----- Forwarded message from Joe Felsenstein <j...@gs.washington.edu> -----
Date: Fri, 29 Nov 2013 10:09:44 -0500
From: Joe Felsenstein <j...@gs.washington.edu>
Reply-To: Joe Felsenstein <j...@gs.washington.edu>
Subject: Re: cladistic vs phenetics method
To: morphmet@morphometrics.org
Shobnom Ferdous asked:
> We use cladistic method, some people use phenetics method for
> answering different questions. What do you think the major
> differences for those two methods, what can cladists do using
> phylogenetic method, that is not done by phenetics methods? Any
> thought or comments is much appreciated.
Please pardon me making one of my rants.
1. My own opinion:
It depends on what you mean by "cladistic" as opposed to "phenetic
methods". If the question is how to make a classification, these
adjectives are perfectly straightforward descriptions of approaches.
But if you are talking about different methods for inferring
phylogenies, or methods for making inferences about evolutionary
processes, one simply should not describe some methods as "cladistic"
and some as "phenetic", because they're not about classifications.
If one tries to use these labels, one ends up describing parsimony as
"cladistic", distance methods as "phenetic", but then likelihood and
Bayesian methods get described as one or the other, depending on who
is doing the describing. Or maybe they are cladistic on even-
numbered days and phenetic on odd-numbered days. Which just goes to
show that something is wrong with those designations in this case.
2. Everyone else's opinion:
They get mixed up between the two tasks (classification and
evolutionary inference) and end up taking an interesting discussion
of inferring evolutionary history, or inferring evolutionary
processes, and turning it into an exceedingly useless discussion of
classification. They also tend to (if they are "cladists") declaring
some methods of inferring phylogenies to be fundamentally wrong
because they are not "cladistic". Or if the people are pheneticists,
they tend to equate any study of phenotypes with being a validation
of a phenetic approach to classification.
So the issue is really: what is the question? If the issue is not
classification, can you ask the question again without using the
adjectives "cladistic" or "phenetic"?
Joe
----
Joe Felsenstein, j...@gs.washington.edu
Dept. of Genome Sciences, Univ. of Washington
Box 355065, Seattle, WA 98195-5065 USA
----- End forwarded message -----
