Practical Considerations

Bad taxonomy can kill.

• Daugherty, C., A. Cree, J.M. Hay and M.B. Thompson. 1990. Neglected taxonomy and continued extinctions in Tuatura. Nature 347: 177-178.

Comaparability of entities.

Concepts often in use.

Typological
Phenetic Generalized
Biological

Specific Criteria Bases (Linneaus,  Rollins, Campbell, Roberty etc.)

PSC I (Donoghue, Mishler, deQuieroz, Brandon)
"The minimum monophyletic unit"
 
 

• Mishler, B. and R. Brandon 1987. Individuality. pluralism, and the phylogenetic species concept. Biology and Philosophy 2:397-414.
• Baum, D. and M.J. Donoghue.  1995.  Choosing among alternative “phylogenetic” species concepts.  Systematic Botany 20: 560-573.
• deQueiroz, K. and M. Donoghue 1988. Phylogenetic Systematics and the species problem. Cladistics 4: 317-338.
• Donoghue, M. 1985. Acritique of the biological species concept and recommendations for a phylogenetic alternative. Bryologist 88: 172-181.
•  Mishler, B.D.  1985.  The morphological, developmental and phylogenetic basis of species concepts in bryophytes.  Bryologist 88: 207-214.
• Baum, D. and M.J. Donoghue.  1995.  Choosing among alternative “phylogenetic” species concepts.  Systematic Botany 20: 560-573.

PSC II (Wheeler, Nixon & Davis)
"The smallest non-arbitrary units supported by unique combinations of char4acter states"
 

• Davis, J.I. and K.C. Nixon.  1992.  Populations, genetic variation, and the delimitation of phylogenetic species.  Systematic Biology 41: 421-435.
• Nixon, K.C. and Q.D. Wheeler.  1990.  An amplification of the phylogenetic species concept.  Cladistics 6: 211-223.
• Davis, J.I.  1993.  Species concepts and the progress of systematics. (Abstract).  American Journal of Botany 80 (6, suppl.): 117.

Class vs. Individual

Grouping vs. Ranking

Metaspecies

Formal vs. Informal recognition.