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Re: Clade II



Jonathan Wagner wrote...
> >I. THE DUAL NATURE OF CLADISTICS
> >I feel these functions were confused in the debate on cladistics in November,
> >so I want to spell them out now:
>         Confused by you.  I tried very very hard to make the difference
> clear.  

    I don't agree.  See below.
 
>         De Queiroz, K., and Gauthier, J. 1990, Phylogeny as a central
> principle in taxonomy: phylogenetic definitions of taxon names. Systematic
> Zoology, 39:307-322
>         If you read this argue, and feel that you are well enough versed in
> philosophy, you may continue to debate this point.  

     Hey, thanks.  Working on it now.    

>         You miss the point.  If I can assume that there is a common ancestor
> of any group, I can say that there exists a set of animals which decended
> from that ancestor.  Read the ref.

     They descended, but they weren't a "set" until someone decided to
call them a "set".

> >ANCESTRAL SPECIES ARE PARAPHYLETIC
>         This is for others to debate.  At the species level, it may be
> impossible to form monophyletic groups.  Why should this prevent us from
> grouping those groups into monophyletic assembleges which are real entities?

     If some of the fundamental units of the clade aren't monophyletic,
how can the clade itself be monophyletic?  

> are looking at it the wrong way.  Don't ask why you can't make a parphyletic
> group because it was one monophyletic, ask yourself where the sense is in
> excluding some of the decendants of a once monophyletic group, thus making
> it paraphyletic.  Why would you do this?

      To emphasize other evolutionary phenomena besides common descent. 

>         If you wish to have your taxa have evolutionary meaning, then they
> must be devined (but not defined!) on the basis of shared derived
> characters, which you yourself have admitted is the best way to elucidate
> phylogeny.  

      This is EXACTLY what I was talking about before: the best means of
inferring phylogenetic relationships is not neccessarily the best means of
grouping (analysis vs. taxonomy). 
      Lets pretend someone found a series of historical documents written
in Ancient Egypt.  They all pertain to Ancient Egypt.  Some
have to do with war, some with agriculture, some with economics (subject).
Some were written by scribe A, some by scribe B, some by scribe C, who
lived at different times (author & time).  The translation of these
documents is what provides all of this information (which was done using a
variety of means).    
     So: of the following means of classifying these documents, which
makes the LEAST sense?:
      1. By subject
      2. By authorship
      3. By time period
      4. By how they were translated
     The best means of analysis is not neccessarily the best means of
classification.

>         Which can be easily summed up as them retaining the retentiion of
> the plesiomorphic state.  Note that by explaining it this way, we emphasize
> the EVOLUTIONARY aspects of the relationships and de-emphasize the
> SUPERFICIAL aspects (such as metabolism, behavior).

      Both of which, along with morphology, are directly linked, produced,
and modified by evolution.  I've never heared of evolution simply defined
as "the descent of one organism from another."  Darwin's term "descent
with modification" is better.  You are more then happy to use the
modifications to guide your analysis, why not consider them equally
important to guiding the taxonomy?

>         This certainly is sufficient answer to the Mayr quote.  The most
> important aspect of evolution is the description of phylogeny.  How else are
> we to determine the nature of adaptation (especially convergence and
> parrallelism) without first couching our arguments in the context of
> phylogeny?  
      
     None of which I am arguing with, I simply want to take it a step
further considering that branching and the creation of monophyletic
groups by extinction are the DIRECT RESULT of macroevolutionary phenomena.   
     Until I read the paper, I will decline further comment on the
subject, but for the time being my position is simply that:

1. All grouping of taxons are artifical, regardless of if they are defined
by common descent, morphology, ecology, etc...  This is probably the most
important point in my argument.  If you have any other "philosophical"
references that might be helpful on the subject, I would appreciate them.  

2. Taxonomy is not by definition based solely on common descent; that is a
cladistic interpretation, and in my opinion not as useful to the
evolutionist as one that also takes into account other macroevoltionary
trends besides common descent. 

LN Jeff
O-