How Do Ecosystems Change?

Transcription

1 How Do Ecosystems Change? Lesson Focus Vocabulary: Science concepts: Reading skill focus: and. How ecosystems change Ecosystems the changes are. and s cause changes. They can and many living things.. that into. into the to the plants. ecosystems. When to build a dam, they change the forest. How Do Ecosystems Change? 1

2 Their the way the. Cause and effect: when beavers build a dam, what are the effects on the ecosystem? How people change ecosystems change ecosystems when they use the, or, from them. They to build houses. They up and stones to make. They use that animals and plants. of these the ecosystem. the air. rivers and fields. People also can ecosystems., and goes a long way. after ourselves after a develop a. Bringing water to dry areas helps more plants grow. How Do Ecosystems Change? 2

3 1.) 2.) 3.) 4.) 5.) Cause and effect How are the ecosystems affected by people? Make a list of 5 or more things that you threw into the trash today. Compare your list with the two people who sit next to you Together, decide what items could have been recycled. How Do Ecosystems Change? 3

4 Effects of changes in ecosystems When of an ecosystem changes, it can the. Changes such as cause some animals to, or and for the that are. If there are, populations get r. members, and some. If a change brings, populations. Some organisms are able to to changes in an ecosystem. live near than in the far away from people, why do you think that is? People build homes in the habitats of bears, deer, and other animals. What does this do to animals? Cause and effect: What happens to organisms when an ecosystem changes? How Do Ecosystems Change? 4

5 Review: Summarize write a summary of this lesson. Begin with the sentence: changes in ecosystems have two main causes. What are some ways in which people can change an ecosystem for the better? Review: Write a sentence that identifies three resources in an ecosystem. Explain how living things can change an ecosystem. How Do Ecosystems Change? 5

6 How Do Ecosystems Change? Lesson Focus Vocabulary: Resource Science concepts: How do ecosystems change over time? Reading skill focus: cause and effect. Look for the causes of changes in ecosystems. How ecosystems change Ecosystems change over time. Sometimes the changes are natural. Fires and floods cause changes. They can destroy habitats and kill many living things. Some living things survive. Seeds that survive grow into plants. Animals move back into the area to eat the plants. Living things change ecosystems. When beavers cut down trees to build a dam, they change the forest. Their dam changes the way the stream flows. Cause and effect: when beavers build a dam, what are the effects on the ecosystem? How Do Ecosystems Change? 6

7 How people change ecosystems People change ecosystems when they use the materials, or resources, from them. They cut down trees to build houses. They dig up rocks and stones to make roads. They use water that animals and plants depend on. Some of these changes harm the ecosystem. Car exhaust pollutes the air. Trash pollutes rivers and fields. People also can help ecosystems. Recycling, and picking up after ourselves goes a long way. Planting trees after a fire helps develop a new habitat. Bringing water to dry areas helps more plants grow. Cause and effect How are the ecosystems affected by people? Make a list of 5 or more things that you threw into the trash today. Compare your list with the two people who sit next to you Together, decide what items could have been recycled. 1.) 2.) 4.) 5.) 3.) How Do Ecosystems Change? 7

8 Effects of changes in ecosystems When one part of an ecosystem changes, it can affect the whole ecosystem. Changes such as forest fires cause some animals to run away, or stay and compete for the resources that are left. If there are not enough resources, populations get smaller. Some members die, and some others leave. If a change brings more resources, populations grow. Some organisms are able to adapt to changes in an ecosystem. More raccoons live near people than in the woods far away from people, why do you think that is? People build homes in the habitats of bears, deer, and other animals. What does this do to animals? Cause and effect: What happens to organisms when an ecosystem changes? Review: Summarize write a summary of this lesson. Begin with the sentence: changes in ecosystems have two main causes. How Do Ecosystems Change? 8

9 What are some ways in which people can change an ecosystem for the better? Review: Write a sentence that identifies three resources in an ecosystem. Explain how living things can change an ecosystem. How Do Ecosystems Change? 9