2. The Water Cycle, Carbon Dioxide/Oxygen Cycle, and Nitrogen Cycle Unit C, Chapter 1 Lesson 2 Pgs C14-C19

3. Earth’s Resources Earth’s ecosystems depend on energy from the sun. Ecosystems depend on other abiotic factors such as water, soil and gases. These things are in limited supply so why don’t we run out?

4. Earth’s Resources Abiotic materials can be used over and over because they move in a cycle. There are many natural cycles including The water cycle, carbon dioxide-oxygen cycle, and nitrogen cycle.

5. The Water Cycle The Water Cycle is the movement of water through Earth’s ecosystems. Most of Earth’s water is found in the oceans. It is also found in lakes, ponds, rivers and streams. All living things need water.

6. The Water Cycle “Evaporation” The water cycle is powered by the sun. Energy from the sun causes liquid water to change to a gas in a process called evaporation. Evaporation can also be caused by wind.

7. The Water Cycle “Condensation” When the water vapor (gas) cools down, it will condense. Condensation is the changing of a gas back to a liquid. When water vapor condenses on dust particles in the air it makes a cloud. This is why cold soda cans can “sweat.” Water vapor in the air is condensing on them.

8. The Water Cycle “Precipitation” When water droplets in clouds become large enough they fall back to earth as precipitation. Precipitation includes rain, snow, sleet, and hail. Animals consume the precipitation and return it to the earth as waste. The waste is then evaporated, returning the water to the air…this means you could be drinking old dinosaur pee….kind of.

9. The Water Cycle “Transpiration” Plants can return water to the air as well. This is called transpiration After they absorb water through the soil, they release it to the air using tiny pores called stomata. This helps photosynthesis and cools the plants.

10. The Water Cycle “Groundwater” Groundwater is water that has soaked into the ground…..duh. It includes water in the soil that plants use, or even underground rivers or lakes. Groundwater can become contaminated from pesticides, pollutants and fertilizers. Groundwater can be used up if it is pumped out faster than it can be replaced.

11. The Carbon Dioxide-Oxygen Cycle Living things depend on the gases carbon dioxide and oxygen. Plants use CO2 when they make their food. Animals and plants also use oxygen to release the energy in their food.

12. The Carbon Dioxide-Oxygen Cycle The Carbon Dioxide- Oxygen Cycle is the cycle of elements involved in photosynthesis and energy production. This cycle is also powered by the sun. Our air is about 21% oxygen and.04% carbon dioxide.

13. Photosynthesis During photosynthesis, plants make sugars by combining CO2 with water. While making these sugars, photosynthesis produces oxygen and some CO2 Plants use almost as much oxygen as they produce…so why don’t we run out? Tiny plant-like protists in the ocean called Phytoplankton produce much more oxygen then they use. They produce most of the earth’s oxygen.

14. The Nitrogen Cycle Living cells are made of proteins, one of the building blocks of proteins is nitrogen. Nitrogen makes up about 78% of our air. Most organisms can’t absorb nitrogen gas, it must be in compound form. Lightning changes nitrogen gas into compounds that plants can absorb.

15. The Nitrogen Cycle Animals get nitrogen from the plants they eat. Decomposers return nitrogen compounds to the soil from dead organisms. Some bacteria convert the compounds in soil back into gas for the atmosphere. Special plants called legumes (peanuts, peas, and beans) have bacteria that change nitrogen gas into compounds the plants use. Nitrogen compounds returning to the soil. Hey don’t blame me, the book shows a dead rabbit so I’m trying to be authentic.