To make the concept of biomes fresh for high school students and help them achieve more conceptual depth, the author Amy Slack created the "Who's in the Zoo?" project. Working in groups, students design a zoo that represents five of Earth's biomes and the climate found in their respective habitats. These groups prepare a proposal and a poster of their zoo design that they present to the class. The 5E learning cycle--engage, explore, explain, elaborate, and evaluate--provides the framework for this project (Trowbridge, Bybee, and Powell 2004), which takes six one-hour class periods to complete. (Contains 2 figures.)