Assumptions and reliability of solutions

Richard.Zander at MOBOT.ORG Richard.Zander at MOBOT.ORG
Mon Mar 14 17:17:59 CST 2005

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,
(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 <mailto:richard.zander at>
Voice: 314-577-5180;  Fax: 314-577-9595
Bryophyte Volumes of Flora of North America:
Res Botanica:
Shipping address for UPS, etc.:
Missouri Botanical Garden
4344 Shaw Blvd.
St. Louis, MO 63110 USA

-----Original Message-----
From: E. Parmasto [mailto:e.parmasto at]
Sent: Monday, March 14, 2005 4:41 PM
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

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