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CYCLES IN NATURE

CYCLES IN NATURE. Section 1 – The Cycles of Matter. The movement of water between the oceans, atmosphere, land, and living things is known as the water cycle. water cycle link #1. water cycle link #2. water cycle link #3. water cycle link to on-line review game.

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CYCLES IN NATURE

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  1. CYCLES IN NATURE

  2. Section 1 – The Cycles of Matter The movement of water between the oceans, atmosphere, land, and living things is known as the water cycle.

  3. water cycle link #1 water cycle link #2 water cycle link #3 water cycle link to on-line review game

  4. During evaporation, the sun’s heat causes water to change from liquid to vapor. Evaporation link

  5. In the process of condensation, the water vapor cools and returns to a liquid state.

  6. The water that falls from the atmosphere to the land and ocean is precipitation. Rain, snow, sleet and hail are forms of precipitation.

  7. Most precipitation falls into the ocean. Some of the precipitation that falls on land flows into streams, rivers, and lakes and is runoff. Some precipitation seeps into the ground and is stored in spaces between or within rocks. This water, known as groundwater, will slowly flow back into the soil, streams, rivers, and oceans.

  8. Without water there would be no life on Earth. All organisms are made mostly of water. Water helps transport nutrients and wastes within organisms. Water also helps regulate temperature.

  9. Plants release a large amount of water vapor in a process called transpiration. transpiration link

  10. Besides water, the most common molecules in living things are organic molecules, or molecules that contain carbon. The exchange of carbon between the environment and living things is known as the carbon cycle.

  11. Photosynthesis is the basis of the carbon cycle.

  12. During photosynthesis, plants use carbon dioxide from the air to make sugars. Most animals get the carbon and energy they need by eating plants. It returns when sugar molecules are broken down to release energy. This process, called respiration, uses oxygen. Carbon dioxide and water are released as byproducts of respiration. photosynthesis link

  13. The breakdown of substances into simpler molecules is called decomposition.

  14. Combustion is the process of burning a substance, such as wood or fossils fuels. Like decomposition, combustion of organic matter releases carbon dioxide into the atmosphere.

  15. Nitrogen is also important to living things. Organisms need nitrogen to build proteins and DNA for new cells. The movement of nitrogen between the environment and living things is called the nitrogen cycle.

  16. About 78% of the Earth’s atmosphere is nitrogen gas. Most organisms cannot use nitrogen gas directly. Bacteria in the soil are able to change nitrogen gas into forms that plants can use. This process is called nitrogen fixation.

  17. Other organisms may the get the nitrogen they need by eating plants or eating organisms that eat plants.

  18. When organisms die, decomposers break down the remains. Decomposition releases a form of nitrogen into the soil that plants can use. Finally, certain types of bacteria in the soil convert nitrogen to a gas, which is returned to the atmosphere.

  19. Nitrogen Cycle

  20. Section 2 – EcologicalSuccession A gradual development of a community over time is called succession. Succession takes place in all communities.

  21. Sometimes, a small community starts to grow in an area where other organism had not previously lived. There is no soil in this area. Usually, there is just bare rock. Over a very long time, a series of organisms live and die on the rock. The rock is slowly transformed into soil. This process is called primary succession. The first organisms to live in an area are called pioneer species. See the visual concepts page on the Holt website: http://my.hrw.com

  22. Sometimes, an existing community is destroyed by a natural disaster, such as a fire or flood. Sometimes, a community is affected by another type of disturbance. For example, a farmer might stop growing crops in an area that has been cleared. When the original community regrows through a series of stages it is called secondary succession. See the visual concepts page on the Holt website: http://my.hrw.com

  23. As a community matures, it may be dominated by well-adapted, slow growing climax species. Western Red Cedar is what is known as a “climax” species. It will grow in virtually total shade and eventually take over the forest.

  24. The variety of species that are present in an area is referred to as biodiversity. Biodiversity is important to communities and organisms.

  25. Remember that a mature community may not always be a forest. A mature community simply has organisms that are well adapted to live together in the same area over time.

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