1. The Atmosphere in Balance

2. The Development of Earth’s Atmosphere
4.6 billion years ago
During it’s formation Earth was bombarded by many meteorites and collisions creating a lot of heat and gases
Earth had no oceans it was so hot all of the water was in the atmosphere
As Earth cooled it formed the lithosphere

3. The Development of Earth’s Atmosphere
Early Atmosphere
4.0 to 3.3 billion years ago
Volcanic activity released gases forming the early atmosphere
H2O, CO2, and N2 dominant.
SO2 and CH4 also present
Cooling of the atmosphere causes precipitation and the development of the oceans
By 3.0 billion years ago O2 begins to accumulate.

4. The Development of Earth’s Atmosphere
Oxygen:
First:
oxygen was probably produced by the splitting of water in the atmosphere
Later:
the development of blue-green algae created O2 as a byproduct of photosynthesis
**As life continued to develop the atmosphere continued to change

5. The Development of Earth’s Atmosphere
Living Atmosphere
3.3 billion years to Present
N2:78%,
O2: 21%,
Argon: 0.9%
CO2: 0.036%
OtherGases: (CH4, He, H, Kr, Ne)
H2O: Varies

6. Today’s Atmosphere 3.3 billion years to Present N2:78%, O2: 21%,
** Create a vertical bar graph (on the bottom of the front page… next to your percentages) to illustrate the principle gases found in dry air.
3.3 billion years to Present
N2:78%,
O2: 21%,
Argon: 0.9%
CO2: 0.036%

7. The Delicate Balance
The recycling of nutrients helps to keep the atmosphere stable
Important compounds and elements move between the atmosphere, biosphere, geosphere and hydrosphere keeping the balance
These are called biogeochemical cycles
Ex.
The Carbon/Oxygen Cycle
The Carbon Cycle
The Nitrogen Cycle

8. The Delicate Balance The Carbon/Oxygen Cycle (p367)
Plants/algae consume CO2 during photosynthesis and make O2
All living things consume O2 during respiration and make CO2
Draw a picture that illustrates this cycle:
How could this cycle go out of balance?

9. The Delicate Balance The Carbon Cycle (p15)
Carbon is stored in many ways moving between spheres through different processes
Hydrosphere
Atmosphere
Biosphere Geosphere
What do humans do to shift this cycle out of balance?
What natural occurrences could shift this cycle out of balance?

10. The Delicate Balance The Nitrogen Cycle
Nitrogen is an important element in protein
Atmosphere>>Bacteria>>Plants >> Animals >> Bacteria >> Atmosphere

11. What do humans do to shift this cycle out of balance?
What natural occurrences could shift this cycle out of balance?

12. The 4 spheres keep the delicate balance