While the concept of evolution by natural selection is very simple, it is often misunderstood by students. This is partly due to preconceptions they have as well as a lack of understanding or emphasis on the idea that reproductive success (and not survival) is what matters to evolution. One way to ensure that students grasp this concept is to confront them with situations that require them to examine each factor’s effect on survival and reproduction. In this case study, the evolution of human skin color is used as a means of exploring the process of evolution by natural selection. Through the progressive disclosure of data, students learn about the factors that may have exerted pressure on the evolution of this trait. Students evaluate hypotheses, predict their outcomes, evaluate them in light of new information, and reformulate them to take unexplained data into consideration. The case has been used in a first-year introductory biology course for non-majors.