Efforts to integrate mathematics and science have been widely recognized by mathematics and science educators. However, successful integration of these two important school disciplines remains a challenge. In this article, a mathematics and science activity extends the use of Venn diagrams to a life science context and then circles back to a discussion of professional development and classroom results. The activity presented seeks to integrate mathematics and science by engaging students in a meaningful exploration of both fields of study. In particular, this integration enables students to use mathematical diagrams to represent relationships involving topics in ecology, physiology, and life science.