[Taxacom] Biodiversity questions: Classifications

[Ken Kinman]

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

 

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> 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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