Real taxa => Ranking

Dr. James Adams jadams at EM.DALTONSTATE.EDU
Tue Sep 28 15:29:41 CDT 2004


         I was going to stay out of this discussion, as the "species"
question has been discussed ad nauseum (emphasis on the nausea), but I
couldn't let this one go.

Christian Thompson wrote:

>I was surprise to read:
>How to select the "appropriated" taxonomical rank (genera, tribe etc)
>for agroup is a matter of debate, mainly because this issue is out of the
>scope of the formal methods of systematics (cladistics).
>Willi Hennig himself clearly proposed an objective method of ranking
>years ago [snip]: he stated the proper criterion for rank was age of the

Although technically "objective", this would be, as Christian went on to
explain, a ludicrous way to assign higher level taxonomic rank as
generation times differ by orders of magnitude between bacteria and
Galapagos tortoises, between algae and Agaves, and doesn't take into
account stability of environmental conditions through time.

I know I didn't really need to say this to most of you, as it is
obvious.  Assigning higher taxonomic rank will *always* be subjective,
because the higher rankings are *constructs* of *humans* attempting to
indicate some level of evolutionary relationship.  The key item here is
that *humans* are involved in the process of naming, so it can't be objective!!


James K. Adams
jadams at
Phone: (706)272-4427
FAX:  (706)272-2235
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