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Re: Deep Scaly Project
Thanks for debunking the magic, Tom.
I never heard of Wiens's work until a reviewer was shocked that had not
referenced it. Now I've heard its praise and a cautionary
note. All part of my education.
"Thomas R. Holtz, Jr." wrote:
> > From: david peters [mailto:email@example.com]
> > Sent: Monday, May 16, 2005 5:36 PM
> > I can't tell you how much I agree with your thoughts here, Tom.
> > Re: the number of characters, I was wondering if you, or anyone else, had
> > any thoughts concerning Chippendale and Wiens
> > 1994 (Systematic Biology 432: 278-287) theoretical work that seemed to
> > indicate that only 150 or so characters were
> > needed to bring the probability of estimating correct phylogeny to the 95th
> > percentile (rapidly evolving characters),
> > while 300 skirts the 99th.
> In a word: EEK!!! The Bull et al. 1993 paper, to which the Chippindale &
> Wiens paper is a response and modification, is a simulation
> of molecular evolution in a FOUR TAXON tree!!! It isn't some figure which can
> universally be applied to all trees of all size. So
> no, 150 or 300 is by no means some magic number that can be applied to every
> To think about it a different way, the Deep Scaly Project matrix is about 150
> terminal taxa. Yet one would hope for more than 1
> character per node on a (e.g.) a fully pectinate tree.
> As for if I or anyone else had thoughts on the subject: the last decade's
> worth of Systematic Biology and Cladistics have had
> numerous articles in the "more characters vs. more taxa" (or "data density")
> sphere of discussion. I will say that as far as I have
> read, there is no resolution to a single magic answer. Just in general: data
> is good, more data is better.
> P.S. Weins himself is part of the Deep Scaly Project; his website of his
> publications is
> http://life.bio.sunysb.edu/ee/wienslab/publicationpage.html. On it are
> several papers relevant to this discussion.
> Thomas R. Holtz, Jr.
> Vertebrate Paleontologist
> Department of Geology Director, Earth, Life & Time Program
> University of Maryland College Park Scholars
> Mailing Address:
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