Re: Cladobabble

["Jerry D. Harris" <dinogami@hotmail.com>]

>         Of course it would. However, consider the follwing (excessive) 
> example:
>         Character list one:
>         Give milk to young: 0) no, 1) yes
>         Loss of egg:    0) no, 1) yes
>         Number of legs: 0) four, 1) two
>         Number of feet: 0) four, 1) two
>         Number of appendages not used for ground movement: 0) zero, 2) two
>
>         Taxa: Ursus arctos, Homo sapiens, Columba livia
>
>         Guess what, you have discovered a human-bird clade. Never mind 
> that
> the last three characters are all manifestations of the same phenomenon
> (bipedality), so say I, anyway.

  Again, this is the problem with overly-general characters.  Yes, 
bipedality is shared, but how do each of these organisms achieve bipedality? 
 Unless all the bones, muscles, etc. that allow each of these organisms to 
locomote bipedally are identical (or at least very similar), I'd say (as 
would you and everyone else, I'm sure!) that this clade would fall apart 
with even a cursory analysis of the nuances (especially between the bird and 
the mammals).  An analysis can easily be forced in a particular direction by 
overly-general characters, because the analysis itself cannot "see inside" 
the characters and make assessments based on them -- it can only deal with 
that which it has been given.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jerry D. Harris
Dept of Earth & Environmental Science
University of Pennsylvania
240 S 33rd St
Philadelphia PA  19104-6316
Phone: (215) 898-5630
Fax: (215) 898-0964
E-mail: jdharris@sas.upenn.edu
and     dinogami@hotmail.com
http://www.sas.upenn.edu/~jdharris

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