This laboratory exercise introduces students to a fundamental tool in evolutionary biology--phylogenetic inference. Students are required to create a data set via observation and through mining preexisting data sets. These student data sets are then used to develop and compare competing hypotheses of vertebrate phylogeny. The exercise uses readily available resources and is flexible enough to be implemented for accomplishing a variety of educational objectives. In addition, this exercise requires students to critically evaluate hypotheses and to engage in decision-making processes using developing data sets. (Contains 3 figures.)