[Taxacom] On genera, splitting and ranking

Scott Thomson scott.thomson321 at gmail.com
Sat Jul 13 12:16:55 CDT 2013


I also am of the opinion that age is a problematic part of the equation,
its assumptions as pointed out by Kim are some of the issues with it. I
think it also assumes that evolution is constant, and is constant for all
members of a clade. However I am not so sure that what we currently do is
"perfectly fine" but it is what we have for now. As Frank pointed out that
is no reason to not present our hypothesis, but it probably will change, we
have to accept that.

One of my other concerns is circularity in the arguments, It would be good
if the methods for defining a genus, were not intrinsically linked to the
methods for determining a species. Not sure where to go with that one right
now though I admit.

I think that the species concepts have been through a major overhaul over
the last few decades, and I can see that that was necessary before higher
orders were tackled. Maybe its coming a time to have a look at the higher
orders in the light of more modern methods for defining species.

Cheers, Scott


On Sat, Jul 13, 2013 at 1:05 PM, Kim van der Linde <kim at kimvdlinde.com>wrote:

> I think age is a useless criterion, because it assumes two things:
>
> 1. Age == evolution
> 2. Same age == same number of generations
>
> Obviously, a shorter generation time implies more generations and thus
> more genetic change. Evolution and change depends not only in the number
> of generations, but also on the need to adapt to novel situations,
> bottlenecks, and a load of other mechanisms that affect the realized
> change.
>
> I think that what we are doing now is mostly perfectly fine.
>
> Kim
>
>
> On 7/13/2013 10:38 AM, Frank.Krell at dmns.org wrote:
> > "Yes, Hennig once did propose a testable criterion for rank, that is,
> age of origin. However, everyone, including Hennig himself, rejected that
> criterion."
> >
> > Chris, would you remind me where he did so? I just cannot remember that
> he did, but it is long ago that I read all his theoretical works (in
> German).
> >
> > "Age is a wonderful and scientific criterion for rank. If we had such,
> then we could easily propose that higher Diptera (Cyclorrhapha, a suborder)
> is the same as birds (Aves, a Class) and far more diverse [Yes, the little
> creatures with narrow specialization generate more species, than larger
> more generalized predators, etc.]. But these kinds of scientific questions
> are not now possible due to the distorted system of classification we have
> and used."
> >
> > Isn't it amazing that a clear and useful criterion, probably the only
> phylogenetically justifiable criterion to define rank meets with so much
> resistance, rendering comparisons beyond one's small research domain so
> difficult?
> > Tradition (Aves is a class, Scarabaeidae is a family) is so much more
> important for emotionally heavily invested scientists than scientific
> reasoning.
> >
> > And, of course, we have many paraphyletic species, but we should not
> have paraphyletic higher taxa. There is no reason to let the pendulum swing
> back to pre-hennigian times.
> >
> > 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.
> > _______________________________________________
> > Taxacom Mailing List
> > Taxacom at mailman.nhm.ku.edu
> > http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
> >
> > The Taxacom Archive back to 1992 may be searched with either of these
> methods:
> >
> > (1) by visiting http://taxacom.markmail.org
> >
> > (2) a Google search specified as:  site:
> mailman.nhm.ku.edu/pipermail/taxacom  your search terms here
> >
> > Celebrating 26 years of Taxacom in 2013.
> >
>
>
> _______________________________________________
> Taxacom Mailing List
> Taxacom at mailman.nhm.ku.edu
> http://mailman.nhm.ku.edu/mailman/listinfo/taxacom
>
> The Taxacom Archive back to 1992 may be searched with either of these
> methods:
>
> (1) by visiting http://taxacom.markmail.org
>
> (2) a Google search specified as:  site:
> mailman.nhm.ku.edu/pipermail/taxacom  your search terms here
>
> Celebrating 26 years of Taxacom in 2013.
>



-- 
Scott Thomson
29400 Rt 6
Youngsville, PA, 16371
USA
(814) 230 1151
cell - (814) 779 8457
Skype: Faendalimas
http://www.carettochelys.com



More information about the Taxacom mailing list