Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

- A trait is understood to refer to any structure, function or behavior that occurs in various species in at least two different forms. From an evolutionary standpoint, the individual forms of a certain traits are not equivalent; one of them, the plesiomorphic form, for short plesiomorphy, is evolutionarily older in the particular phylogenetic line and the other forms were formed secondarily all at once or in a certain order as a consequence of anagenetic changes in the original form of the trait. These evolutionarily derived forms are termed apomorphic forms, abbreviated apomorphies.