Also referred to as the biological species concept, the isolation species concept, the species concept, and the species taxa.
Most often associated with Ernst Mayr (1904- ), an evolutionary biologist at Harvard University (but many other biologists have theorized on the subject before and since).
This is the idea that animals and plants can be considered groups of interbreeding natural populations that are reproductively isolated from other such groups.
While the definition of species may appear obvious to a layperson, biologists and philosophers continue to debate its parameters. Some suggest that the wide variety of species concepts being advocated by biologists and philosophers merely proves that there is no unique factor common to all species, and that the idea itself should be abandoned.
Also see: ALLOPATRIC SPECIATION, COHESION SPECIES CONCEPT, EFFECT HYPOTHESIS, GENETIC REVOLUTION, PARAPATRIC SPECIATION, RECOGNITION CONCEPT OF SPECIES, SALTATION SPECIATION, theory of speciation, species essentialism, SYMPATRIC SPECIATION
M Ereshefsky, The Units of Evolution: Essays on the Nature of Species (Cambridge, Mass., 1992)