Abstract
This case study is designed to help students learn about the ecosystem services of Earth (Biosphere 1) by examining the challenges faced by the designers who tried to replicate its components in Biosphere 2. In 1991, four men and four women entered Biosphere 2, a man-made closed ecological system in Arizona, to see if eight biospherians could be sustained by this miniature version of Biosphere 1. The project succeeded in producing most of the food needed, but required additional oxygen before the end of the two-year experiment. After an introduction to Biosphere 2, students learn about the four main types of ecosystem services and discuss how Biosphere 2 might provide these services. At the end of the case, students calculate their own ecological footprint, demonstrating how humans are overreaching the ecosystem services of Biosphere 1, just as the biospherians could not be sustained by the ecosystem services included in Biosphere 2. The case is suitable for an introductory undergraduate course in biology, ecology, or environmental science.