[Taxacom] Biodiversity questions: Classifications

Richard Jensen rjensen at saintmarys.edu
Fri Oct 4 07:24:45 CDT 2013


Chris,

While consistent (do you mean precise?) measure are used in much of
science, good science does not require such measures.  Many sources of
data, which lend themselves nicely to valid statistical evaluation, are
based on qualitative measures.

If you require that taxonomy needs a consistent degree of morphological,
ecological, behavioral, or genetic divergence for each taxonomic rank, then
you will be disappointed.  While this is, perhaps, a legitimate goal, I'm
not convinced it is workable across the tree of life.

Cheers,

Dick J


On Thu, Oct 3, 2013 at 10:12 PM, Chris Thompson <xelaalex at cox.net> wrote:

> Sorry, Ken,
>
> Yes, your proposal is fine, but is not Science.
>
> Yes, you can say some families are the same, and that other families are
> not the same as they may be equal to subfamilies or superfamilies. Some
> subfamilies are the same but others are equal to superfamilies or families.
> Et cetera.
>
> Science needs consistent measures. A meter or an ounce need to be the same
> across all hypotheses. Likewise, if one wants to make scientific hypotheses
> about biodiversity the groups need to be the same, representing a measure
> of the same underlying component, etc.
>
> Oh, well ...
>
> Chris
>
>
> From: Ken Kinman
> Sent: Thursday, October 03, 2013 5:48 PM
> To: Chris Thompson ; muscapaul ; taxacom at mailman.nhm.ku.edu
> Subject: RE: [Taxacom] Biodiversity questions: Classifications
>
> Hi Chris,
>
>        I hope Paul will respond to your post, as I thought it was an
> excellent point that needs to be answered and discussed more thoroughly and
> directly.
>
>        As far as higher classifications having no information bearing on
> biodiversity, I can think of one solution to that supposed problem.
>  Although the clades being compared should be roughly the same age, there
> is no reason that those clades need to be the same rank.  Family Hominidae
> (sensu stricto) could be compared to the subfamilies of Family Pongidae.
>  And your older dipteran family could be compared to Superfamily Carnoidea
> or an even more inclusive clade.  There are solutions that are less drastic
> than adopting Hennig's age of origin criterion, and perhaps that is why
> Hennig's proposed criterion has been ignored for decades.
>
>              -----------------Ken
>
>
> --------------------------------------------------------------------------------------------------------
>
>
> > From: xelaalex at cox.net
> > To: muscapaul at gmail.com; taxacom at mailman.nhm.ku.edu
> > Date: Thu, 3 Oct 2013 11:15:30 -0400
> > Subject: Re: [Taxacom] Biodiversity questions: Classifications
> >
> > PAUL:
> >
> > The scientific question that we begin with was about biodiversity.
> >
> > And Hennig said to answer those kinds of questions, then groups based on
> > time are the best.
> >
> > So, under the Hennig system, one could say that family X which now
> contains
> > 999 species is more biodiversity, has more speciation, etc., than family
> Z
> > which now contains only 1 species. BECAUSE the contents (species) of each
> > family represents a clade that has evolved over the SAME time period.
> >
> > But as I indicated in my Diptera example, comparison of the number of
> > species in Limoniidae versus Inbiomyiidae does not tell you anything
> about
> > biodiversity, speciation, etc. because those groups are not equivalent,
> not
> > comparable, etc.
> >
> > Oh, well ...
> >
> > Sincerely,
> >
> > Chris
> >
> > -----Original Message-----
> > From: muscapaul
> > Sent: Thursday, October 03, 2013 10:27 AM
> > To: TAXACOM
> > Subject: Re: [Taxacom] Biodiversity questions: Classifications
> >
> > Just out of interest: If actual age would (should?) be playing a role,
> > where do we then account for differences between taxa with highly
> divergent
> > generation time, like drosophilids with perhaps more than 10 generations
> > per year under favourable conditions and panthophthalmids which probably
> > take multiple years to develop? And then I am just considering taxa
> within
> > the same order where one might give rise to new taxa on a much shorter
> > absolute time scale than the other.
> >
> > Paul
> >
> > On 3 October 2013 12:59, Chris Thompson <xelaalex at cox.net> wrote:
> >
> > > So, for example, in Diptera, we now recognize a family which is a
> clade of
> > > some 10 thousand species and of some 200 million years old (Limoniidae)
> > > and
> > > another family of less than a dozen species and probably less than 5
> > > million
> > > years old (Inbiomyiidae).
> >
> > ...
> > >
> > > So, if one wants to derived scientific hypotheses from classifications,
> > > one
> > > must go back to clades and their age.
> > >
> > > Sincerely,
> > >
> > > Chris
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> Celebrating 26 years of Taxacom in 2013.
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-- 
Richard Jensen, Professor
Department of Biology
Saint Mary's College
Notre Dame, IN 46556



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