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Effects of Environmental Change

Students investigate what might happen to plants and animals if their environment changes.

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Lesson Summary

Overview

In this lesson, students think about what might happen to plants and animals if their environment changed and they were faced with conditions to which they were not well adapted. First, students read The Great Kapok Tree: A Tale of the Amazon Rain Forest by Lynne Cherry. Then they watch a video about camouflage and learn that praying mantises are well suited for life in the rain forest. Next, students play a predator/prey game to simulate what might happen to the praying mantis if the rain forest were cut down. Finally, they use a Web activity to explore what would happen to living things if the concentration of oxygen in the air changed.

Objectives

  • Understand the interrelationship between organisms (plants and animals) and their environment
  • Understand that when environmental conditions change, some plants and animals survive and reproduce, while others die or move to new locations
  • Observe ways in which changes in environmental conditions affect the organisms living in that environment

Grade Level: 3-5

Suggested Time

  • Two 45-minute blocks

Multimedia Resources

Materials

Before the Lesson

  • Cut out the squares of green construction paper.
  • Make a copy of the handout for each student.

Background Information

Organisms can survive only in environments that meet their needs. The earth has many different environments, or biomes, and each has unique environmental conditions. These conditions, which include temperature, rainfall, soil quality, salinity, pH, and predators, present challenges to the living things born into that environment. Organisms have evolved features (structures and behaviors) that make them well adapted to tackle the challenges of the environment they live in. Changes in an organism's environment may result in death, migration, or survival of a few well-adapted individuals in the population.

The Lesson

Part I

1. Read aloud or have students read "The Great Kapok Tree: A Tale of the Amazon Rain Forest" by Lynne Cherry. Discuss the following:

  • What impact will chopping down the rain forest have on the animals, the soil, and on humans?

2. Show students the Evolution of Camouflage video and discuss the following:

  • The praying mantis is well disguised for life in a tropical tree. What might happen to praying mantises if all those trees were cut down?

3. Place a large piece of green print fabric on a table. Scatter the green paper squares randomly across the fabric. Have students gather around the table and stand with their backs to the fabric. Tell them not to turn around yet.

Explain to the class that the green print fabric represents the trees in the rain forest, the green squares represent praying mantises, and students are birds that feed on these insects. When you give the signal, students will turn around quickly and grab as many bugs as they can. They will get only five seconds to feed. When you say stop, students must turn back around. Give the signal when you and students are ready.

4. After students feed, have them count how many praying mantises are left on the fabric.

5. Replace the green fabric with the brown fabric and scatter the green paper squares across the fabric again. Explain to students that the brown fabric represents the rain forest after all the trees have been cut down. Have students repeat the feeding experiment.

6. After students feed, have them count how many praying mantises are left on the table this time. Discuss the results of the experiment.

  • What impact did changing the fabric color have on the number of green squares left on the table?
  • How does this model illustrate the impact that cutting down trees has on the praying mantis population?
  • What factors might be even more critical to mantis survival than lack of camouflage? (Example: food supply, shelter)
  • If trees were cut down would all the praying mantis die? What features might help some of the remaining mantises survive in a treeless environment? (Example: a brownish coloring)

7. After students feed, have them count how many praying mantises are left on the table this time. Discuss the results of the experiment.

  • What might happen to plants and animals if the amount of oxygen in the air changed?

8. Distribute a copy of the Handout: Atmospheric Oxygen Web Activity Worksheet (PDF) worksheet to each student. Have them answer the first two questions.

9. Have students conduct the Atmospheric Oxygen activity and answer the remaining questions on the handout. Then discuss their answers to the questions.

10. For homework, have students explain to their families why it's so important to preserve the tropical rain forest. Ask them to brainstorm things they as a family can do to help. (To encourage students to follow through, you might require them to bring in their brainstormed list signed by all family members participating in the activity.)

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