News from IAB

The mission of the International Association of Bryologists (IAB), as a society, is to strengthen bryology by encouraging interactions among all persons interested in byophytes.

Monday, November 10, 2008

Morphology, ecology, and classical taxonomic methodology

-------- Original Message --------
Subject: RE: BRYONET: Pottiaceae and new new classification
Date: Mon, 3 Nov 2008 08:38:36 +1100
From: Rod Seppelt <Rod.Seppelt@aad.gov.au>
To: 'bryonet-l@mtu.edu' <bryonet-l@mtu.edu>

BRYONET

I am moved to offer a comment following that made by Lars Hedenas (31 October).
The discussion on species, genera, families, evolutionary relationships, etc.,
has for the most part been written in terms that are specific to the realms of
the molecular geneticist and, I dare to add, largely incomprehensible to many
mere mortals (a group to which I align myself) - but, then, that is applying a
classification not only to myself but others and perhaps I should have assigned
myself a number - and a different number to each and everyone else!!
Molecular characteristics are just ONE of many characters we can use to classify
organisms. In the field, I do not use DNA sequences to identify what I am
looking at. I answer the innate call of the human species to classify or to
sort everything into some sort of order - to lump like with like, to make order
out of chaos.
To assign a number to every individual ignores, it seems to me, relationships,
notwithstanding the fact that Lars asserts that in Nature everything is more or
less part of a continuum.
As Nature deals in variation, Type species represent only one part of that
variation and perhaps in Botany we should take note of the standards applied by
Entomologists - at least 20 specimens of an insect are needed to draw up a
species description so that variation can be ascertained and described and also
the differences between male and female can be part of the morphological
description.
I walk my dog each morning accompanied by the Tasmanian Forensic Pathologist.
We have many and varied discussions and he confided to me the other morning that
DNA shows considerable variation - the result of random mutations. This makes
his job more difficult than it might be and emphasises the point that DNA is
not, perhaps, the definitive answer to everything.
Who knows if the species, let alone the individual assigned to a particular
species, in these molecular classifications is, in fact, a "good"
representative. If the Phylocode becomes the accepted norm, there will be great
scope for molecular biologists - they will need to sequence every single
individual in order to come up with a classification that indicates relationships.
Somewhat tongue in cheek, perhaps, but I intend to retain my faith in
morphology, ecology, and classical taxonomic methodology.

Prof. Rod Seppelt,
Principal Research Scientist,
Australian Antarctic Division,
Channel highway,
Kingston 7050,
Tasmania, Australia
ph: +61 (03) 6232 3438
FAX: +61 (03) 6232 3449
e-mail: rod.seppelt@aad.gov.au

---------------------------------------------------------------

4 comments:

  1. -------- Original Message --------
    Subject: RE: BRYONET: Pottiaceae and new new classification
    Date: Mon, 3 Nov 2008 14:12:03 -0800 (PST)
    From: MinJet Loo
    To: bryonet-l@mtu.edu

    BRYONET

    Dear Bryonet,

    Rod, great insight! We always tend to be so excitedly going into the
    molecular/DNA world without even solving the basic morphological dilemma. Due to
    government's research preference?

    Best wishes,
    J

    ReplyDelete
  2. -------- Original Message --------
    Subject: RE: BRYONET: Pottiaceae and new new classification
    Date: Tue, 04 Nov 2008 11:02:40 +0200
    From: Johannes Enroth

    BRYONET

    I find MinJet's comment a bit strange, if taken as a generalization.
    In the pleurocarpous moss family Neckeraceae, with which me and a
    group of colleagues are working (and shortly publishing several papers
    on) phylogenies based on nucleotide sequences in several genes have
    solved many "basic morphological dilemmas", including a large-scale
    homoplasy, some of which is clearly adaptive. Without the sequences,
    these dilemmas would have remained dilemmas for ever.
    Best regards,
    Johannes E.

    --
    Dr. Johannes Enroth
    PhD, University Lecturer, Bryologist
    Dept. of Biological and Environmental Sciences
    P.O. Box 65
    FIN-00014 University of Helsinki
    Finland
    ______

    ReplyDelete
  3. -------- Original Message --------
    Subject: RE: BRYONET: Pottiaceae and new new classification
    Date: Tue, 4 Nov 2008 16:04:36 -0600
    From: Richard Zander

    BRYONET

    "Large scale homoplasy," as discussed by Johannes Enroth can be
    explained in other ways than simple evolutionary convergence of
    expressed traits. I recommend my papers:

    http://www.mobot.org/plantscience/ResBot/Repr/Zander-Biodiversity8-2007.
    pdf
    or
    http://tinyurl.com/27fq62.

    and

    http://www.mobot.org/plantscience/ResBot/Repr/Proof_Zander_nonmonophyly.
    pdf
    or
    http://tinyurl.com/6hctpa

    Basically, given punctuated equilibrium and resulting stasis in some
    taxa, isolated populations of the same taxon may survive millions of
    years, giving off descendants. All lineages undergo DNA changes, but the
    original isolated populations remain morphologically static. Thus, both
    the molecular tree reflecting genetic continuity and isolation, and the
    morphological classification reflecting evolution of expressed traits
    are true.


    *****************************
    Richard H. Zander
    Voice: 314-577-0276
    Missouri Botanical Garden
    PO Box 299
    St. Louis, MO 63166-0299 USA
    richard.zander@mobot.org
    Web sites: http://www.mobot.org/plantscience/resbot/
    and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
    *****************************

    ReplyDelete
  4. -------- Original Message --------
    Subject: BRYONET: classification
    Date: 3 Nov 2008 03:32:52 -0000
    From: sunil kumar chaturvedi
    To: bryonet-l@mtu.edu

    BRYONET

    Bryonet,
    I too agree wih the views of Prof. Rod Sepplt regarding the
    Classification of taxa. The morphological,anatomical and ecological
    characters for a taxon are important as we can observe them in nature.
    However, Molecular sequencing may be one of the parameter for the
    critical species and varieties.


    S.K.Chaturvedi
    Department of Botany
    Nagaland University
    Lumami
    Mokokchung- 798 601
    Nagaland (India)

    ReplyDelete