[Taxacom] Biodiversity and paraphyly

[Richard Zander]

A Reuters article recently reported:
 
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Genetics Reveal 15 New North American Bird Species

February 19, 2007 - By Alister Doyle, Reuters 
 
OSLO -- Genetic tests of North American birds show what may be 15 new
species including ravens and owls -- look alikes that do not interbreed
and have wrongly had the same name for centuries, scientists said on
Sunday. 

If the findings from a study of birds' DNA genetic "barcodes" in the
United States and Canada hold true around the world, there might be more
than 1,000 new species of birds on top of 10,000 identified so far, they
said. 

A parallel study of South American bats in Guyana also showed six new
species among 87 surveyed, hinting that human studies of the defining
characteristics of species may have been too superficial to tell almost
identical types apart. 

"This is the leading tip of a process that will see the genetic
registration of life on the planet," said Paul Hebert of the
Biodiversity Institute of Ontario, a co-author of the report in the
British Journal Molecular Ecology Notes. 

"You can't protect biodiversity if you can't recognize it." 
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This is total nonsense. Surviving ancestors continue to accumulate
neutral genes yet retain essential identity (phenotype and niche . . .
remember niche?). Insisting on paraphyly in a molecular tree forces the
splitting of species into populations (nuclear genes) or even
individuals (mitochondrial and chloroplast genes), all of which may then
be termed "cryptic species" and named as new species (or genera or
families). This is what comes of abandoning the "modification" in
"descent with modification."
 
If a phylogenetically complex (isolated populations) species were to pup
a new species (different phenotype and niche) from somewhere central,
the sister group would have to be named a species, and a bunch of the
branches lower in the tree must also. The patristic distance, measured
as numbers of neutral base changes in DNA, between two end members among
the populations of the species could (and probably would) be greater
than the patristic distance between the new species and the nearest
population of the ancestral species. When doing biodiversity triage,
would one choose to protect the two end members of the original species
(same phenotype and niche) because they are "genetically distant"
(through neutral mutations) and let the new species go? Or, better,
recognize the adaptation and fitness of the phenome in a particular
environment as more important for biodiversity than the neutrally
evolving genome?
 
Biodiversity investigated with molecular analysis alone is rendered a
mere game by excessive atomization due to focus on neutral evolution and
forced monophyly. Eventually, with enough exemplars and exploration of
fan-shaped pedigree charts (matrilineally inherited traits), all
individuals will be named, or perhaps we can just stop with the
panmictic deme in those cases when lack of resolution from mitochondria
and chloroplasts requires studying recombining traits from nuclear
genes.
 
I foresee a paradigm shift back to biosystematics and the Modern
Synthesis. Molecular analysis does not protect biodiversity. Taxonomic
recognition of a unique phenotype interacting with a particular range of
environmental variables with a particular reproductive system, in
combination, does.
 
 
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Richard H. Zander 
Voice: 314-577-0276
Missouri Botanical Garden
PO Box 299
St. Louis, MO 63166-0299 USA
richard.zander at mobot.org
Web sites: http://www.mobot.org/plantscience/resbot/
and http://www.mobot.org/plantscience/bfna/bfnamenu.htm
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