Ernst Mayr and "Life"
kinman at HOTMAIL.COM
Mon Sep 13 22:05:41 CDT 1999
I very seriously considered the global classifications of
Cavalier-Smith, who is probably one of the most brilliant biologists in the
world today. I think there have been several versions, from about 7 to 9
kingdoms (the majority being among the protists). Unfortunately, even his
system has been unraveling in recent years. Chromista is coming apart, and
his Archezoa (which I unfortunately followed, under the name
Archaeoprotista) is faltering with evidence that there are few (if any)
eukaryotic groups that are primitively amitochondriate. The Hydrogen
Hypothesis (Martin and Muller, 1998) would essentially equate the origin of
the mitochonrion with the origin of eukaryotes (and thus my reason for using
the phrase "if any" in the preceding sentence.
Even before these problems, Cavalier-Smith had paraphyletic kingdoms in
his system anyway, so why should one split up Kingdom Protista into a system
of less certain kingdoms if he admitted that paraphyletic taxa were
inevitable anyway. His systems were well thought out, but never convincing
enough to me to warrant a more complex classification and potentially
unstable classification (and the problems that have arisen only confirm that
in my mind).
I think my views on Three Domains are pretty well known so I won't
belabor the horrors of that system. I agree with the criticisms of Mayr,
Margulis, and others, with some additional reasons of my own, which I have
elaborated on before.
The only two systems which I have ever seen that really made sense to
me, are the Four Kingdom and the Five Kingdom Systems. The well-known
Five-Kingdom System of Whitaker (and Margulis) is still extremely popular,
but I never adopted it. Rather I prefer what immediately preceded it, the
Four Kingdom System, before Whitaker raised "Fungi" as the Fifth Kingdom.
The Four Kingdom System was the result of splitting the Monera off from
the Protista. Monera gives rise to Protista, which in turn gives rise to
Metazoa and Metaphyta. A. J. Cain used this system in the Encyclopaedia
Britannica (1975), even after Whitaker had proposed the 5 Kingdom System.
Raising "Eumycota" to the status of a fifth kingdom might have made a bit of
sense, but raising a polyphyletic taxon "Fungi" was a terrible error. This
has been the source of a great amount of confusion ever since. Therefore, I
have always used the 4 Kingdom System, and have never had any regrets in
using it in my 1994 book (The Kinman System: Toward A Stable
Cladisto-Eclectic Classification of Organisms).
Four Kingdoms are stable, easy to teach and learn, and Phylum Eumycota
falls totally within Kingdom Protista , whether or not you include chytrids
within it or as an external ancestral group (take your pick). I have no
major problems with recognizing a fifth kingdom, but for heaven's sake, call
it Eumyota, not Fungi (since the latter is quite polyphyletic). Another
good reason for including eumycotans in Prostista is that they need to be
included with them for comparative purposes anyway, so why split them off
when all it does is tempt too many to include unrelated "fungal" groups just
because they share a saprophytic nutritive mode.
My choices are therefore: (1st) 4 Kingdoms; (2nd) 5 Kingdoms; (3rd)
Cavalier-Smith's systems (take your pick); and (last) Three Domains (which
is now simultaneously one of the most loved and hated systems, and in my
opinion an unfortunate fad of the 1990's that will go the way of pet rocks).
Even the problems of Cavalier-Smith's systems are miniscule compared to
what will no doubt be found with the Three Domain System once it is
critically evaluated in a proper context in the coming years. As I have
said before, even Woese (Sept. 1998 in PNAS) seems to be so painted into a
corner, that he is backtracking towards his discredited Three Urkingdoms.
It may seem a bit mean-spirited to keep criticizing his paradigm, but it
would be worse to allow one scientist's views to impede science and
potentially affect the well-being of many others that science could help
(medically, and in other ways) without the problems such intellectual
strictures impose. Although, the debate between Mayr and Woese (in August
and Sept. 1998, Proc. Natl. Acad. Sciences) has been almost totally ignored
in this forum, Mayr and Woese themselves agreed on one thing---that the
results of their debate would have profound implications for the future of
all science (and biology affects all the sciences, in one way or another).
>From: "Susan B. Farmer" <sfarmer at GOLDSWORD.COM>
>Reply-To: "Susan B. Farmer" <sfarmer at GOLDSWORD.COM>
>To: TAXACOM at USOBI.ORG
>Subject: Re: Ernst Mayr and "Life"
>Date: Mon, 13 Sep 1999 21:47:52 -0400
> >At 09:43 AM 9/13/99 -0400, Les Kaufman wrote:
> >>I think Ken is right about the three domains. It is now being taught as
> >>dogma in intro bio in many places.
> >Much like the five-kingdom scheme, which is as misleading.
>For those of you who don't like the ever-popular Five Kingdom Scheme,
>which version of a Global Classification do you prefer?
>sfarmer at goldsword.com
>Botany Department, University of Tennessee
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