polarized and unpolarized

[Ken Kinman]

Gianluca,
      Just a quick response (past my bedtime and my brain is already half
asleep).  :-)
     Most characters are multistate, and to polarize them (for simplifying
character matrices or even for identification keys), one generally lumps all
the states into one of two ("bipolar") states.
      For example, character X may have a wide range of values (multistate),
but you can polarize it with a ratio to get just two states.  For example
length of bone X is:
  (1) greater than length of bone Y;
or (2) lesser than or equal to length of bone Y.
      Some characters are very easy to polarize (such as: structure present
or absent), but most have a continuum of many values, and those must be
somewhat arbitrarily divided in order to produce two "polar" states.  Some
characters are difficult to polarized, but I'm too tired too think of any
good examples (a structure that comes in different colors might be one
example, although you could arbitrarily divide it into something like "red
vs. not-red").
         ---- I'm off to bed,
                       Ken
*****************************************
>From: Gianluca Polgar <polgar at ALFANET.IT>
>Reply-To: Gianluca Polgar <polgar at ALFANET.IT>
>To: TAXACOM at USOBI.ORG
>Subject: polarized and unpolarized
>Date: Sun, 6 Jan 2002 05:39:48 +0100
>
>Dear taxacomers,
>
>At first I'd like to say thanks to Ken for his soonest reply.
>My problem is that a lot of my texts is in italian (I'm italian) and I need
>to understand the meaning of english terms when I find any in an english
>publication.
>I have another question for you.
>What's exactly the difference between a polarized and an unpolarized
>character?
>
>
>Thanks
>
>Gianluca Polgar
>polgar at alfanet.it

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