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clarification of cladistic terminology



George claims:

> First, before the cladogram or any analysis, comes the observation
> of a character or character state. At this point, all we have are
> apomorphies.

The latter statement is at best confusing.  If you don't believe me,
stick in the term "plesiomorphy", "symplesiomorphy", or even
"synapomorphy" in place of "apomorphy".  They all make the same amount
of sense.  A character state is only an apomorphy (i.e. a derived
condition) with respect to other possible character states.  To say
that "all we have are apomorphies" is like saying every object in the
universe is at rest.  Relative to what?

Bottom line: character states are the only thing we observe.  Whether
or not a given character state is an apomorphy or plesiomorphy (i.e. a
primitive condition) is the subject of analysis and interpretation.

Norm asked: 

>> In other words, is the term "derived character" meaningless without
>> an assumption of phylogenetic significance?

Yes.  Irrespective of any confusion between the usage of the words
"apomorphy" and "synapomorphy", to call a condition "derived" makes no
sense outside of some assumptions about the phylogenetic significance
of that character state (i.e. the character's history).

>> If it is, what term could be used in its place that wouldn't
>> incorporate such an assumption?

The terms "character state" or "condition" entail no assumptions about
phylogeny.

-- 
Mickey Rowe     (rowe@lepomis.psych.upenn.edu)