1. Cycles in Nature
Chapter 1B

2. How Natural Materials are Reused
Lesson 1

3. Natural Cycles
Many materials are used and then reused by other organisms.
Some are stored on Earth for later use.
Examples:
Air stores large amounts of oxygen, nitrogen and carbon (carbon dioxide)
*Iron, copper, magnesium and calcium are stored in rocks.

4. The Nitrogen Cycle All living organisms need Nitrogen.
Plants get nitrogen from soil.
Animals get nitrogen from eating plants and other animals.
Main idea: Both plants and animals need nitrogen to make proteins.

5. Nitrogen Cycle continued…
Most organisms cannot use Nitrogen in its pure form from the atmosphere.
The nitrogen cycle gas is “fixed” (changed) so that plants can use it.
1. Nitrates
2. Ammonia

6. Nitrates vs. Ammonia Nitrates: Ammonia
Nitrates can be returned to the soil by animal waste.
*In other words.. An animal pooping helps the soil grow healthy protein filled plants!
Ammonia
Ammonia can be produced by liquid waste through animals.
*In other words.. An animal peeing helps the soil grow healthy protein filled plants!
Ammonia & Nitrates
When animals and plants die, the bacteria from the decaying bodies release nitrates and ammonia.

7. The Carbon- Oxygen Cycle
In the Carbon- Oxygen cycle, Carbon and Oxygen move among plants, animals and the environment. \
All life on Earth is involved in the cycle because carbon and oxygen make up most of the bodies in living organisms.
Two processes need to take place for this cycle: Photosynthesis and Respiration.

8. The Carbon- Oxygen Cycle
Photosynthesis: is how plant like organisms make their food.
Respiration: is the process that releases energy from food. During respiration, oxygen is taken from the air or water and carbon dioxide is released into the environment.

9. Changing the Balance
Since the beginning of the Industrial Revolution ( 200 years ago)- Human activity has changed the balance of the Carbon-Oxygen Cycle.
Carbon Dioxide has been omitted into the air, trees have been cut down, fuels have been burned and have polluted the air.

10. Changing the Balance
Excessive amounts of carbon dioxide in the air can be a problem.
Excess carbon dioxide can be poisonous to animals.
Since trees are being cut down, they are not able to take in the carbon dioxide.
As a result, carbon dioxide is still building up in the air.

11. Lesson Review
Most of the materials that organisms need will be cycled through nature.
Decaying organisms and animal waste place nitrates and ammonia back into the soil as part of the nitrogen cycle.
Plants and Animals need the exchange and cycle of oxygen and carbon to survive.

12. Why is the Water Cycle Important?
Lesson 2

13. The Water Cycle
Seas, oceans, lakes and rivers cover about 75% of the Earth’s surface.
The water in Earth’s environment moves through what is called – The Water Cycle.

14. Evaporation
Heat energy from the sun causes water in puddles, streams, rivers, seas or lakes to change from a liquid to a water vapor.
This is called evaporation.
The vapor rises into the air and collects in clouds.  

15. Condensation
Water vapor collects in clouds. As the clouds cool the water vapor condenses into water drops.
This is called condensation.
These drops fall to the earth as rain, snow or hail.

16. Precipitation
Water falls to the earth from clouds. Mainly as rain, but sometimes as snow and hail.
This is called precipitation.

17. Transpiration
Transpiration is the process by which plants lose water out of their leaves. 
Transpiration gives evaporation a bit of a hand in getting the water vapor back up into the air.

18. Condensation
The Clouds form
Transpiration
The movement through plants
Precipitation
The rain falls
Evaporation
The vapor rises

19. Humans & the Water Cycle
The amount of water on Earth today is almost the same as it was billions of years ago.
Some needs for water:
Drinking, bathing, cooking, waste removal, to grow crops, feed livestock and make materials.

20. Humans & the Water Cycle
Did you know…
Less than 1 percent of the Earths fresh water can be used because most of it is frozen in ice caps or glaciers.
People everywhere can conserve water by using washing machines and toilets that don’t need as much water.