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Why Can’t We Build a Biosphere?

Kathy Gallucci
Biology Department
Elon University


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.


  • Describe the initial purpose and scope of the Biosphere 2 project.
  • Compare Biosphere 1 and Biosphere 2.
  • Define ecosystem services and categorize examples as supporting, provisioning, regulating, or cultural in Biosphere 1 and Biosphere 2.
  • Describe an ecological footprint and the ecosystem services impacted by modern lifestyles.
  • Interpret their personal "ecological footprint," and compare it to the biocapacity of Earth.
  • Compare our collective ecological footprint with Earth's biocapacity.


sustainability; ecosystem services; ecological footprint; Biosphere 2; biosphere; biocapacity; Earth; nutrient cycling; supporting services; regulating services; provisioning services; cultural services; Arizona; Oracle;

Educational Level

Undergraduate lower division


PDF, PowerPoint

Type Methods

Discussion, Flipped, Interrupted



Subject Headings

Biology (General) Ecology Environmental Science

Date Posted


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The following video(s) are recommended for use in association with this case study.

  • Jane Poynter: Life in Biosphere 2
    This video is a personal account of one of the original biospherians who lived in Biosphere 2 for “two years and twenty minutes.” Ms. Poynter describes the facility, the goals of the project, the challenges and crises encountered during her stay, personal reflections, and applications of the project to present day environmental thinking. Running time: 15:53 min. Produced by TED Talks, 2009.
  • Inside Biosphere 2, The World’s Largest Earth Science Experiment
    This video surveys the current uses of Biosphere 2, including its function as a public museum. The video also describes the largest earth science experiment ever conducted, LEO (“Landscape Evolution Observatory”), and the history of the two human experiments in Biosphere 2. Running time: 16:55 min. Produced by The Good Stuff (PBS), 2015.
  • Have You Thanked Your Ecosystem Today?
    This video provides information students need to identify and classify four types of ecosystem services, as identified by The Millennium Ecosystem Assessment (2009). Its purpose is to assess ecosystem change and assess its impact on human wellbeing. Running time: 6:52 min. Created by Kathy Gallucci for the National Center for Case Study Teaching in Science, 2017.