bio

Apomorphy

A new, derived character state - a novelty a lineage introduced, differing from the ancestral condition. The apomorphy is what matters in building a family tree, because a shared novelty reveals a common ancestor that produced it. When an apomorphy is carried by two or more species it is a synapomorphy; when only one species carries it, it is an autapomorphy. Its opposite is the ancestral state, the plesiomorphy.