[Taxacom] Paraphyly/predictivity

Peter Stevens peter.stevens at mobot.org
Sat Mar 28 16:10:29 CDT 2009

Not to belabo(u)r the point, but let me repeat: thinking of common  
nouns and classifications, in folk classifications and in language  
generally, when nouns are members of contrast sets, they are  
generally non-overlapping - that is, one does not include the other.  
It clearly helps in communication.  This might be relevant when we  
are thinking of paraphyly and monophyly - [and autophyly].

As others have mentioned, classifications are for communication, and   
as such they should work within the constraints of language/ 

On Mar 28, 2009, at 2:01 PM, Richard Zander wrote:

> One of the points I've made in the past is that some changes made  
> in phylogenetic classifications are warranted by new information  
> about evolution or by well-supported corrections to previous wrong  
> classifications, AND some other changes are due solely to enforcing  
> classification by holophyly, which in my opinion suppresses  
> information on ancestor-descendant relationships as reflected in  
> classification by appropriate flagging with higher rank. Thus,  
> distinguishing which changes reflect fully what we think we know  
> about evolution and which changes reflect only what sister-group  
> analysis reveals about evolution will busy future taxonomists when  
> they should be doing other things.
> If the Epacridaceae turned out to be essentially the same as  
> Ericaceae (same diagnosis) then, hey, great. If on the other hand  
> Epacridaceae was an autophyletic taxon with significant  
> evolutionary features distinguishing it from the Ericaceae, then  
> not okay. The problem here is, as usual, that we don't know from  
> just the lumping WHY the two were lumped, but the latter reason, if  
> suspected, means that the Ericaceae in Australia might be of two  
> rather different evolutionary groups based on expressed traits.  
> What would an ecologist or evolutionist feel about loss of this  
> information? Possibly nothing because people in other fields have  
> not been warned that phylogenetic classification is for  
> phylogeneticists. Doubtless the answer is in the literature, but a  
> classification should be a précis of what we know about basic  
> taxonomic units and evolutionary groupings of them.
> *****************************
> Richard H. Zander
> Voice: 314-577-0276
> Missouri Botanical Garden
> PO Box 299
> St. Louis, MO 63166-0299 USA
> richard.zander at mobot.org
> Web sites: http://www.mobot.org/plantscience/resbot/
> and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
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> *****************************
> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom- 
> bounces at mailman.nhm.ku.edu] On Behalf Of Peter Stevens
> Sent: Saturday, March 28, 2009 1:06 PM
> To: Mike Dallwitz
> Subject: [Taxacom] Paraphyly/predictivity
> When I  was working on my thesis, it was a matter of some interest  
> that  Ericaceae (the rhododendron/blueberry/heather family) were so  
> poorly represented in Australia - except that it has turned out  
> that they  are very well represented there, but we were calling  
> them  Epacridaceae then, and so we thought that they were  
> irrelevant when  thinking about the distribution of Ericaceae...
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