revolution

Tom DiBenedetto tdib at UMICH.EDU
Thu Oct 3 07:45:30 CDT 1996


On Thu, 3 Oct 1996 09:41:54 -0500 (EST), Richard Jensen wrote:

>I have to admit that if one substituted the word Phenetics for the phrase
>"Cladistic parsimony" below, then one does have a description of
>phenetics.  There is a tendency to forget that both phenetic and
>cladistics analyses start at the same points, generate the same kinds of
>data, and may be analyzed by a variety of procedures.  They both can
>claim objectivity, but they both have a large measure of inherent
>subjectivity - involving algorithmic options.  One way that they do
>differ, and this is a key difference, is that cladistics generally adds a
>layer between character description and analysis - hypothesized
>transformation series.
>> >
>> ><<   [[ Cladistic parsimony ]] ... approaches do not use
>> > a particular model of evolutionary processes, but rather incorporate
>> > relevant knowledge at a prior stage, at the level of formulating
>> > hypotheses of homology. The algorithm is left to function as an
>> > objective pattern-extractor from a data-set of characters which have
>> > already been accepted as homologous. >>

I disagree absolutely with this, There is no concept of homology in
phenetics, no vision of individual characters as marks of history,
and a reliance on measures of overall similarity. I dont know what
you mean that we "start at the same point",,,with organisms?
ok....The two approaches do not generate the same kind of data, and
in cladistics we do not analyze with a variety of procedures.
---------------------------------------------
Tom DiBenedetto
Fish Division
Museum of Zoology
University of Michigan




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