1. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Bellwork 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. Chapter 19

2. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 The movement of water between the oceans, atmosphere, land, and living things is known as the water cycle. How Water Moves During evaporation, the sun’s heat causes water to change from liquid to vapor. In the process of condensation, the water vapor cools and returns to a liquid state. The Water Cycle

3. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 The water that falls from the atmosphere to the land and oceans is called precipitation. 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.

4. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 The Water Cycle

5. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 Water and Life Without 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.

6. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 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. The Carbon Cycle

7. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 Photosynthesis and Respiration During 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.

8. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 Decomposition and Combustions The breakdown of substances into simpler molecules is called decomposition. For example, when fungi and bacteria decompose organic matter, carbon dioxide and water are returned to the environment. Combustion is the process of burning a substance, such as wood or fossil fuels. Combustion of organic matter releases carbon.

9. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 The Carbon Cycle

10. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 Living things need nitrogen to build proteins and DNA. The movement of nitrogen between the environment and living things is called the nitrogen cycle. The Nitrogen Cycle

11. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 Converting Nitrogen Gas Although 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.

12. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 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.

13. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 The Nitrogen Cycle

14. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Cycles of Matter Chapter 19 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. Many Cycles

15. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Bellwork 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? Chapter 19

16. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19 Regrowth of a Forest Succession The replacement of one type of community by another at a single place over a period of time is called succession. 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.

17. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19 1. 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.

18. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19

19. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19 2. 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.

20. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19

21. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19 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.

22. ResourcesChapter menu Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 Ecological Succession Chapter 19 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.