[Taxacom] Biodiversity questions: Classifications
Fred Schueler
bckcdb at istar.ca
Thu Oct 3 11:08:33 CDT 2013
On 10/3/2013 11:54 AM, John Grehan wrote:
>
>
> On Fri, Oct 4, 2013 at 4:51 AM, John Grehan <calabar.john at gmail.com
> <mailto:calabar.john at gmail.com>> wrote:
>
> But we do not have published ages, only published miminal ages.
* but the minimal age of an ancestoral divergence is a maximum age for
the divergence of descendents.
Categories are a hierarchical sequence, and since time is linear, it's a
lot less ambiguous than "expert opinion" as a tie-down for the
hierarchy. The much more complex alternative would be to measure the
pheneticists' "overall morphological similarity" as a surrogate for
ecological divergence, and assign levels of phenetic difference to each
category.
fred.
========================================================
>
> 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 -
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> > on the Smiths Falls Limestone Plain 44* 52'N 75* 42'W
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> <bckcdb at istar.ca <http://istar.ca>
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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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> The Taxacom Archive back to 1992 may be searched with either of
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>
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>
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> site:mailman.nhm.ku.edu/pipermail/taxacom
> <http://mailman.nhm.ku.edu/pipermail/taxacom> your search terms
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> Celebrating 26 years of Taxacom in 2013.
>
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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 <bckcdb at istar.ca> http://pinicola.ca/
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