Engaging students in a predator-prey simulation to teach natural selection is a common activity in secondary biology classrooms. The purpose of this article is to demonstrate how the authors have changed their approach to teaching this activity from a laboratory investigation to a class-constructed simulation. Specifically, the authors drew upon a research-based teaching tool (FAR guide) to help students understand how the simulation is analogous to what happens in nature. Teaching the activity in this way can help students connect the parts of the simulation to four basic components of natural selection.