[Taxacom] Usefulness vs. convenience (Protista)

Dick Jensen rjensen at saintmarys.edu
Sun Dec 19 13:50:40 CST 2010

Zack and Kleo,

Seems to me that the usefulness of a classification is a function of what the user wants to know.  If one is primarily interested in knowing hypothesized evolutionary relationships, then a classification designed to show that is preferable.  But, if one's primary interest is in knowing, for eample, which species of oak is most likely to be confused with the species I am interested in, then the best classification may be one that is based on overall similarity (dare I raise the spectre of phenetics?).  When I correspond with botanists who are trying to make sure the specimens they have are correctly identified, they don't care about sister species or clade relationships; they want to know how to differentiate between, e.g., Q. rubra, Q. shumardii and Q. texana, which probably are not a three taxon clade in the genus.

As I see it, we taxonomists often do our discipline a disservice by ignoring what non-taxonomist users want or need. There is no reason why we should demand that our classifications reflect *only* evolutionary relationships and the rest be damned! Clearly, evolutionary relationships are important for our understanding the history and diversity of life.  But these are hypothesized relationships based on particular algorithms chosen by investigators who have a particular view of how evolution proceeds.  I can't avoid a feeling of deja vu - these were much the same criticisms leveled at numerical taxonomists and they apply to modern cladistic approaches as well (e.g., numerous posts by Zander and others).


Dick J   

----- Original Message -----
From: murrellze <murrellze at appstate.edu>
To: Kleo Pullin <kleopullin at pacbell.net>
Cc: taxacom at mailman.nhm.ku.edu
Sent: Sun, 19 Dec 2010 14:10:00 -0500 (EST)
Subject: Re: [Taxacom] Usefulness vs. convenience (Protista)


I can't answer your questions, but I am struck by the usefulness of this 
discussion in pointing out that 1) classifications are most valuable 
when they reflect our knowledge of evolutionary history and 2) the 
Phylocode is the best way we currently have to reflect evolutionary 
history in a classification system. 

The Linnaean classification system is woefully inadequate, as 
demonstrated in this discussion thread.  Why are we attempting to 
classify life in the 21st century without including our understanding of 
the "tree of life"?

Zack Murrell

Kleo Pullin wrote:
> I have a few questions about this discussion:
> 1. Why/how/for what is Protista more useful or convenient?
> 2. And what is the difference between usefulness and convenience--this thread is titled "Usefulness vs. convenience?"
>>>		 As for rhodophytes (and glaucophytes),
> Cavalier-Smith includes them in a very broad Kingdom Plantae. Others
> have left them in Protista, but included green algae in Plantae (making
> it equivalent to Viridiplantae). 
> 3. Who has left rhodophyta in the Protista?
> Thanks,
> Kleo Pullin
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