Assumptions and reliability of solutions

[Richard.Zander at MOBOT.ORG]

Well, you can get decent bootstrap proportions from a morphological data
set, often, by restricting the number of taxa to a small monophyletic group.
Since there are few characters, homoplasy outside monophyletic groups makes
bootstrapping problematic.

But in any case, branch arrangments on a morphologically based cladogram
that are distant on the cladogram are commonly considered reliable.
Resolution using morphological data sets is apparently low.

My point in my post was that, reliability measures (bootstrap proportions,
posterior probabilities) should be corrected for external assumptions. After
correction, I suspect, molecularly based cladograms will have almost as poor
resolution as the morphology based cladograms.

I might as well make another point here:
(1) you can struggle to find reliability measures for branch arrangements,
or
(2) you can do some "biosystematics" (remember biosystematics?) like common
garden or reciprocal transplant work (or whatever zoologists do that is
equivalent). It's too bad that work doesn't have the students or cachet it
once had. Lot of potential there to solve taxonomic problems.

______________________
Richard H. Zander
Bryology Group, Missouri Botanical Garden
PO Box 299, St. Louis, MO 63166-0299 USA
richard.zander at mobot.org <mailto:richard.zander at mobot.org>
Voice: 314-577-5180;  Fax: 314-577-9595
Websites
Bryophyte Volumes of Flora of North America:
http://www.mobot.org/plantscience/bfna/bfnamenu.htm
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-----Original Message-----
From: E. Parmasto [mailto:e.parmasto at zbi.ee]
Sent: Monday, March 14, 2005 4:41 PM
To: Richard.Zander at MOBOT.ORG; TAXACOM at LISTSERV.NHM.KU.EDU
Subject: Re: Assumptions and reliability of solutions


Richard Zander:
> The difference between a cladist and a non-cladist can be summarized
> in the following manner:
   etc., &c.
For me, the main difference is that probability /
reliability of the results of a cladistic study
(phylogenetic trees, resulting classifications, etc.)
may be somehow measured / characterized. What
about reliability of the results of a non-cladistic
study? Are there any good methods to evaluate the
probability of phylogenetic constructions /
hypotheses made by non-cladists (not including
pheneticists) ?
Erast Parmasto
******************