Standard 6: "How culture and experience influence people's perceptions of places and regions"
Standard 14: "How human actions modify the physical environment"
Standard 18: "How to apply geography to interpret the present and plan for the future"
Have students visit the
National Geographic Kids magazine article "
The Weird World of Frogs" to learn some amazing facts about frogs. Tell students this lesson will teach them some other amazing things about frogs.
Ask students if they have ever heard frogs make noise late at night. Is it a sound they enjoyed or did it keep them awake? Have students listen to the collection of sounds available at the Exploratorium's Frog Tracker (Macromedia Shockwave required). Tell students that frog calls are generally a signal of mating, though many frogs call out throughout the year. But some frogs have another way of calling out, or signaling, distress—and they don't even know they're doing it!
Activity 1:
Have students spend some time exploring the frogs on the
Frog Tracker (
Macromedia Shockwave required) by opening the pages for the individual frogs (Note: If students have difficulty opening the frog pages from the activity, they can access almost all of the pictures and sound from
this page). Ask students to notice the coloring of the frogs, and then have them color this National Geographic Coloring Book's
Giant Tree Frogs page. Point out that this page represents a specific species of frog, but you want students to "transform" the frog into their favorite through the use of color.
Explain to students that animal transformations happen all the time. Tadpoles turn into frogs; caterpillars turn into butterflies, and so on. Explain that in this lesson, students will be learning about a man who studies frogs and the ways in which harmful chemicals in the environment are causing them to transform—and not necessarily for the better.
Activity 2:
Introduce students to Tyrone Hayes by summarizing for them some of the information on his National Geographic Emerging Explorers profile page. Then, show them this video from the Exploratorium in which Dr. Hayes explains his fascination with frogs (audio file, RealPlayer required).
Ask students what they think of Dr. Hayes. Do they like to look at "crawly things?" What do they think about Dr. Hayes and his opinion about frogs? How does he believe that frogs can help humans?
Explain to students that one of the ways Dr. Hayes learns about frogs is by studying them in their natural habitats, and another way is by watching them in a laboratory. Dr. Hayes learns about ways frogs may be affected by changes in their environment (like water pollution), and then does experiments with frogs in his lab to test his theories about what might be harmful to them. Ask students why they think this is important work.
Activity 3:
Share some of the students' coloring sheets and ask them to describe what they liked about the colors of the frogs they saw in the web activity. Explain to students that the frogs Dr. Hayes studies do something interesting with their colors—though not on purpose.
Show students the picture of the male and female African reed frogs on the Exploratorium site. Explain that the African reed frog has different colors to show which ones are male and which ones are female. Then explain that Dr. Hayes has found that some chemicals that get into the water cause problems for the frogs that make them change colors. Show students the pictures on the Cancer Connection page. Point out the control frog in the upper left of the grid. Explain that with that frog Dr. Hayes didn't put any chemicals in its water, but that with all the other frogs, different chemicals were added to their water to see if they were dangerous for the frogs. Draw students' attention to the ways in which many of the frogs changed to look more like the females in coloration. Explain that these changes indicate to Dr. Hayes and many others that the chemicals introduced had a negative effect on the frogs—and therefore could be chemicals that cause problems for humans.
Explain to students that these studies are giving us a great deal of information about chemicals that get into water in a variety of ways (runoff from farms, industrial pollution, waste disposal), and the types of dangers they may pose for humans. For more information about groundwater pollution from pesticides, visit the U.S. Geological Survey’s Pesticides in Groundwater site.
Ask students to think about what they might do to help prevent the types of water pollution that can harm frogs—and humans. Visit the
Earth Day Network's Water for Life campaign page and assign students to work with a family member to learn more about one of the
Community Water Stories. Have students create a poster or drawing that illustrates what the problem is, and then share their work in class by explaining the drawing and what they think about the issue. (These community stories are brief and can be printed to send home with students if Internet access is an issue in students' homes.)
Student presentations should reflect a clear understanding of the information they have studied. While there are clearly varied opinions on the issue of atrazine use, students should demonstrate their awareness of the importance of the studies.
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