Editing Systematics (section)

==Taxonomic characters==
Taxonomic characters are the taxonomic attributes that can be used to provide the evidence from which relationships (the [[phylogeny]]) between taxa  are inferred.<ref>Mayr, Ernst and Peter D. Ashlock (1991). Principles of Systematic Zoology, (2nd edn.) New York: McGraw-Hill, p. 159.</ref> Kinds of taxonomic characters include:<ref>Mayr, Ernst and Peter D. Ashlock (1991), p. 162.</ref>
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* Morphological characters
** General external morphology
** Special structures (e.g. genitalia)
** Internal morphology (anatomy)
** Embryology
** Karyology and other cytological factors
* Physiological characters
** Metabolic factors
** Body secretions
** Genic sterility factors
* Molecular characters
** Immunological distance
** Electrophoretic differences
** Amino acid sequences of proteins
** DNA hybridization
** DNA and RNA sequences
** Restriction endonuclease analyses
** Other molecular differences
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* Behavioral characters
** Courtship and other ethological isolating mechanisms
** Other behavior patterns
* Ecological characters
** Habit and habitats
** Food
** Seasonal variations
** Parasites and hosts
* Geographic characters
** General biogeographic distribution patterns
** Sympatric-allopatric relationship of populations
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