Fig. 2From: Using Inquiry and Tree-Thinking to “March Through the Animal Phyla”: Teaching Introductory Comparative Biology in an Evolutionary ContextGraphic illustrations used in an active learning exercise in lecture during which students evaluate alternative evolutionary hypotheses (adapted from Campbell and Reece 2002). a Trees I–III show different evolutionary relationships between four hypothetical species (A–D); b states for seven molecular characters for the four species. Tree I is marked with eight labeled horizontal lines that represent evolutionary changes in these seven characters (i.e., DNA base changes)Back to article page