Clades, cladons, and "cladifications"

[Richard.Zander at MOBOT.ORG]

-----Original Message-----
From: Nico Mario Franz [ mailto:nmf2 at CORNELL.EDU <mailto:nmf2 at CORNELL.EDU> ]
Sent: Tuesday, June 15, 2004 2:04 AM
To: TAXACOM at LISTSERV.NHM.KU.EDU
Subject: Re: [TAXACOM] Clades, cladons, and "cladifications"




I have to disagree. Consider a larger cladogram with a sequence of 5 basal
bifurcations. Their respective supports are number of 1, 1, 10, 1, and 1
synapomorphies. There is nothing in cladistics that would force me to make
the "cut" for a rank (say, a subtribe of insects) at the least supported
rank. If I want my cladistic subtribe to communicate a lot of evolutionary
differences, I'm free to let it have 10 synapomorphies, not just 1.


A picky query regarding the phrase "a lot of evolutionary differences."
Whether 10 is a lot is relative to support for alternative arrangements of
branches on the internode. There are three possible arrangements, of which
one in this case has 10 steps. Perhaps the two alternative arrangements are
each supported by 9 steps. Thus, if the other 4 other arrangements are not
contradicted by any support for alternative arrangements, support of 1 is
about as high as support of 10.  The subtribe would then not communicate a
lot of evolutionary differences.



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Richard H. Zander
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