Changes in Ecosystems

1. Changes in Ecosystems Chapter1 Lesson 5

2. Objectives Students will: • Explore factors that change ecosystems. • Discuss different types of pollution and how they harm ecosystems. • Discuss ways people can fight pollution.

3. What causes ecosystems to change? • A resource is a material that helps support life on Earth. • To survive within an ecosystem, organisms need many resources such as: • Water • Sunlight • Soil • Air

4. What causes ecosystems to change? • Some resources, such as water, can run out or dry up. • Others such as sunlight, never run out. • Sometimes events occur that cut off or destroy a resource. Ventura County, California

5. What causes ecosystems to change? • Drought: • A long period of time with little or no precipitation, such as rain. • During a drought, plants may turn brown and die. • When plants die, the consumers that need them for food can also die. • Animals also need water to drink. Lake Powell, Paige, AZ

6. Corn fields affected by a drought.

7. What causes ecosystems to change? • Diseases can harm an ecosystem. • Dutch elm disease (DED). • It is a fungus. • It affects the trees by blocking the vascular system and preventing the transport of water and nutrients to the leaves. • The leaves wilt and eventually the tree dies.

8. What causes ecosystems to change • In 1930 it arrived in N.A. in wood crates made of diseased elm wood. • Over time DED spread from tree to tree. • It killed more than half of all N.A. elm trees. • Between 1945 and 1976, 43 million trees died from DED. • Elm trees add to the oxygen we breathe. • They can also prevent soil erosion.

9. What causes ecosystems to change? • How does Elm disease spread? • European Elm bark-beetle. • Root contact between trees. • Humans transporting infected wood around (either with fungus or beetles in it).

10. What causes ecosystems to change? • DED harms more than just elm trees. • Trees are home to many insects and other animals. • When a tree dies, these animals homes are destroyed.

11. What causes ecosystems to change? • Fire can also change an ecosystem. • How would a fire in a rain forest affect the animals that live and feed on trees?

12. What causes ecosystems to change? • Overpopulation is another factor that changes ecosystems. • Overpopulation happens when an ecosystem has too many of at least one kind of living thing. • In many crowded cities, people have left little or no space for other animal to live.

13. What causes ecosystems to change? • Overpopulation reduces the resources that all living things must share. • In Australia, overpopulation of kangaroos has become a big problem.

14. What causes ecosystems to change? • Dingos • A wild dog that hunts kangaroo. • As the number of dingos decreased, the number of kangaroos increased. • Kangaroos compete with other livestock on farms for food and water. • They also knock down fences and cause erosions.

15. What causes ecosystems to change? • How has the Australian government dealt with this problem? • They have allowed a certain number of kangaroos to be hunted. • They are used for leather, pet food, and even human food.

16. How can people change ecosystems? • Pollution • It happens when harmful substances are added to Earth’s water, air, or land. • Humans and other living things need a clean place to live.

17. How can people change ecosystems? • Water Pollution • Waste from homes or factories are dumped into rivers, lakes, and oceans. • Water pollution is a problem for everyone. • It makes the water too dirty to use. • It can be dangerous. • Plants and animals that live in the polluted water can die. • Living things can get sick.

18. How can people change ecosystems? • Water Pollution • In 1989 the oil tanker Exxon Valdez ran aground in Alaska’s Prince William Sound. • It spilled 11 million gallons of oil. • The oil polluted the water and coastline for 600 miles from the ship. • Many animals became sick or died. • www.video.yahoo.com/video/play?vid=1091686304&fr=yfp-t-501

20. How can people change ecosystems? • Water Pollution • Between 300,000 and 675,000 animals were killed. • Sadly, pockets of oil can still be found in the water today. • This oil spill also harmed the people of Alaska. • In some villages people could no longer catch fish. • They lost their jobs and money. http://video.yahoo.com/video/play?vid=1094032167&fr=yfp-t-501

22. How can people change ecosystems? • Air Pollution • It can come from forest fires or volcanoes. • Most of it comes from cars and factories. • Burning gasoline, coal, and other fuels can pollute the air.

23. How can people change ecosystems? • Acid Rain • Burning gasoline, coal, and other fuels release compounds of sulfur and nitrogen called acids. • This acid mixed with water in the air then falls to the Earth as acid rain. • Acid rain can ruin our lakes, forests, soils, and crops. • Too much acid rain can harm many plants and animals.

24. How can people change ecosystems? • Smog • Waste gases and smoke from cars, homes, and factories may join with water in the air to form smog. • It hangs in the air like a cloud. • It can make the air harder to breathe. • It can sting the eyes. • Smog Alerts • People who have trouble breathing should say inside during a smog alert.

25. What the difference between fog and smog? Smog Fog • It is pollution. • Waste gases and smoke from cars, homes, and factories. • It is condensation. • It is created by warm water moist air moving over cold water.

26. How can people change ecosystems? • Land Pollution • Acid rain, chemical wastes, smog, and trash can also pollute our soil. • Soil or land that is polluted can harm the plants and animals that live on it. • It can also make everything look unattractive or ugly.

27. How can human fight pollution? • In order to keep ecosystems healthy, we must use resources wisely. • Using energy wisely can help keep our air clean. • Shut off televisions and radios when not in use. • Turn off lights in an empty room. • Ride a bus or train. • Carpool when possible.

28. How can human fight pollution? • The U.S. government has written laws to control air pollution. • Clean Air Act. • It sets limits on different kinds of air pollution. • The laws in California are stricter. • Cars sold here must meet tough tests that help keep pollution low.

29. How can human fight pollution? • Littering • We can help by: • Cleaning up litter when we see it. • Recycling and reusing. • Keeping the land clean helps everyone.

30. How can human fight pollution? • Water Pollution • It is a problem in thousands of lakes, rivers, and other bodies of ocean. • Clean Water Act • It tells states to clean polluted waters and to stop further pollution. • We can help by: • Not dumping waste that could harm our water. • Don’t throw things into rivers, lakes, or oceans.

31. Questions • A new factory opens in your area. Suddenly, dead fish are found in the local stream. • What can you infer? • How can you determine if your inference is correct?

32. Homework • Science Packet due tomorrow

33. Appointment Assignment • What types of things can you do everyday to help prevent harmful changes in the environment?

34. Experiment