Case studies are valuable tools for instruction but are often limited to a single topic and a single class period. Courses such as evolution that synthesize multiple concepts around a common theme, however, can use a single case study type project that extends over the entire semester to develop and link core concepts. A central theme in evolutionary biology is determining if complex biological traits represent adaptations that arose by natural selection. The instructional model presented here engages students in a step-by-step process to answer this question of adaptation for a trait of their choosing. In this process, the instructor first introduces the major concepts required to address adaptation. As each major concept is developed in class, students apply this concept to their particular trait, using information gathered from published studies. Students then report their research back to the class. At the end of the semester, each group synthesizes their evidence into a paper developing an argument as to whether or not their trait fits the criteria of being an adaptation. This project provides students with ownership of course material, gets students to act as practicing scientists, and helps them integrate and apply theoretical material to real questions.