SCIENCE & AND GLOBAL GLOBAL ISSUES/BIOLOGY ISSUES/BIOLOGY • ECOLOGY • ECOLOGY DOING THE ACTIVITY 2 Students should complete the carbon cycle simulation on the Science and Global Issues page of the SEPUP website (sepuplhs.org/sgi). All directions for this s imulation are on Student Sheet 8.1, “Carbon Cycle,” which can be downloaded from the same website. SCIENCE & GLOBAL ISSUES/BIOLOGY • ECOLOGY Procedure 1. With your partner, visit the Science and Global Issues page of the SEPUP website at sepuplhs.org/sgi and go to the carbon cycle simulation. Use your student sheet to guide you through the simulation. 2 3 Analysis 1. What happens to the total amount of carbon as it moves through the carbon cycle? 2. In what ways does human activity affect the carbon cycle? Support your answer with evidence. 3. Explain one possible path a carbon molecule might take if it began in a small fish and ended up in a blade of grass. FOLLOW-UP 3 (UC ASSESSMENT) Discuss with the class how the pre- and post- industrial carbon cycles differ. See the S cience and Global Issues website (sepuplhs.org/sgi) for more information on how to hold this class discussion. Analysis Question 3 is an opportunity for you to use the UNDERSTANDING CONCEPTS (UC) hd^aVcY YZig^ijhh [^gZh$ gZh$ XdbWjhi^dc eaVcih XdVagZhZgkZh Scoring Guide to assess students’ understanding of the carbon cycle. dXZVc lViZgh dXZVc W^dbVhh EXTENSION Slide presentations on other biochemical cycles are available on the Science and Global Issues page of the SEPUP website (sepuplhs.org/sgi). d^agZhZgkZh This diagram of the carbon cycle shows how carbon is exchanged between carbon reservoirs by processes that involve geological changes and organism interactions. 98 SAMPLE RESPONSES 1. The total amount of carbon atoms in the system stays the same even though carbon moves from reservoir to reservoir. 3. 2. The carbon cycle shows how the carbon moves between carbon reservoirs on earth and in the earth’s atmosphere. Humans can affect a part of the carbon cycle by doing such things as cutting down a forest. When the forest is removed, the trees will no longer remove carbon from the atmosphere. This means that more carbon dioxide may build up in the atmosphere reservoir if it is not removed in some other way. Thus, humans can create imbalances in the natural cycle of carbon on Earth. Sample Level-3 Response Carbon is a part of molecules in the body of a fish. The fish respires and releases carbon dioxide into the water. The carbon dioxide is transferred from the water into the atmosphere. The grass takes in the carbon dioxide from the atmosphere and uses it during photosynthesis to create carbon-containing molecules. These carboncontaining molecules from photosynthesis are incor porated into the blade of grass. 156 A correct and complete answer would explain that the carbon would pass through reservoirs in the carbon cycle, eventually traveling from the small fish to a blade of grass. Students’ answers will vary. (UC ASSESSMENT)