Cycles in Nature

1. Chapter 19 Cycles in Nature Preview Section 1The Cycles of Matter Section 2Ecological Succession Concept Mapping

2. Chapter 19 Section 1The Cycles of Matter Bellringer What are the three different physical states of water that are found on Earth? Name one way that you use water in each of these states in your daily life. Write your answers in your science journal.

3. Chapter 19 Section 1The Cycles of Matter Objectives • Diagram the water cycle, and explain its importance to living things. • Diagram the carbon cycle, and explain its importance to living things. • Diagram the nitrogen cycle, and explain its importance to living things.

4. Section 1The Cycles of Matter Chapter 19 The Water Cycle • The movement of water between the oceans, atmosphere, land, and living things is known as the water cycle. • How Water MovesDuringevaporation,the sun’s heat causes water to change from liquid to vapor. • In the process ofcondensation,the water vapor cools and returns to a liquid state.

5. Section 1The Cycles of Matter Chapter 19 The Water Cycle, continued • The water that falls from the atmosphere to the land and oceans is calledprecipitation. Rain, snow, sleet, and hail are all forms of precipitation. • Most precipitation falls into the ocean. • The precipitation that falls on the land and flows into streams, rivers, and lakes is called runoff. • Groundwater is precipitation that seeps into the ground and is stored between or within rocks. Groundwater slowly flows back into the soil, streams, rivers, and oceans.

6. Section 1The Cycles of Matter Chapter 19 The Water Cycle

7. Section 1The Cycles of Matter Chapter 19 The Water Cycle, continued • Water and LifeWithout water, there would be no life on Earth. All organisms, from bacteria to animals and plants, are composed mostly of water. • Water helps transport nutrients and waste within an organism. • Water helps regulate temperature. • All water taken in by an organism is eventually returned to the environment.

8. Section 1The Cycles of Matter Chapter 19 The Carbon Cycle • 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.

9. Section 1The Cycles of Matter Chapter 19 The Carbon Cycle, continued • Photosynthesis and RespirationDuring photosynthesis, plants use carbon dioxide from air to make sugars. • Most animals get the carbon and energy they need by eating plants. Plants and animals break down sugar molecules to release energy in a process called respiration. • Respiration uses oxygen and releases carbon dioxide and water back into the environment.

10. Section 1The Cycles of Matter Chapter 19 The Carbon Cycle, continued • Decomposition and CombustionsThe breakdown of substances into simpler molecules is calleddecomposition. • For example, when fungi and bacteria decompose organic matter, carbon dioxide and water are returned to the environment. • Combustionis the process of burning a substance, such as wood or fossil fuels. Combustion of organic matter releases carbon.

11. Section 1The Cycles of Matter Chapter 19 The Carbon Cycle

12. Section 1The Cycles of Matter Chapter 19 The Nitrogen Cycle • Living things need nitrogen to build proteins and DNA. • The movement of nitrogen between the environment and living things is called the nitrogen cycle.

13. Section 1The Cycles of Matter Chapter 19 The Nitrogen Cycle, continued • Converting Nitrogen GasAlthough 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. • Other organisms get the nitrogen they need by eating plants or animals that eat plants.

14. Section 1The Cycles of Matter Chapter 19 The Nitrogen Cycle, continued • Passing It On On When organisms die, decomposers break down the remains. • Decomposition releases a form of nitrogen into the soil that plants can use. • Certain types of bacteria in the soil convert nitrogen to a gas, which is returned to the atmosphere.

15. Section 1The Cycles of Matter Chapter 19 The Nitrogen Cycle

16. Section 1The Cycles of Matter Chapter 19 Many Cycles • Other forms of matter on Earth also pass through cycles. Many of the minerals that living cells need, such as calcium and phosphorous, are cycled through the environment. • Each of the cycles is connected in many ways. • Living organisms play a part in each of the cycles.

17. Chapter 19 Section 2Ecological Succession Bellringer • Imagine that you have been hired to oversee the maintenance of a public forest. Answer the following questions to describe how you would approach the task: • How would you evaluate the health of the forest? • What actions would you take to keep the forest healthy? • Record your answer in your science journal.

18. Chapter 19 Section 2Ecological Succession Objectives • Describe the process of succession. • Contrastprimary and secondary succession. • Explain how mature communities develop.

19. Chapter 19 Section 2Ecological Succession Regrowth of a Forest • SuccessionThe replacement of one type of community by another at a single place over a period of time is calledsuccession. • The regrowth of a forest after a forest fire is an example of succession. • Succession takes place in all communities, not just those affected by disturbances such as forest fires.

20. Chapter 19 Section 2Ecological Succession Primary Succession • Sometimes, a small community starts to grow in an area where other organisms had not previously lived. • 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.

21. Section 2Ecological Succession Chapter 19

22. Chapter 19 Section 2Ecological Succession Secondary Succession • Sometimes, a community is disturbed in some way. If soil is left intact, the original community may regrow through a series of stages called secondary succession.

23. Section 2Ecological Succession Chapter 19

24. Chapter 19 Section 2Ecological Succession Ecological Succession Click below to watch the Visual Concept. Visual Concept

25. Chapter 19 Section 2Ecological Succession Mature Communities and Biodiversity • In the early stages of succession, only a few species grow in an area. As a community matures, it may be dominated by a well-adapted, slow-growing climax species. • The variety of species that are present in an area is referred to as biodiversity. Having biodiversity helps communities lessen the impact and spread of disturbances such as insect invasions.

26. Chapter 19 Section 2Ecological Succession Mature Communities and Biodiversity, continued • Mature communities tend to have biodiversity. A mature community simply has organisms that are well adapted to live together in the same area over time.

27. Chapter 19 Cycles in Nature Concept Mapping Use the terms below to complete the Concept Mapping on the next slide.

28. Chapter 19 Cycles in Nature

29. Chapter 19 Cycles in Nature