Methods for inferring evolutionary trees and their applications to the fields of comparative biology, molecular evolution, and systematics. Topics to be covered include phylogenetic inference, molecular evolution integrated at the organismal and population level, and evolutionary developmental genetics. Labs emphasize practical experience in data analysis. Prerequisite: BIOL 335 or consent of instructor. BIOL 380 or 392 recommended. Credit cannot be obtained for both BIOL 421 and BIOL 521. Offered in alternate years.