Editing Apomorphy and synapomorphy (section)

== Clade analysis ==
The concept of synapomorphy depends on a given clade in the tree of life. [[Cladogram]]s are diagrams that depict evolutionary relationships within groups of taxa. These illustrations are accurate predictive device in modern genetics. They are usually depicted in either tree or ladder form. Synapomorphies then create evidence for historical relationships and their associated hierarchical structure. Evolutionarily, a synapomorphy is the marker for the most recent common ancestor of the monophyletic group consisting of a set of taxa in a cladogram.<ref>{{Cite journal |last=Novick |first=Laura R. |last2=Catley |first2=Kefyn M. |date=December 2007 |title=Understanding phylogenies in biology: the influence of a Gestalt Perceptual Principle |url=https://pubmed.ncbi.nlm.nih.gov/18194047 |journal=Journal of Experimental Psychology. Applied |volume=13 |issue=4 |pages=197–223 |doi=10.1037/1076-898X.13.4.197 |issn=1076-898X |pmid=18194047}}</ref> What counts as a synapomorphy for one clade may well be a primitive character or [[plesiomorphy]] at a less inclusive or nested clade. For example, the presence of [[mammary gland]]s is a synapomorphy for [[mammals]] in relation to [[tetrapod]]s but is a [[symplesiomorphy]] for mammals in relation to one another—rodents and primates, for example. So the concept can be understood as well in terms of "a character newer than" ([[autapomorphy]]) and "a character older than" ([[Plesiomorphy and symplesiomorphy|plesiomorphy]]) the apomorphy: mammary glands are evolutionarily newer than vertebral column, so mammary glands are an autapomorphy if vertebral column is an apomorphy, but if mammary glands are the [[apomorph]]y being considered then vertebral column is a plesiomorphy.