1. The Biosphere and Atmosphere
Chapter 3
Lesson 3

2. The Atmosphere
Earth is surrounded by a mixture of gases: nitrogen, oxygen, carbon dioxides, water vapor.
The atmosphere changes constantly as gases are added and removed.
Examples:
a. As animals breath they remove oxygen and then add carbon dioxide
b. Plants remove carbon dioxide and add oxygen
c. Volcanic eruptions

3. Atmospheric Composition
78% is nitrogen
21% is oxygen
The other 1% is made up of gases like argon, carbon dioxide, methane, and water vapor

4. Besides gases, the atmosphere contains solid particles called “atmospheric dust”
Soil, salt, ash from fires, volcanic ash, matter from combustion (burning), skin, hair, clothing, pollen, bacteria and viruses

5. The Biosphere
Life on earth is restricted to a narrow layer around the Earth’s surface
Everything that organisms need to survive can be found within the “Biosphere”
“If Earth was an apple, the skin would be the biosphere”

6. What is the Biosphere? Where life exists
It extends from the ocean floor to the summit of the highest mountains. (about 18,000 km)
Includes all living organisms on earth, together with the dead organic matter produced by them
Has evolved since the first single-celled organisms originated 3.5 billion years ago

7. Closed System - energy can be exchanged but not matter
Open System - both energy and matter can be exchanged
B2 Where Science Lives

8. The Earth is a CLOSED system (NO matter is exchanged)
The Earth is a CLOSED system (NO matter is exchanged). However, Energy is constantly being exchanged.

9. How does matter move through the biosphere?
Matter is recycled within and between ecosystems.
Elements pass from one organism to another and among parts of the biosphere through closed loops called biogeochemical cycles, which are powered by the flow of energy.

10. How does human activity affect these processes?
On a global scale:
Mining and burning of fossil fuels
clearing of land for building and farming
burning of forests
the manufacture and use of fertilizers