[Taxacom] cladistic analysis for morphological characters

John Grehan calabar.john at gmail.com
Sat Nov 10 17:33:58 CST 2012


And there is also the consideration of how many of those characters are
used to define the monophyly of the group being analyzed since they will be
uninformative about the interelationships within the group. Hopefully the
character states used to identify those interelationships are properly
apomorphies - i.e. the derived states are clearly limited to the ingroup
and if they constitute measurements they do not fall within the range of
outgroup taxa. Quantity is not everything (but that's all that the
algorithms measure). Quality is critical.

John Grehan

On Sat, Nov 10, 2012 at 5:49 PM, Jan Bosselaers <dochterland at telenet.be>wrote:

> Dear Sami,
>
> It is often stated that it is best to have about three times more
> morphological characters than taxa, but that is not an absolute necessity.
> As soon as you have about twice as many characters than taxa, as in your
> case, the matrix is worth a try. Much depends on the ratio between binary
> and multistate characters, the way characters are scored and whether you
> use a weighting scheme, such as implied weighting, or not. I just finished
> an analysis on 42 taxa and 82 morphological characters and obtained a
> consensus of nine trees with a consistency index of 0.648, while Sanderson
> & Donoghue (1989) Evolution 42: 1781-1795 predict a ci of 0.351 for such a
> data set. So give it a try, and when it does not work out properly, do what
> Kluge said: go back to the data and check all your scores.
>
> Best regards and success,
>
> Jan Bosselaers
>
> > Dear All
> >
> > I have 81 morphological characters for 44 species. it is right to make a
> cladistic analysis for them. If it is ok which program I can use it.On the
> other hand I did UPGMA .
> >
> > Many Thanks in advance
> >
> > All the best.
> >
> > Sami Rabei
> >
> > http://mansoura.academia.edu/SamiRabei
> >
> > ----------------------------------
> > With my Best Wishes
> > Sami Hussein Rabei, Ph.D.
> > Botany Department
> > Faculty of Science,
> > Damietta University
> > New Damietta , Post Box 34517
> > Damietta
> > Egypt .
> >
> > Tel. Mobile:   002 0127 3601618
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> >
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