Abstract
The correct explanation of why species, in evolutionary theory, are individuals and not classes is the cladistic species concept. The cladistic species concept defines species as the group of organisms between two speciation events, or between one speciation event and one extinction event, or (for living species) that are descended from a speciation event. It is a theoretical concept, and therefore has the virtue of distinguishing clearly the theoretical nature of species from the practical criteria by which species may be recognized at any one time. Ecological or biological (reproductive) criteria may help in the practical recognition of species. Ecological and biological species concepts are also needed to explain why cladistic species exist as distinct lineages, and to explain what exactly takes place during a speciation event. The ecological and biological species concepts work only as sub-theories of the cladistic species concept and if taken by themselves independently of cladism they are liable to blunder. The biological species concept neither provides a better explanation of species indivudualism than the ecological species concept, nor, taken by itself, can the biological species concept even be reconciled with species individualism. Taking the individuality of species seriously requires subordinating the biological, to the cladistic, species concept.
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References
Cracraft, J.: 1987, ‘Species concepts and the ontology of evolution’, Biology and philosophy 2, 329–346.
Ehrlich, P. R. & P. H. Raven: 1969, ‘Differentiation of populations’, Science 165, 1228–1232.
Ghiselin, M. T.: 1966, ‘On psychologism in the logic of taxonomic controversies’, Systematic zoology 15, 207–215.
Ghiselin, M. T.: 1974, ‘A radical solution to the species problem’, Systematic zoology 23, 536–544.
Ghiselin, M. T.: 1987, ‘Species concepts, individuality, and objectivity’, Biology and philosophy 2, 127–143.
Hennig, W.: 1966, Phylogenetic systematics, University of Illinois Press, Urbana.
Hull, D. L.: 1965, ‘The effect of essentialism on taxonomy’, British journal for the philosophy of science 15, 314–326; 16, 1–18.
Hull, D. L.: 1978, ‘A matter of individuality’, Philosophy of science 45, 335–360.
Hull, D. L.: 1987, ‘Genealogical actors in ecological roles’, Biology and philosophy 2, 168–184.
Johnson, L. A. S.: 1970, ‘Rainbow's end: the quest for on optimal taxonomy’, Systematic zoology 19, 203–239.
Maynard Smith, J.: 1986, The problems of biology, Oxford University Press, Oxford.
Mayr, E.: 1963, Animal species and evolution, Oxford University Press, London.
Mayr, E.: 1987, ‘The ontological status of species: scientific progress and philosophical terminology’, Biology and philosophy 2, 145–166.
Mishler, B. D. & R. N. Brandon: 1987, ‘Individuality, pluralism, and the phylogenetic species concept’, Biology and philosophy 2, 397–414.
Nelson, G. & N. I. Platnick: 1981, Systematics and biogeography, Columbia University Press, New York.
Paterson, H. E. H.: 1978, ‘More evidence against speciation by reinforcement’, South African journal of science 74, 369–371.
Paterson, H. E. H.: 1985, ‘The recognition concept of species’. In E. S. Vrba (ed.), Species and speciation. Transvaal Museum Monograph, no. 4, Transvaal Museuum, Pretoria, p. 21–29.
Ridley, M.: 1986, Evolution and classification: the reformation of cladism, Longman, London.
Rosenberg, A.: 1985, The structure of biological science, Cambridge University Press, Cambridge.
Rosenberg, A.: 1987, ‘Why does the nature of species matter? Comments on Ghiselin and Mayr’, Biology and philosophy 2, 192–197.
Simpson, G. G.: 1953, The major features of evolution, Columbia University Press, New York.
Van Valen, L.: 1971, ‘Adaptive zones and the orders of mammals’, Evolution 25, 420–428.
Van Valen, L.: 1976, ‘Ecological species, multispecies, and oaks’, Taxon, 25, 233–239.
Wiley, E. O.: 1978, ‘The evolutionary species concept reconsidered’, Systematic zoology 27, 17–26.