A probabilistic definition of a species, fuzzy boundaries and ‘sigma taxonomy’

Morphometric and genetic analyses of a variety of living and fossil taxa1- support the use of a probabilistic definition of a species in the context of ‘sigma taxonomy’ (where sigma represents ‘S’ for spectrum), in contrast to alpha taxonomy, for which boundaries discriminating species are presumed...

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Bibliographic Details
Published in:South African Journal of Science 2017-05, Vol.113 (5-6), p.24-25
Main Authors: Thackeray, J. Francis, Schrein, Caitlin M.
Format: Article
Language:English
Subjects:
Alpha taxonomy
Biological species constant
Boundaries
Chimpanzees
Classification
Evolution
Genetic analysis
Genetics
Genomes
Hominids
Hybridisation
Hybrids
Morphology
Morphometric analysis
Pan paniscus
Pan troglodytes
Population genetics
Populations
Probabilistic methods
Probability
Probability theory
Science
Studies
Taxonomy
Vocabularies & taxonomies
Zoology
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Summary:Morphometric and genetic analyses of a variety of living and fossil taxa1- support the use of a probabilistic definition of a species in the context of ‘sigma taxonomy’ (where sigma represents ‘S’ for spectrum), in contrast to alpha taxonomy, for which boundaries discriminating species are presumed to be distinct, thus accommodating only rigid, ‘either-or’ classification schemes. Recently, integrated taxonomic approaches, involving morphology and genetics, have demonstrated that traditional definitions of species boundaries may require re-evaluation and revision. Integrated analyses of gibbons and giraffes, for example, have narrowed boundaries and led researchers to recognise more species than were previously identified. Species identification is complicated in part by the potential for some populations to hybridise and, in the case of living wolf populations, genetic analyses have widened boundaries and revealed that there are fewer species – or more hybrids – than previously thought. Analyses of ancient DNA have also exposed hybrids of the past: there is now evidence that populations of elephants and mammoths likely interbred and, of course, Neanderthal DNA is known to be part of the modern human genome to this day, as a result of introgression of Neanderthals and early modern Homo sapiens – a relationship hinted at by morphology, now confirmed genetically.
ISSN:0038-2353
1996-7489
DOI:10.17159/sajs.2017/a0206