Cladistics

Abstract

Cladistic methods aim to reconstruct the branching pattern of the Tree of Life. Cladistic classification is a philosophy of classification based only on cladistic relationships.

Keywords: evolution; phylogeny; cladogram; synapomorphy; homology

Figure 1.

Cladistic relationships among three Great Apes depicted in the form of a tree or cladogram. The cladogram represents the hypothesis that the last common ancestor of humans and chimpanzees was more recent than the last common ancestor of humans, chimpanzees and gorillas. Thus humans and chimpanzees are cladistically more closely related to each other than to gorillas.

Figure 2.

Incongruence between two simple characters, the presence or absence of halteres and of piercing mouths. For both characters absence is the plesiomorphic character state. As a potential synapomorphy, halteres provide evidence that the fruitfly and mosquito are more closely related to each other than either is to the aphid. This follows if halteres had a single origin in their common ancestor. As a potential synapomorphy, piercing mouths provide evidence that the mosquito and aphid are more closely related to each other than either is to the fruitfly. Both hypotheses of cladistic relationships cannot be true if there is only one true Tree of Life. Incongruence between the characters may be resolved either by more detailed study (which would reveal that the piecing mouthparts of mosquitoes and aphids are quite dissimilar and unlikely to be homologous) or through parsimony analysis in which other characters supporting the close relationship of the mosquito and fruitfly would outweigh the misleading and limited evidence provided by the superficial similarity in mouth parts.

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References

Farris JS (1983) The logical basis of phylogenetic inference. Advances in Cladistics 2: 1–36.

Hennig W (1966) Phylogenetic Systematics. Urbana, IL: University of Illinois Press.

Maddison WP, Donoghue MJ and Maddison DR (1984) Outgroup analysis and parsimony. Systematic Zoology 33: 83–103.

Swofford DL (1998) PAUP* 4.0. Sunderland, MA: Sinauer Associates.

Wilkinson M (1994) Common cladistic information and its consensus representation: reduced Adams and reduced cladistic consensus trees and profiles. Systematic Biology 43: 343–368.

Further Reading

Kitching IJ, Forey PL, Humphries CJ and Williams DM (1998) Cladistics, 2nd edn. Oxford: Oxford University Press.

Patterson C (1982) Morphological characters and homology. In: Joysey KA and Friday AE (eds) Problems in Phylogenetic Reconstruction. London: Academic Press.

Swofford DL, Olsen GJ, Waddell PJ and Hillis DM (1996) Phylogenetic inference. In: Hillis DM, Moritz C and Mable BK (eds) Molecular Systematics. Sunderland, MA: Sinauer Associates.

de Quieroz K and Gauthier JA (1992) Phylogenetic taxonomy. Annual Review of Ecology and Systematics 23: 449–480.

Wiley EO (1981) Phylogenetics: The Theory and Practice of Phylogenetic Systematics. New York: Wiley Interscience.

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How to Cite close
Wilkinson, Mark(Jun 2001) Cladistics. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1038/npg.els.0001522]