[Taxacom] Biodiversity questions: Classifications
David Campbell
pleuronaia at gmail.com
Thu Oct 3 16:47:33 CDT 2013
Besides age of origin, it would be possible to declare that all clades
originating at a certain level in a tree belong to a particular rank, or a
certain level of morphological or molecular divergence indicates a
particular rank, if one wants an objective rule for assigning a particular
rank. Probably additional criteria could be found as well. However, it's
also quite likely that any of these approaches will elevate certain groups
and demote others relative to what seems reasonable on other grounds.
Although it's not objective, the current system tends to integrate a sense
of degree of character divergence with depth of origin.
If the group in question has had a uniform standard of classification
applied to it, then the relative diversity in the various taxa tells us
something relative to that standard of classification. But comparing
families of bacteria and mammals is not very meaningful, for example.
On Thu, Oct 3, 2013 at 12:06 PM, <Frank.Krell at dmns.org> wrote:
> I strongly disagree.
> Are there ANY non-subjective alternatives to age-based categorization?
>
> Frank
>
>
> Dr. Frank-T. Krell
> Curator of Entomology
> Commissioner, International Commission on Zoological Nomenclature
> Chair, ICZN ZooBank Committee
> Department of Zoology
> Denver Museum of Nature & Science
> 2001 Colorado Boulevard
> Denver, CO 80205-5798 USA
> Frank.Krell at dmns.org
> Phone: (+1) (303) 370-8244
> Fax: (+1) (303) 331-6492
> http://www.dmns.org/science/museum-scientists/frank-krell
> lab page: http://www.dmns.org/krell-lab
>
> The Denver Museum of Nature & Science aspires to create a community of
> critical thinkers who understand the lessons of the past and act as
> responsible stewards of the future.
>
>
>
> From: John Grehan [mailto:calabar.john at gmail.com]
> Sent: Thursday, October 03, 2013 10:03 AM
> To: Frank T. Krell
> Cc: Fred Schueler; taxacom
> Subject: Re: [Taxacom] Biodiversity questions: Classifications
>
> The 'so what' is that phylogenetic age is not something that can be used
> at present in any scientifically informative way.
>
> John Grehan
>
> On Fri, Oct 4, 2013 at 4:58 AM, <Frank.Krell at dmns.org<mailto:
> Frank.Krell at dmns.org>> wrote:
> Yes, of course. So what? Science will always be an unfinished business. At
> least additional knowledge can be integrated in an age-based categorization.
> Are there ANY non-subjective alternatives to age-based categories?
>
> Yes, paraphyletic groups pose lots of problems. That's why we do not
> consider them in a phylogenetic system.
>
> Frank
>
>
> Dr. Frank-T. Krell
> Curator of Entomology
> Commissioner, International Commission on Zoological Nomenclature
> Chair, ICZN ZooBank Committee
> Department of Zoology
> Denver Museum of Nature & Science
> 2001 Colorado Boulevard
> Denver, CO 80205-5798 USA
> Frank.Krell at dmns.org<mailto:Frank.Krell at dmns.org>
> Phone: (+1) (303) 370-8244<tel:%28%2B1%29%20%28303%29%20370-8244>
> Fax: (+1) (303) 331-6492<tel:%28%2B1%29%20%28303%29%20331-6492>
> http://www.dmns.org/science/museum-scientists/frank-krell
> lab page: http://www.dmns.org/krell-lab
>
> The Denver Museum of Nature & Science aspires to create a community of
> critical thinkers who understand the lessons of the past and act as
> responsible stewards of the future.
>
>
>
>
> -----Original Message-----
> From: taxacom-bounces at mailman.nhm.ku.edu<mailto:
> taxacom-bounces at mailman.nhm.ku.edu> [mailto:
> taxacom-bounces at mailman.nhm.ku.edu<mailto:
> taxacom-bounces at mailman.nhm.ku.edu>] On Behalf Of John Grehan
> Sent: Thursday, October 03, 2013 9:52 AM
> To: Fred Schueler
> Cc: taxacom
> Subject: Re: [Taxacom] Biodiversity questions: Classifications
> But we do not have published ages, only published miminal ages.
>
> John grehan
>
>
> On Fri, Oct 4, 2013 at 4:35 AM, Fred Schueler <bckcdb at istar.ca<mailto:
> bckcdb at istar.ca>> wrote:
>
> > On 10/3/2013 11:20 AM, John Grehan wrote:
> > > Trouble is that there is no standard objective method for assigning
> > > age since all age estimates are minimal. Some have made some
> > > esoteric mathematical arguments for having confidence in a
> > > particular age or range, but its still an argument. Some groups may
> > > have some level of "consensus" or majority opinion, but its still
> > > just an opinion. As yet there is no unambiguous criterion for
> determining precise age.
> >
> > * sure - it's an hypothesis. As Bunge says "we know that all our
> > constructions are defective, hence corrigible." Ages associated with a
> > name both give the general user an idea of at least roughly how old a
> > group is thought to be, and would challenge specialists to improve the
> > resolution of their estimates.
> >
> > We now have enough published ages of groups that we can guess in the
> > ages of descendent groups, and challenge paleontology, biogeography,
> > and genetic comparisons to improve the accuracy of these guesses.
> > We've been guessing about distributions on the basis of collected
> > specimens for centuries, and this is the same procedure extended from
> > spatial to temporal estimates.
> >
> > fred.
> > =================================================
> > > On Fri, Oct 4, 2013 at 3:59 AM, Fred Schueler <bckcdb at istar.ca<mailto:
> bckcdb at istar.ca>
> > > <mailto:bckcdb at istar.ca<mailto:bckcdb at istar.ca>>> wrote:
> > >
> > > On 10/3/2013 6:59 AM, Chris Thompson wrote:
> > > > There is NO scientific information to be derived from higher
> > > classifications
> > > > as there are NO scientific principles / standards underlying our
> > > current
> > > > classifications.
> > > >
> > > > Willi Hennig years ago tried to suggest a standard (age of
> > > origin) on which
> > > > to base rank within a classification. BUT he was ignored by all.
> > >
> > > * others who have made the suggestion independently have also been
> > > ignored. If an age is associated with each category, then the
> > > use of
> > the
> > > category for a monophyletic group becomes a falsifiable
> > > hypothesis,
> > and
> > > rescues the notion of category from the stigma of Aristotelian
> > > arbitrariness.
> > >
> > > I wonder, if this isn't to be done in an immediate convulsion, if
> the
> > > proposed age of the group could be appended, along with the
> author's
> > > name - e.g. class Mammalia (L; early Permian) - until consensus
> > emerges
> > > on the ages of categories in each higher taxon, perhaps grading
> > > into
> > a
> > > system where age alone is the categorical marker.
> > >
> > > fred.
> > > ------------------------------------------------------------
> > > Frederick W. Schueler & Aleta Karstad
> > > Bishops Mills Natural History Centre -
> http://pinicola.ca/bmnhc.htm
> > > Mudpuppy Night in Oxford Mills - http://pinicola.ca/mudpup1.htm
> > > Daily Paintings - http://karstaddailypaintings.blogspot.com/
> > > RR#2 Bishops Mills, Ontario, Canada K0G 1T0
> > > on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
> > > (613)258-3107<tel:%28613%29258-3107> <tel:%28613%29258-3107>
> <bckcdb at istar.ca<http://istar.ca>
> > > <http://istar.ca>> http://pinicola.ca/
> > > ------------------------------------------------------------
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> > --
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> > Frederick W. Schueler & Aleta Karstad Bishops Mills Natural
> > History Centre - http://pinicola.ca/bmnhc.htm Mudpuppy Night in Oxford
> > Mills - http://pinicola.ca/mudpup1.htm Daily Paintings -
> > http://karstaddailypaintings.blogspot.com/
> > RR#2 Bishops Mills, Ontario, Canada K0G 1T0
> > on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
> > (613)258-3107<tel:%28613%29258-3107> <bckcdb at istar.ca<
> http://istar.ca>> http://pinicola.ca/
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--
Dr. David Campbell
Assistant Professor, Geology
Department of Natural Sciences
Gardner-Webb University
Boiling Springs NC 28017
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