More on the 'cladistics' of sequences

John Grehan jgrehan at SCIENCEBUFF.ORG
Wed Jun 9 11:49:26 CDT 2004

-----Original Message-----
From: Taxacom Discussion List [mailto:TAXACOM at LISTSERV.NHM.KU.EDU] On
Behalf Of Richard Jensen
Sent: Tuesday, June 08, 2004 1:13 PM
Subject: Re: [TAXACOM] More on the 'cladistics' of sequences

I believe impute is the wrong word here.  I am simply deducing, based on
statements you post, what you do and don't appear to understand about
cladistic methodology.  When someone makes simple statement that is
and you reject it, then I can deduce that you either don't understand or
are being a gadfly.

Or the statement itself was problematic

Richard Jensen wrote:

Uninformative characters are ignored because they don't provide any
information about sister-group relationships.  I don't have to be a
hominid systematist to take a look at a data matrix and tell you whether
a character is informative.

John Grehan replied:

Only in the context of the data matrix. Whether the characters are
really any good is another matter.

It has nothing to do with the data matrix.  A character that is
identical in
all taxa in the analysis is uninformative and characters that are true
apomorphies are uninformative.  And this applies to both molecular and
morphological data.

I have not problem with this, only the issue of whether characters are
informative or not depends on which characters are included in the
matrix in the first place.

Maybe I'll take your advice and just ignore your future postings; then
can claim that you are not getting a fair hearing because no one will

If you like, although I doubt there is such a thing as 'fair hearings'
in science. What might be fair to one might not be to another.

With all due respect,



John Grehan

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