Individuality, pluralism, and the phylogenetic species concept


Journal Article

The concept of individuality as applied to species, an important advance in the philosophy of evolutionary biology, is nevertheless in need of refinement. Four important subparts of this concept must be recognized: spatial boundaries, temporal boundaries, integration, and cohesion. Not all species necessarily meet all of these. Two very different types of "pluralism" have been advocated with respect to species, only one of which is satisfactory. An often unrecognized distinction between "grouping" and "ranking" components of any species concept is necessary. A phylogenetic species concept is advocated that uses a (monistic) grouping criterion of monophyly in a cladistic sense, and a (pluralistic) ranking criterion based on those causal processes that are most important in producing and maintaining lineages in a particular case. Such causal processes can include actual interbreeding, selective constraints, and developmental canalization. The widespread use of the "biological species concept" is flawed for two reasons: because of a failure to distinguish grouping from ranking criteria and because of an unwarranted emphasis on the importance of interbreeding as a universal causal factor controlling evolutionary diversification. The potential to interbreed is not in itself a process; it is instead a result of a diversity of processes which result in shared selective environments and common developmental programs. These types of processes act in both sexual and asexual organisms, thus the phylogenetic species concept can reflect an underlying unity that the biological species concept can not. © 1987 D. Reidel Publishing Company.

Full Text

Duke Authors

Cited Authors

  • Mishler, BD; Brandon, RN

Published Date

  • October 1, 1987

Published In

Volume / Issue

  • 2 / 4

Start / End Page

  • 397 - 414

Electronic International Standard Serial Number (EISSN)

  • 1572-8404

International Standard Serial Number (ISSN)

  • 0169-3867

Digital Object Identifier (DOI)

  • 10.1007/BF00127698

Citation Source

  • Scopus