1. Unit D: Energy Flow in Global Systems

2. The Biosphere

3. Biosphere: the thin layer of air, land, and water on or near Earth’s surface that contains all life on Earth Atmosphere (air): is a mixture of nitrogen, oxygen and other gases that extends 800km above the Earth’s surface – Is concentrated in the lower two layers: troposphere (0km - 12km) and the stratosphere (13km - 50km)

4. The Atmosphere

5. Lithosphere (land): is Earth’s crust that forms land above sea level and at the ocean bottom as well as the uppermost part of the Earth’s mantle. Varies in thickness from 100km to 200km.

6. The Lithosphere

7. Hydrosphere (water): is water on or near Earth’s surface. Includes water in oceans, rivers, lakes, streams and underground reservoirs, and in the atmosphere.

8. The Hydrosphere