Teaching population genetics provides a bridge between genetics and evolution by using examples of the mechanisms that underlie changes in allele frequencies over time. Existing methods of teaching these concepts often rely on computer simulations or hand calculations, which distract students from the material and are problematic for those with high math anxiety. We outline an exercise that engages students and provides real-time feedback through the use of classroom response devices. This exercise has been used with success and employs a conceptual-change approach to teach the fundamental, yet often misunderstood, concept of biological evolution.