1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Bellwork What is the difference between a renewable resource and a nonrenewable resource? Chapter 21

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Pollution Chapter 21 An unwanted change in the environment caused by substances, such as wastes, or forms of energy, such as radiation, is called pollution. Anything that causes pollution is called a pollutant. Some pollutants are produced by natural events, such as volcanic eruptions. Many pollutants are human-made. Pollutants may harm plants, animals, and humans.

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Chapter 21 1. Garbage The average Americans throw away more trash than the average person in any other nation –– about 12 kg of trash a week. This trash often goes to a landfill. Landfills often contain medical waste, lead paint, and other hazardous wastes. Hazardous waste includes wastes that can catch fire, eat through metal, explode, or make people sick.

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Chapter 21 2. Chemicals People need and use many chemicals. The same chemicals that help people may harm the environment. 3. High-Powered Wastes Nuclear power plants provide electricity to many homes and businesses. The plants also produce radioactive wastes. 4. Gases Since the Industrial Revolution, the amount of carbon dioxide in the atmosphere has increased, trapping heat around the Earth.

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Chapter 21 5. Noise Some pollutants affect the senses. These pollutants include loud noises. Noise pollution affects your ability to hear and think clearly, and it may damage your hearing.

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Chapter 21 Some of Earth’s resources are renewable, but other resources are nonrenewable. A renewable resource is one that can be replaced at the same rate at which the resource is used. A nonrenewable resource is one that cannot be replaced or that can be replaced only over thousands or millions of years. These resources will become more expensive as they become harder to find.

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Chapter 21 Renewable or Nonrenewable? Scientists used to think that fresh water was a renewable resource. However, in some areas, water supplies are being used faster than they are being replaced. Scientists are working on ways to keep these water supplies from being used up.

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Exotic Species Chapter 21 People may carry plant seeds, animals eggs, or adult organisms with them as they move from one part of the world to another. An organism that makes a home for itself in a new place outside its native home is an exotic species. Exotic species often thrive in new places, and can become pests and compete with native species.

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Human Population Growth Overpopulation happens when the number of individuals becomes so large that the individuals can’t get the resources they need to survive. Some people argue that there may eventually be too many people on Earth. Chapter 21

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 1 Environmental Problems Habitat Destruction When land is cleared for construction, crops, mines, or lumber, organisms that were living in the areas may be left without food and shelter. These organisms may die. An organism’s habitat is where it lives. Every habitat has a number and variety of organisms, or biodiversity. If a habitat is damaged or destroyed, biodiversity is lost. Chapter 21

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Forest Habitats Trees provide humans with oxygen, lumber, food, rubber, and paper. For some of these products, trees must be cut down. Deforestation is the clearing of forest lands. Marine Habitats Many people think of oil spills when they think of pollution in marine habitats. Spilled oil pollutes both open waters and coastal habitats. In addition to oil, chemicals and plastics are sometimes dumped into marine habitats. Section 1 Environmental Problems Chapter 21

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Effects on Humans Pollution and habitat destruction also affect humans. Sometimes, the effect is immediate, Sometimes, the damage is not apparent right away. Anything that harms other organisms may eventually harm people, too. Caring for the environment means being aware of what is happening now and looking ahead to the future. Section 1 Environmental Problems Chapter 21

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Environmental Solutions Bellwork Imagine that you have just finished reading a magazine. Write down at least two things you can do with the magazine that would be preferable to throwing it in the trash. Chapter 21

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Conservation One way to care for the Earth is conservation. Conservation is the preservation and wise use of natural resources. Conservation helps reduce waste and pollution. Conservation can help prevent habitat destruction. The three Rs describe three ways to conserve resources: Reduce, Reuse, and Recycle. Section 2 Environmental Solutions Chapter 21

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Environmental Solutions Chapter 21

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3 R’s 1. Reduce Reducing Waste and Pollution As much as one- third of the waste produced by some countries is packaging material. Products can be wrapped in less paper and plastic to reduce waste. Reducing the Use of Nonrenewable Resources Some scientists are looking for sources of energy that can replace fossil fuels. In some parts of the world, solar energy can be used to power homes. Section 2 Environmental Solutions Chapter 21

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 2. Reuse Reusing Products You might be surprised at how many materials can be reused. For example, every time you reuse a plastic bag, one bag fewer needs to be made. Reusing Water One way to reclaim water is to use organisms to clean the water. These organisms include plants and filter-feeding animals, such as clams. Section 2 Environmental Solutions Chapter 21

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 3. Recycle The recovery of valuable or useful materials from waste or scrap is called recycling. Recycling Trash Plastics, paper, aluminum, wood, glass, and cardboard are examples of materials that can be recycled. Recycling Resources Waste that can be burned can also be used to generate electricity. Electricity is generated in waste-to-energy plants. Section 2 Environmental Solutions Chapter 21

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Maintaining Biodiversity Protecting Species One way to maintain biodiversity is to protect individual species. In the United States, a law called the Endangered Species Act was designed to do just that. Protecting Habitats Each organism is part of a huge, interconnected web of organisms. The entire web should be protected to protect these organisms. Section 2 Environmental Solutions Chapter 21

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Environmental Strategies 1.Reduce pollution. 2. Reduce and pesticide use. 3. Protect habitats. 4. Learn about local issues. 5. Develop alternative energy sources. Section 2 Environmental Solutions Chapter 21

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu What You Can Do Reduce, reuse, and recycle. Protect the Earth. These are jobs for everyone. Children as well as adults can help clean up the Earth. The following slide offers some suggestions for how you can help. Section 2 Environmental Solutions Chapter 21

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Section 2 Environmental Solutions Chapter 21