This interrupted case study focuses on the research of Dr. Beatrice Hahn, who investigates DNA sequences in chimpanzee droppings in order to explore the origins of the human immunodeficiency virus (HIV). Students first consider the types of data that can be gained through collecting chimpanzee feces and studying the behavior of these animals. Students then apply this information to learn more about microevolution when they compare DNA sequences. Finally, students learn about ELISA tests and consider the role of basic and applied science. This case study is appropriate for an introductory biology course for non-majors or majors.

In this case study, students speculate on what may have caused a major fish kill in an estuary in North Carolina. In the process, they explore how land runoff and excess nutrients affect aquatic communities, and learn about the complex life cycle of the dinoflagellate Pfiesteria. The case is appropriate for an introductory environmental science course, a general biology course that covers ecology, or a general zoology course.