The authors used a case study-based approach in the introductory biology course at Spelman College. The course taught to entering freshmen was divided into three modules--ecology, evolution, and biodiversity, each designed around a case study. They noted that (1) case study teaching was dramatically more effective than the traditional lecture method, (2) students preferred cases dealing with human health, and (3) weaker students showed greater enthusiasm for the case method than stronger students. (Contains 3 tables.)