title: Tempo and mode in evolution.
authors.affiliation: Department of Ecology and Evolutionary Biology, University of California, Irvine 92717.
authors.forename: W M
authors.initials: WM
authors.lastname: Fitch
authors.forename: F J
authors.initials: FJ
authors.lastname: Ayala
mesh_terms: D000818:Animals; D005075:Biological Evolution; D006801:Humans; D000069497:Origin of Life; D012641:Selection, Genetic