Editing Cladogram (section)

===Homoplasies===

A [[homoplasy]] is a character state that is shared by two or more taxa due to some cause ''other'' than common ancestry.<ref>{{cite book |last=West-Eberhard|first=Mary Jane| author-link=Mary Jane West-Eberhard | title=Developmental Plasticity and Evolution |url=https://archive.org/details/developmentalpla00west|url-access=limited|pages=[https://archive.org/details/developmentalpla00west/page/n373 353]–376| year=2003 |publisher=Oxford Univ. Press | isbn=978-0-19-512235-0 }}</ref> The two main types of homoplasy are convergence (evolution of the "same" character in at least two distinct lineages) and reversion (the return to an ancestral character state). Characters that are obviously homoplastic, such as white fur in different lineages of Arctic mammals, should not be included as a character in a phylogenetic analysis as they do not contribute anything to our understanding of relationships.  However, homoplasy is often not evident from inspection of the character itself (as in DNA sequence, for example), and is then detected by its incongruence (unparsimonious distribution) on a most-parsimonious cladogram.  Note that characters that are homoplastic may still contain [[phylogenetic signal]].<ref>{{cite journal|doi=10.1111/j.1096-0031.1999.tb00400.x|title=Homoplasy Increases Phylogenetic Structure|journal=Cladistics|volume=15|pages=91–93|year=1999|last1=Kalersjo|first1=Mari|last2=Albert|first2=Victor A.|last3=Farris|first3=James S.|s2cid=85905559}}</ref>

A well-known example of homoplasy due to convergent evolution would be the character, "presence of wings". Although the wings of birds, [[bat]]s, and insects serve the same function, each evolved independently, as can be seen by their [[anatomy]]. If a bird, bat, and a winged insect were scored for the character, "presence of wings", a homoplasy would be introduced into the dataset, and this could potentially confound the analysis, possibly resulting in a false hypothesis of relationships.  Of course, the only reason a homoplasy is recognizable in the first place is because there are other characters that imply a pattern of relationships that reveal its homoplastic distribution.