Re: Species [arbitrary to a degree]

["Jaime A. Headden" <qilongia@yahoo.com>]

Randy King (randyk@ims.com) wrote:

<Doesn't the same problem (ring species) occur in evolution.  That would seem 
to be a critical
problem when you identify species with only a vague idea of where in time they 
belong.  As an
animal evolves through time you get an extreme case of the species problem.  
Its been addressed in
that context, with no resolution to my knowledge.

I'm not sure I see the relvance of the argument below, regarding a ring species 
as two distinct
species.  Maybe I'm missing something.  But the problem that I see is that you 
require a fuzzy
line to separate the species.  The ring species could be regarded as a single 
species or multiple
depending on the context, this makes it difficult to use the term with any 
relevance.  I think I'm
falling into the camp that the species concept isn't useful as its defined.>

  Same here. The operational use of the "species" may be as defunct as the 
"genus," but there are
two approaches to this "dumping" of either term: 1) one can regard them only as 
operational
constructs to reflect degrees of development (ranks) and simply discard both of 
them as useless,
and be left with simple organisms; or 2) you can note that no "species" is 
truly distinct from
it's sister species, i.e., forms a paraphyletic bundling before branching so 
that unless the
organism is so very distinctive that it may have had a long evolutionary 
isolation, there may be
no true "species" ... and just discard either concept. One is left with simple 
organisms and
populations. One can extend this to taxonomy: in neontology, we can have 
genetically distinct
populations of organisms; in paleontology, we can have morphologically distinct 
organisms _or_
populations. As it is, not matter how fine the fuzzy line gets, it's still 
fuzzy, and any sharp
line will be arbitrary. Now I side with the neontologists in saying that a 
fuzzy line a speciation
event does not make. Yet genetically distinct organisms exist still. Some are 
distinct enough even
from their fossil neighbors, like gorillas. Others genetically (like hoatzins) 
which have no
apparent sister group and have a great deal of morphological and genetic 
distance from their
comparative relatives, simply appear to indicate missing data from the fossil 
record.

  Such that speciation and species are not the same (apparently) it seems a 
good idea to ignore
the nature of the rank and the idea that a species may represent this genetic 
isolation. In the
consideration that organisms may have a complex morphological variation within 
their population,
even occuring as distinct morphologies (dog breeds and human races come to 
mind), which are not in
any sense "species" or even "subspecies," the species concept bound by 
morphology (not just
genetics) must be made on a case-by-case basis. I think it rams the idea home 
that a species
concept may very well need to be abandoned, and taxonomy follow a more 
arbitrary basis, as in
consideration of morphology in paleontology, or genetic uniqueness in 
neontology.

  Speaking for himself, one who's not partial to either side of the issue but 
just writes it as he
sees the possibilities of things,


=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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