About dichotomy

Mr Fortuner connection modem fortuner at MATH.U-BORDEAUX.FR
Mon Mar 20 08:22:11 CST 1995

Rigor in Delta? I believe a better term would be rigidity.

In any cases, I
would like to ask a couple of question to Mike Dallwitz. When we met in 1990
(at the ARTISYST workshop in California), I asked you how I could enter
intraspecific variability using Delta (ISV, the percentage of individuals in a
species that exhibit a particular state of a character) and you said that this
type of information could be added to a "comment" field. Then I asked about
metadata and you said to put it in the comment field also, which would make it
kind of crowded.

The question is, is this still true or have you modified the
Delta standard to provide for ISV and metadata?

I see in your list of
requirements that a program should give "Similarities between taxa. Whether
the program can find the similarities between members of a set of taxa."

Excellent, but does this mean just the list of characters that are identical
in the unknown and a particular species, or are we talking of computing a
coefficient of overall similarity?

More generally speaking, is Delta still
doing dichotomous keys only (or variants such as multiple entry keys) or have
you moved to other methods of identification?

Even more generally, I am
curious to know what people think of dichotomy. I am asking Taxacom recipients
to answer the little survey below directly to my address. I'll compile the
results and post on Taxacom in about a week.

To make this more homogenous, I
am addressing this questionnaire only to people using identification methods
based on morphological characters (no molecular methods or limited methods
such as host specificity for parasite id).

Are you

How often do you do identification?
        once a
        once a month
        very rarely

What identification methods are you
        immediate recognition
        dichotomy or multiple entry keys
        Bayes' rule
        statistical methods
        other (explain)

Are you
using a particular method because:
        this is the one I prefer
        it stinks but
it's the only one available to me

Clip and return to the address below.

Renaud Fortuner
fortuner at math.u-bordeaux.fr

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