Lesson plan: Disappearing frogs and the environment

September 8, 2000
Web posted at: 10:34 PM EDT (0234 GMT)

Objectives

Students will:

• Interpret the "canary in the coal mine" theory.
• Relate theory to practical applications regarding amphibians and the ecosystem.
• Research and present theories regarding causes of declining amphibian population.

Standards

National Science Standards

High school students will develop an understanding that human beings live within the world's ecosystems. Increasingly, humans modify ecosystems as a result of population growth, technology and consumption. Human destruction of habitats through direct harvesting, pollution, atmospheric changes and other factors is threatening global stability, and if not addressed, ecosystems will be irreversibly affected.

Materials

CNNfyi article, "Vanishing toads"
Internet access
Materials for charts and drawings

Suggested time

One class period

Procedures

1. By way of preparation, ask students to explain the "canary in the coal mine" theory. Explain to the class that amphibians are indicator species.
2. After students have read the CNNfyi article "Vanishing toads," ask them the following:

• What are amphibians? What are some of the endangered ones? Why? What are herpetologists? Why is it easier for biologists to assess frog populations than other amphibians? According to scientists, what is the connection between frogs and the environment? According to University of New Orleans assistant professor Joe Pechmann, what circumstances could be stressing the planet?
• Canadian student Jeff Houlahan said that what happens to frogs could happen to us. What does he mean by this? Do you agree or disagree with this assertion? Why or why not? How would you prove or disprove this idea?

3. Direct students to online and/or media resources to answer the following questions: What is a food web? Where are humans in this web in relationship to the amphibian group? What is the relationship between humans and other species in the food chain? What are some environmental effects that are evident throughout the chain? What are the causes?

Accommodation

Spatial intelligence: Instruct students to create a world map of the locations of amphibians whose numbers are declining. They may use online or media resources to find the locations of these endangered species. Have students place symbols or pushpins on the designated areas of population.

Assessment

Have students organize their findings to present a food web to the class. Ask them to include environmental stressors and the living things affected by them. Direct them to show the relationship of frogs to the environment and the effects that the declining population has created. Instruct students also to create a web that depicts the relationship of frogs and humans. Encourage students to be creative in their presentations, using multimedia applications, charts, drawings or props.

Challenge

Share with the class the global effects that environmental stresses cause. Have groups identify environmental stressors and research the living things harmed by them. Direct students to research online resources to find the viewpoints of scientists, conservationists/environmentalists, developers and average people on the subject of stressing the environment. Assign groups to represent each point of view -- scientists, conservationists, environmentalists, developers and citizens. Direct them to present their findings from the perspective views.

North American Amphibian Monitoring Program
Frogland
Endangered amphibians
Frogs and toads

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