Taxonomy and biology
Chris J. Durden
drdn at mail.utexas.edu
Sat Sep 8 02:50:41 EDT 2001
Sometimes I have the impression that the people with the strongest views on
what constitutes a species have little hands on experience with many groups
of species living together in the wild. I am thinking of a certain lush and
knobby forest in central Rondonia where more than 1,800 butterfly species
cavort in an area about 10 by 20 k. There each genus and species group
presents a different challenge. I am also thinking of my home territory in
Travis Co., Texas where more than 180 butterfly species cavort in a
slightly larger area. I am also thinking of Atkasook on Mead River where
nearly 18 species cavort in the millions.
The styles of interspecific interactions and within-species variation
are different under these three very different ecological regimens.
In the high latitude sample there appears to be much more variation
expressed within species, sometimes to the extent that one suspects
ecotypes or cryptic species are present. The common species are very common
and the rare species are very rare.
In the low latitude sample the common species are not as common as one
would suspect and the rare species are not as rare as one would expect.
There appears to be far less within-species variation than found normally
at higher latitudes. In the thousands of individuals examined there are
almost no extreme variants.
In the mid-latitude sample there is a tremendous amount of variation in
the populations of most species. Perhaps this is a reflection of recent
habitat disruption by changes in land use practises. In the thousands of
individuals examined there have been a number of extreme variants seen in
several species. Remarkably some of the tropical species that occur here in
fall show much more variation than do comparable samples from tropical
forest 500 miles to the south.
There do appear to be different styles of speciation in different
faunas. I interpret this as meaning that there are a number of different
ways for an interbreding population of genetic material to fit a niche. I
suggest that any species definition should be derived from the process that
selects what survives, rather than the mechanics of what is put into the
selective process.
As good field practice, the habitat should be described along with the
individuals of a species. Just as we build up a knowledge of what
constitutes an individual species, we can build up a knowledge of what
constitutes its niche.
I have found that finding what looks like a familiar species in a
different niche, is a red flag to look closer at the individual, which
often turns out to be a related but different species.
..............Chris Durden
At 10:07 AM 9/7/2001 -0700, you wrote:
>Something in the back of my feeble old mind crept to the front and caused me
>to reflect on taxonomy and nomenclature with the perhaps erroneous
>recollection that these noble tools were originally invented to facilitate
>communication among biologists (and everyone else with biological/natural
>history interests) and to facilitate the study of living organisms. I
>sometimes think these pursuits have taken on a life of their own and are
>pursued as an end onto themselves.
>Perhaps we need to remind ourselves of their "proper" place in the grand
>scheme of things. Sometimes it is indeed easy to lose sight of the forest
>because of all the trees :-) I wonder at times if the tail is wagging the
>dog :-) Blast away with impunity and gusto if you see it differently :-)
>
>~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>Norbert Kondla P.Biol., RPBio.
>Ministry of Sustainable Resource Management
>845 Columbia Avenue, Castlegar, British Columbia V1N 1H3
>Phone 250-365-8610
>Mailto:Norbert.Kondla at gems3.gov.bc.ca
>http://www.env.gov.bc.ca
>
>
>
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