Taxonomy and biology

Chris J. Durden drdn at
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
>  ------------------------------------------------------------
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