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Crocodiles!

Classroom Activity

Objective
To help students understand the need to evaluate the accuracy and reliability of information by comparing facts collected from a variety of sources.

• copy of "Whom to Believe?" student handout (PDF or HTML)

• Additional reference sources, including books, newspaper and popular magazine articles, science journals, and, if possible, access to a scientist and to the Internet.

1. Start by asking students if they have heard the phrase "Information Age." Why do they think that this label is used to refer to the present time in our society? Have the class brainstorm a list of forms of media and other information providers.

2. Divide the class into two groups and hand out the "Whom to Believe?" student handout. Assign one group the topic of anatomy and physiology. These students should particularly watch for and record information about the crocodiles' distinct internal and external body features and how they have adapted to varying environments. Assign the second group the topic of social behaviors. These students should record information about the crocodiles' courtship and mating rituals, hunting practices, and methods of communication.

3. After viewing the program, have students from each group share what they learned about crocodilian anatomy and physiology and social behaviors. Clarify any points where opinions might differ.

4. Regroup students into teams with the same or similar facts and have them research their facts using several sources, including reference books, newspapers and magazines, science journals, and, if possible, scientists and the Internet.

5. Once team members have completed their research, have them review what they learned, choose the source or sources they most believe, and provide reasons for their choices.

6. Lead a class discussion about what each team found and the choices teams made. Are there any trends regarding which sources students most believed? Was certain information more likely to be the same across all sources? Why? If some sources had conflicting facts, or didn't have any information about what was revealed in the NOVA program, why might that be? What conclusions can students draw from what they learned? Conclude with a discussion about what makes a source reliable.

7. As an extension, have students develop a class list of information literacy guidelines. You may wish to invite the school librarian and/or media specialist to share some suggestions with the class.

Students reporting about the anatomy and physiology of crocodiles may list:

• sharp teeth for gripping prey
• eyes that can see above and below the water's surface
• keen sense of smell
• control of buoyancy
• acidic digestive system that can digest bones, skin, and horns
• ability to remain underwater for long periods of time
• flexible diet

Students recording social behaviors may list:

• complex communication system, including courting calls and behaviors, territorial signals, contact calls, and distress calls
• courting and mating behaviors
• caring for eggs and young
• hunting in teams to kill large prey

What students discover from their research will vary. They may discover that numbers differ—such as how ancient crocodiles are, or how many exist in certain populations—or they may find that some sources give ranges of numbers instead of one definitive number. They are likely to find that facts regarding anatomy and physiology are more easily verified than facts involving numbers. Because some of the observations in the NOVA program were new, particularly regarding social behaviors, students may not find many corroborating sources.

In general, students may state that scientific sources such as journals and well-known reference materials such as encyclopedias are most reliable. Students may feel that educational materials and established Internet sites are also reliable. Sources such as popular magazines and personal Internet sites may be less reliable. Discuss criteria such as reviews and primary source information that lend credibility to sources.

Students will probably state that the reliability of sources is important to ensure that information is correct. Each of the job roles in Question 3 is passing the information along to others or making important decisions based on the information. Ask students to consider the consequences that misleading or incorrect information might have in each situation.

Books

Crocodiles and Alligators. by Charles A. Ross, S. Garnett, and T. Pyrzakowski, New York: Facts on File, Inc., 1989.
An encyclopedic and illustrated reference book with in-depth articles by leading crocodile researchers.

Crocodiles and Alligators of the World. by David Alderton and Bruce Tanner, New York: Facts on File, Inc., 1991.
Contains hundreds of photographs and facts about crocodilian species around the world.

Article

"The Hunt for Black Caiman." by John Throbjarnarson, International Wildlife, July/August 1999.
Chronicles a research trip to the Brazilian Amazon that looks for ways to combine conservation of a crocodilian population with economic opportunity for the local people.

Web Sites

NOVA Online—Crocodiles!
http://www.pbs.org/nova/crocs/
Includes interviews with crocodile researchers, facts on the 23 species of crocodilians, information on the challenges of working with crocodiles in the wild, and more. Launch date: Currently available.

Crocodilians Natural History and Conservation
http://www.crocodilian.com
Documents facts about crocodile species, houses photographs and sound bites, and provides links to other crocodile resources on the Web. Maintained by a crocodile scientist.

American Alligator
http://agrigator.ifas.ufl.edu/gators/
Provides information on American alligator populations, habitats, reproduction, behavior, interactions with humans, and safety tips.

The "Whom to Believe?" activity aligns with the following National Science Education Standards:

Grades 5-8

	Science Standard G: History and Nature of Science

Nature of science

• In areas where active research is being pursued and in which there is not a great deal of experimental or observational evidence and understanding, it is normal for scientists to differ with one another about the interpretation of the evidence or theory being considered. Different scientists may publish conflicting experimental results or might draw different conclusions from the same data.

Grades 9-12

	Science Standard G: History and Nature of Science

Nature of scientific knowledge

• Scientific explanations must meet certain criteria. First and foremost, they must be consistent with experimental and observational evidence about nature, and must make accurate predictions, when appropriate, about systems being studied. They should also be logical, respect the rules of evidence, be open to criticism, report methods and procedures, and make knowledge public. Explanations on how the natural world changes based on myths, personal beliefs, religious values, mystical inspiration, superstition, or authority may be personally useful and socially relevant, but they are not scientific.