classifying life ("primitiveness")

Mon Apr 17 10:31:18 CDT 2000

Brian and other Taxacomers,
     I agree that the word "primitive" is often carelessly
overused, but I think that it is perfectly appropriate
here.  The word primitive comes from "primus", meaning
"original" or "the first of its kind".  Although there are
some who now believe bacteria are secondarily simplified, I think they are
wrong (and I should note that it is an entirely different matter that many
protists are secondarily amitochondriate, etc.; and certain subgroups of
bacteria like rickettsias are secondarily simplified).
      Prokaryotes (Monera) are a natural paraphyletic group, out of which
evolved the "chimaera" of the host eukaryotic cell and the mitochondrion
(and other organelles like chloroplasts and peroxisomes followed).  Instead
of celebrating the "primitive" importance of prokaryotes, Woesian ideas have
tended to obscure it.  I find that most unfortunate.  They are primitive in
the sense that they were a necessary precursor to eukaryotes, just as
amphibians preceded reptiles, and reptiles (in the traditional sense)
preceded birds and mammals.  And I am convinced Eubacteria preceded
Metabacteria (a.k.a. "Archaebacteria" or "Archaea") by many hundreds of
millions of years (perhaps a billion).
     I classify all prokaryotes in Kingdom Monera,
including viruses (which are clearly prokaryotic, even if
one doesn't consider them as a true life form).  It is true
that most living viruses are quite "modern", but I am
convinced that most (if not all) viruses have a history
that can be traced back (albeit with great difficulty) for
billions of years.  The viruses which pop in and out of
eukaryotic chromosomes today are probably highly evolved
descendants of "primitive" viruses that popped in and out
of prokaryotic cells long before eukaryotic cells even existed.
     That is one reason I erected a new Phylum Parabacteria
at the base of Kingdom Monera.  It contains all viruses and
progenotes (the latter are necessarily theoretical, but
they are very "primitive" eubacteria (sensu lato), and certainly nothing
like the peculiar Woesian concept of a progenote).  If we eventually find
that some modern viruses do not have an ultimate prokaryotic ancestry, then
those particular viruses should be classified with eukaryotes (but I
consider this highly unlikely).
    Modern bacteria are primitive in this same sense, even
if they are highly modified "modern" forms which are
adapted to today's biosphere.  Those who follow Woese (and even many who
don't) will fail to realize that tuberculosis bacteria of today are
descended from eubacterial forms
which probably existed long before Metabacteria ("Archaea") even evolved.
The latter probably evolved between 2.8-3.0
billion years ago, and the cyanobacteria and eubacteria
evolved about a billion years before that.
     The point that I am trying make is that although all
organisms today have an equally long ancestry (ultimately
descended from one group of progenotes), it is certainly  NOT true that all
crown taxa are equally old.  Precladistic trees like Haeckel's (or those
which show sponges and cnidaria at the base of Metazoan trees) must be taken
in a proper historical context.
     Strict cladists unfortunately have continued hurling the term
"gradistic" at anything that is paraphyletic, and many who are not strict
cladists sometimes now do the same.  The problem is that there are a lot of
babies in that
"gradistic" bath water, and I for one do not intend to
throw those babies out.
     And finally, I have had no problem reflecting the
diversity of prokaryotes in a single Kingdom Monera:
4 Phyla, 16 Classes, and 65 Orders were recognized in my 1994 classification
(for Monera).  I now recognize a few more Classes and many new Orders, but
there is plenty of room for expansion.  Woese clearly has overemphasized the
16S rRNA data (as important as it may be), and I think Bergey's Manual
editors will eventually regret having followed Woese's nomenclatural
pendulum swing.  I am not privy to the new Bergey's classification, so I do
not know just how inflated the final version has become.  We shall soon see.
     The fact that bacteriological diversity has been underappreciated and
understudied in the past does not justify swinging the pendulum too far in
the other direction.  I was a chemist and microbiologist before becoming a
mammalogist, so I think I have the background to see this issue from both a
microbiological and zoological perspective.
                      -----Ken Kinman
P.S.  To a lesser extent, Thomas Cavalier-Smith inflated the taxonomy of
protists in the same way.  He has already had to downgrade (and partially
dismantle) his former Kingdom Archezoa, and his Kingdom Chromista will
almost certainly suffer the same fate.  All of life on Earth can be
optimally divided into 4 or 5 kingdoms, and every attempt to increase the
number of Kingdoms will probably ultimately fail in the long run.
     I do not consider it old-fashioned to hold on to a good thing.  The
Kinman System is based on my belief that new knowledge can be incorporated
into classifications in  a way that avoids instability and confusion.  [no
time to proof read, so please forgive any typos].--K.E.K.
********************************************************
>From: "B. J. Tindall" <bti at DSMZ.DE>
>Reply-To: "B. J. Tindall" <bti at DSMZ.DE>
>To: TAXACOM at USOBI.ORG
>Subject: Prokaryota & Eukaryota; Lumpers & Splitters
>Date: Mon, 17 Apr 2000 09:04:03 +0200
>
>Ken Kinman wrote:
> >     But the concept of a primitive group of organisms
without nuclei seems
> >to have originated with Haeckel in the 19th Century
under the name Monera
> >(which is basically synonymous with Prokaryota).
>
>"Primitive" always sounds rather gradistic to me - next
time you read about
>the forward march of tuberculosis or the increase in
hospital infections
>you will realise that bacteria are very much "up-to-date".
They are only
>"primitive" in being unicellular. Even Haeckel put Monera
at the base of
>the tree and did not consider the group to represent
"crown taxa".
>
> >    This too continues to cause confusion, but nothing
compared to the
> >confusion the Woesian approach is causing in
bacteriology.  The current
> >taxonomic inflation (extreme splitting) which is now
apparent in
> >microbiology (apparently even the new Bergey's Manual,
which is
> >traditionally conservative) will eventually be followed
by a lumper's swing
> >back to a more intelligible and heuristic classification
of bacteria.  In
> >the meantime, I pity anyone (students, doctors,
clinicians, and biologists
> >in general) who has to try to wade through the mess
during the coming
> >decade.  The sad thing is that this kind of mess is
totally preventable and
> >senseless.
>
>Again I can't agree. I see no reason why we should not
recognise the
>diversity within "prokaryotes". The main reason for not
recognising the
>diversity at present seems to come from the fact that they
are not
>morphologically complex (c.f. Mayr). However, the
diversity is apparent at
>other levels. I am not basing my interpretation on 16S
rDNA data alone!
>Brian
>
>
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