from biology?
You say you demolished my theory of how genera might evolve because I was apparently unable or unwilling to address your question of differing evolutionary rates of split versus lumped genera. Aha! maybe so! Now that I think of it, you are posing the problem of how I might parallel the accepted theory that small populations evolve faster than large populations (there's an equation in there somewhere involving e), given no genetic exchange between species in an evolving genus and hence no drag to drift. Well, maybe one might postulate (and someday test) environmental effects on small versus large genera. I would think that small genera would evolve faster than large because there are fewer species that might be affected through natural selection on each species by a single environmental variable. Larger genera would have a larger range of variability and thus would evolve as a unit more slowly.
This is not to say I imagine species are individuals, but in some cases they may be treated as such heuristically. Thus, drift among species of a genus may act in the same manner as drift within a species. I'm not a population biologist, anybody with an opinion?
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.
Re my supposed stock formula, what a good idea! a key board macro! I try to repeat my ideas, yes, because it works. Remember that "parsimony" as a formula, slogan or axiom has been repeated so often that most accept that "most parsimonious" morphological cladograms are actually most parsimonious because they are shorter in numbers of steps. Nonsense! A most parsimonious cladogram would be one with a minimum of hypothesized extra entities as "shared ancestors" because any split could have been an ancestor-descendant split for which a shared ancestor is unnecessary. Non-phylogenetically-informative data might give information on the possibility of one or the other post-split lines being a surviving ancestor, and make a cladogram more parsimonious, given 1. estimates in the literature than ancestor-descendant splits are common, and 2. traits are EITHER conservative and thus relatively nonselective OR fixed as a group and therefore should be taken as a single trait in morphological cladograms. This allows slack for longer cladogram that are more parsimonious with postulated shared ancestors. About the same is true for "most parsimonious" molecular cladograms given that taxa with phenotypic traits under stabilizing or disruptive selection are somewhat disconnected from splits in molecular gene histories.
I, too, find grouping by homology okay. As part of a larger effort to understand descent with modification.
Well, sure I've made up my mind about you, Curtis. You are one of the more readable and interesting of the contributors to Taxacom, and your comments are always interesting or challenging.
How to "repair the genera circumscribed by others to make them scientifically meaningful." Umpf. Sometimes one just goes with a "best" circumscription and see where analysis leads. A badly circumscribed genus may give more poor results, or some obvious nonsense, than one better circumscribed. This kind of testing of alternative theories is difficult to imagine in phylogenetics, where the main concern is whether the cladogram is well-supported by data about sister-groups, and geography or environment, for example, is simply mapped on a cladogram.
Oh, sure I'm being simplistic. Nobody but certain panjandrums and magnificoes are pure pattern cladists, and phylogeneticists are commonly good taxonomists with an interest in population genetics and the like.
Richard H. Zander
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166 U.S.A.
richard.zander at mobot.org
From: taxacom-bounces at mailman.nhm.ku.edu on behalf of Curtis Clark
Sent: Fri 2/18/2011 8:47 PM
To: taxacom at mailman.nhm.ku.edu
Subject: Re: [Taxacom] Order Campanulales (worth maintaining?)
On 2011-02-18 15:52, Richard Zander wrote:
> Note that your response to my argument accused me of a Departure from
> Biology, which I believe is an axiom or at least a scary pronouncement,
Sometimes an opinion is just an opinion.
> and you ignored my theory of how genera might evolve,
There is no theory. I demolished it with your inability or unwillingness
to address the evolutionary rates of split versus lumped genera. It was
not rhetorical, and while it was sarcastic, that was predicated on my
expectation that you would be unable or unwilling to answer it.
> which is an avoidance of theory typical of structuralist nonscience.
QED. I dismiss your remark because you have not provided evidence that
genera are generally non-arbitrary. You dismiss my remark by applying a
stock formula that you have used so often that I wonder if you have a
> Also, I will play on any playing field (i.e. discuss constructively
> any alternative theory) but that of structuralism (such as theory-free
> discovery-process analysis).
As you define it. QED again.
> You probably did not mean lapses, and if I have harped in the past on
> a theme based on some word you may have inadvertantly used instead of
> a more appropriate word, I apologize.
I find grouping by shared homology to be useful. You accuse me
(specifically, by lumping me with all cladists) of some sort of
structuralist heresy. I'm annoyed by that, and it makes me unwilling to
discuss things with you, since you have already made up your mind about me.
And now that I think about it, your grouping me with "cladists", absent
any expressed theory, seems rather structuralist. Perhaps you have a
theory. Could it be falsified by evidence from my actual intellectual
history, and the factors that shaped it?
> You could have said, well, give me an example of a genus that has
> apparently evolved.
To me, that is a meaningless question, since the rank of genus is (IMO)
in practice arbitrary.If you circumscribe non-arbitrary genera, then
huzzah. I'd be interested to know how you can repair the genera
circumscribed by others in order to make them scientifically meaningful.
If you can explain that, then perhaps we can move on to your question.
Cal Poly Pomona
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