[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: replying to pomposity (classificatory schemes)



In a message dated 6/20/00 9:13:09 PM Pacific Daylight Time, 
kinman@hotmail.com writes:

> The most important lesson I learned 
>  from Peter Ashlock was that cladistic analysis is a very powerful tool 
when 
>  done correctly, but the translation of cladograms directly into purely 
>  cladistic classifications (cladifications as Ernst Mayr calls them) can 
>  never produce stable, useful classifications in the long term.

There is no such thing as a cladistic classification.  Cladistics is a method 
(and a fallible one, at that) for determining relationships between 
organisms.  Many cladists in practice use phylogenetic taxonomy, in which 
clades are defined by their common descent with or relative proximity to 
particular "anchor taxa".  

I have some very serious reservations about using rigid phylogenetic 
taxonomy, as in many cases we are uncertain enough of the relationships in 
question as to make the composition of these phylogenetically-defined groups 
very labile.

On the other hand, I (and I am strictly a non-professional, a graduate 
student in another field of inquiry) do insist that my classificatory groups 
be monophyletic.

>From quite a young age I always assumed that the names given to groups were 
as accurate a representation as we could give of the evolutionary 
relationships of organisms, and I was quite surprised (and even felt somewhat 
betrayed!) to learn that there were a number of names out there, like Pisces, 
Condylarthra, and Thecodontia, that were masking known connections to other 
groups.

Blame where blame is due, please--and the same with credit.

Nick Pharris