Directions 1. Use the instructional model to show students where they are in the course of the unit. Show Slide 2 of the 4.4 Seasonal Changes and Ecosystem Disturbances PPT. 2. Review the Constant and Changing Fluxes Models and introduce the Seasons and Disturbances Model. Show Slide 3. Review what students concluded from the Constant and Changing Fluxes Models. Show Slide 4. Pass out the 4.4 Computer Model for Seasons and Disturbances Handout to each student. In partners or as a whole class, have students read the handout until Part A. Discuss what students learned from the first two models and how Model 3 is different. 3. Students run the simulation. Pass out 4.4 Computer Model for Seasons and Disturbances Worksheet to each student. Have students follow the directions on 4.4 Computer Model for Seasons and Disturbances Handout to complete Part A and B on their worksheet. (Optional) Use Slides 5-11 to go through Part A and B with the students. The questions can be completed together using the slides. 4. Students continue to run the simulation. Have students follow the directions on 4.4 Computer Model for Seasons and Disturbances Handout to complete Part C on their worksheet. (Optional) Use Slide 12 to go through Part C with the students. 5. Students read about disturbances in real ecosystems. Show Slide 13. Have students read the last section of 4.4 Computer Model for Seasons and Disturbances Handout about disturbances in real ecosystems. Have students answer Part D of their worksheet. 6. Discuss the patterns Show Slide 14. Have students share and discuss their answers to questions. 7. (Optional) Students read about and discuss the effects of fire as a disturbance. Pass out the 4.4 Fire Reading. Have student read 4.4 Fire Reading using the Questions, Connections, Questions Student Reading Strategy. See the Questions, Connections, Questions Reading Strategy Educator Resource document for information about how to engage students with this strategy. After pairs are finished reading, have students share with the class what they found interesting and any questions they have. 8. Have a discussion to complete the Learning Tracking Tool for this activity. Show slide 15 of the 4.4 Seasonal Changes and Ecosystem Disturbances PPT. Pass out a Learning Tracking Tool for Ecosystems to each student. Have students write the activity chunk name in the first column, "Carbon Pools and Fluxes, Explainers" Have a class discussion about what students did during the activity chunk. When you come to consensus as a class, have students record the answer in the second column of the tool. Have a class discussion about what students figured out during the activity chunk that will help them in answering the unit driving question. When you come to consensus as a class, have students record the answer in the third column of the tool. Have a class discussion about what students are wondering now that will help them move towards answering the unit driving question. Have students record the questions in the fourth column of the tool. Have students keep their Learning Tracking Tool for Ecosystems for future activities. Example Learning Tracking Tool Activity Chunk What Did We Do? What Did We Figure Out? What Are We Asking Now? Carbon Pools and Fluxes Explainer Explain changes in ecosystems by keeping track of carbon pools and carbon fluxes. Carbon pools are stable when fluxes are balanced and change size when fluxes are unbalanced. Seasons and disturbances cause unbalanced fluxes. How do humans depend on and disturb ecosystems?
