[Tcs-lc] Concepts of Higher Taxa

[Nico Franz]

Hi Roger:

   I think I've read through all posts regarding this issue. Briefly, 
Rich is correct in pointing out that depending on the definition based 
on membership vs. diagnostic properties, one might have less or more 
flexibility rearranging or reusing parent/child elements in succeeding 
classifications. For high-quality data, we also discussed the option of 
allowing subsequent reuse of "willfully (by the TCS) disconnected" 
parent- or child-concepts ("atomic concepts" - everything but children), 
so that other authors may use them even though the original author 
defined them partly through their connections. What if I found a new 
chimpanzee species today that fits 100% the diagnosis of the genus Pan 
(is that it?) given by Jones in 1980 - that kind of situation. My 
thinking is that in actual practice, people doing revisions will 
frequently reuse some but not all of an existing classification. The 
authors of the moss dataset decided to "seal off" their focal section of 
taxonomy (genus- and species-concepts for Germany) with nominal concepts 
on top (I think ordinal level, family could have worked too). One could 
do the same at the bottom (nominal species concepts in a genus-level 
concept revision). So I think in general, this is tricky business but 
also interesting and by no means a gloomy prospect. If concepts are 
stuck in their respective classifications there always the relationship 
assertions to build a narrow bridge.

Nico

Roger Hyam wrote:

>
> I have just noticed a big gap in my understanding of the concept of 
> taxon concepts and I was wondering what other peoples take on it was.
>
> My understanding of the circumscription of a genus is biased towards 
> the species that are included within it and less so on its description 
> and I think this is pretty common. As we go up the hierarchy taxa are 
> defined more by their members than by anything else. An author's 
> definition of a family is usually more or less just a list of genera 
> arranged into intermediate taxa of some kind.
>
> How is this handled in the Taxon Concept world? If we allow a GUID to 
> be created for a definition of genus G1 according to A1 and then some 
> one comes along and creates new species level taxon S1 according to A2 
> and says that it has a 'contained in' relationship with G1 according 
> to A1 does that alter G1 according to A1 concept?
>
> If so should we automatically create a G1 according to A2 concept and 
> circumscribe it as being the same as G1 according to A1 (a contains 
> relationship) but with the addition of S1?
>
> If we do this then the same logic surely applies all the way up the 
> chain to the kingdom level or does it stop at one level up? The same 
> arguments perhaps apply below species level with people adjusting 
> subspecies definitions.
>
> If we do allow changes in lower taxa to effect upper taxa then we are 
> into concept proliferation territory. If we don't then we are not 
> reflecting the way people really define taxa. Perhaps we should be 
> just thinking of taxa becoming more 'nominal' the higher up the chain 
> we go if not we get a new Plantae for every micro species of Rubus 
> that is created.
>
> In short: How do changes to contained taxon concepts affect the 
> concepts that hold them?
>
> Should we perhaps be talking more in terms of classifications (i.e. 
> trees of concepts) rather than billiard ball like concepts? An 
> according to actually freezes a tree of objects not a single object.
>
>_______________________________________________
>Tcs-lc mailing list
>Tcs-lc at ecoinformatics.org
>http://mercury.nceas.ucsb.edu/ecoinformatics/mailman/listinfo/tcs-lc
>  
>