The Biosphere
Ecosystems and Communities
Populations
Humans in the Biosphere
Matter and Energy
Interdependence in Nature
“Earth is a living planet on which all forms of life are linked to one another, and to land, water, and air. Through those links, energy flows and matter cycles in patterns that support life, including human society. We know enough about these patterns to realize that they are changing, due to human activity, in ways that we don't understand. Our challenge is to study our impact on the biosphere and plan for a healthy future.”