In biological systematics, as well as in the philosophy of biology, species and higher taxa are individuated through their unique evolutionary origin. This is taken by some authors to mean that monophyly is a (relational) property not only of higher taxa, but also of species. A species is said to originate through speciation, and to go extinct when it splits into two daughter species (or through terminal extinction). Its unique evolutionary origin is said to bestow identity on a species through time and change, and to render species names rigid designators. Species names are thus believed to function just like names of supraspecific taxa. However, large parts of the Web of Life are composed of species that do not have a unique evolutionary origin from a single population, lineage or stem-species. Further, monophyly is an ambiguous concept if it is defined simply in terms of ‘unique evolutionary origin’. Disambiguating the concept by defining a monophyletic taxon as ‘a taxon that includes the ancestor and all, and only, its descendant’ renders monophyly inapplicable to species. At the heart of the problem lies a fundamental distinction between species and monophyletic taxa, where species form mutually exclusive reticulated systems, while higher taxa form inclusive hierarchical systems. Examples are given both at the species level and below to illustrate the problems that result from the application of the monophyly criterion to species. The conclusion is that the concepts of exclusivity and monophyly should be treated as non-overlapping: exclusivity marks out a species synchronistically, i.e. in the present time. Monophyly marks out clades (groups of species) diachronistically, i.e. within an historical dimension.
Keywords Phylogenetic systematics  monophyly  exclusivity  species
Categories (categorize this paper)
Edit this record
Mark as duplicate
Export citation
Find it on Scholar
Request removal from index
Revision history

Download options

PhilArchive copy

Upload a copy of this paper     Check publisher's policy     Papers currently archived: 57,077
External links

Setup an account with your affiliations in order to access resources via your University's proxy server
Configure custom proxy (use this if your affiliation does not provide a proxy)
Through your library

References found in this work BETA

No references found.

Add more references

Citations of this work BETA

No citations found.

Add more citations

Similar books and articles

Species, Higher Taxa, and the Units of Evolution.Marc Ereshefsky - 1991 - Philosophy of Science 58 (1):84-101.
Species Concepts Should Not Conflict with Evolutionary History, but Often Do.Joel D. Velasco - 2008 - Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences 39 (4):407-414.
Species Concepts and Species Delimitation.Kevin de Quieroz - 2007 - Systematic Biology 56 (6):879-886.
What is a Species, and What is Not?Ernst Mayr - 1996 - Philosophy of Science 63 (2):262-277.
Vague Kinds and Biological Nominalism.Peter Simons - 2013 - Metaphysica 14 (2):275-282.
The Cladistic Solution to the Species Problem.Mark Ridley - 1989 - Biology and Philosophy 4 (1):1-16.
A (Not-so-Radical) Solution to the Species Problem.Bradley E. Wilson - 1995 - Biology and Philosophy 10 (3):339-356.
Species Pluralism Does Not Imply Species Eliminativism.Ingo Brigandt - 2003 - Philosophy of Science 70 (5):1305–1316.


Added to PP index

Total views
11 ( #797,248 of 2,411,290 )

Recent downloads (6 months)
1 ( #538,938 of 2,411,290 )

How can I increase my downloads?


My notes