The purpose of this chapter is to help students understand how modern phylogenetic systematics (i.e., the classification based on evolutionary history) is based on cladistics analysis. This activity also gives students an opportunity to create a cladogram, which is a diagram that depicts a hypothetical branching sequence of lineages leading to specific species or genera. This activity also helps students learn how to engage in practices such as developing and using models, constructing explanations, arguing from evidence, and communicating information.