This study explored how some college students understand the nature of the theory of evolution and how they evaluate its scientific status. We conducted semistructured interviews with 15 college biology seniors in which we asked them to explain why they think evolution assumes the status of a scientific theory, how it compares to other scientific theories, and what criteria do they use to determine if an explanation is scientific or not. Students' responses encompassed five themes that include evidence, certainty, experimentation, method of theory generation, and prediction. Those themes focused on the theory's empirical dimension which seemed to be derived from a generic and simplistic model of physical science theories that valued direct evidence. Demanding that evolutionary theory conform to this model reveals a misunderstanding of its "nature". This misunderstanding was expressed in relation to aspects of methodology, explanation, and prediction. The findings underscore the need for using explicit discipline- and context-specific approaches to teaching and learning about scientific theories.