1. Ch. 20 Sect 2
Cycles of Matter

2. How does matter move in ecosystems?
Law of Conservation of Mass -Water, carbon, oxygen, nitrogen and other types of matter continuously move through ecosystems.
Elements move through one matter cycle may play a role in another cycle. Ex. Oxygen’s role in the water cycle.

3. Water (H₂O) Cycle Water covers 70 % of Earth’s surface.
97% of water is in the oceans.
Water is also located in the atmosphere, glaciers, and living things.
Water Cycle – the movement of water between the Earth and its atmosphere.
3 processes: evaporation, condensation, and precipitation.

4. Water (H₂O) Cycle
1. Evaporation – the process of liquid water changing into a gas called water vapor. *Transpiration – the release of water vapor from the leaves and stems of plants. 2. Condensation – process during which water vapor changes into liquid water. 3. Precipitation – Water that falls from clouds to Earth’s surface.

6. Nitrogen (N₂) Cycle
The movement of Nitrogen from Earth and its atmosphere.
Is a necessary part of proteins, part of DNA
Atmosphere is mostly N₂
Nitrogen Fixation – the process that changes atmospheric nitrogen into nitrogen compounds that are usable by living things.
Bacteria breaks down N₂ from dead organisms and return it back to the environment.
Manure contains N₂ which is used for plant growth.

8. Oxygen (O₂) Cycle
Almost all living things need oxygen for cellular processes that release energy.
Oxygen is a part of water (H₂O) and carbon dioxide (C₂O).

9. Carbon (C₂) Cycle All organisms contain carbon.
It is a part of proteins, sugars, fats, and DNA.
Some get carbon from food, or bodies of water or the atmosphere.
Carbon can be found in the soil, air, and fossil fuels.
Greenhouse effect – carbon absorbs thermal energy from the Sun and keeps the Earth warm.