Activity 3.6: Explaining Patterns in Ecosystems (30 min)

Display Slide 3. Tell students that at this point in the unit they should have evidence to support an explanation for the pattern in the organic matter pyramid. The Explanations Tool in this activity will help them record their ideas about the Large-Scale Four Questions and combine these ideas into a scientific explanation.

• Display Slide 4. Pass out the 3.6 Telling the Ecosystems Story Reading to each student. Have students read the section on Lessons 1, 2, and 3.
• Discuss how this section summarizes what students have learned about ecosystems so far.

If you decided to use the Big Idea Probe: Wolves and Deer, have students complete it and share their ideas for a third time. See Assessing Big Idea Probe: Wolves and Deer and Using Big Idea Probes

• Discuss how their ideas have changed since the beginning of the unit.

Show Slide 5. Give each student one copy of the 3.6 Explanations Tool for Ecosystems. Tell students that in order to make sure we have the pieces for a complete explanation they will first compose their ideas in pieces that correspond with the first three of the Four Questions.

• Give students 10 minutes to complete the questions on the front of the Explanations Tool.

After students have had a chance to record their own ideas, have them find a partner and swap papers. Have the partners read each other’s explanations and compare. Encourage them to look for differences between each other’s ideas. They can refer to the Large Scale Four Questions Poster (or Handout). Have them look for key questions:

• Does the explanation follow the rules (atoms and energy last forever?)
• Does the explanation use evidence from the atomic-molecular, cellular, and macroscopic scales to answer the question?
• Does the explanation explain why the biomass pyramid pattern happens in ecosystems?

Give students a chance to revise their explanations based on the results of their discussion with a partner.

Use Slide 7 to have the students discuss the Carbon Pools question on their 3.6 Explanations Tool for Ecosystems.

• If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

Use Slide 8 to have the students discuss the Carbon Cycling question on their 3.6 Explanations Tool for Ecosystems.

• If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

Use Slide 9 to have the students discuss the Energy Flow question on their 3.6 Explanations Tool for Ecosystems.

• If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

Overview their answers to the Four Large-Scale Questions so far. Give students an additional 10 minutes to write a paragraph explaining the organic matter pyramid on the back of the Explanation Tool: Why does the meadow ecosystem need so much grass to support so few foxes?

Display Slide 10 for the full explanation. Have students use the Large-Scale Four Questions Handout with Checklist to check that their story includes each of the parts (carbon pools, carbon cycling, and energy flow).

• If students don’t have all three parts in their explanation, instruct them to add to their explanation using a different colored writing utensil.
• If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

Show Slide 11 of the PPT.

• Have students read the section on Lessons 4 and 5 in 3.6 Telling the Ecosystems Story Reading.
• If you are not teaching Lesson 4, tell students, but still have them read the subsection on Lesson 4.
• Discuss the section as a class. Include discussion of the new vocabulary. Have students explain the new vocabulary in their own words.

Show Slide 12 of the 3.6 Explaining Patterns in Ecosystem PPT.

• Pass out a Learning Tracking Tool for Ecosystems to each student.
• Have students write the activity chunk name in the first column, "Matter Cycles and Energy Flows, 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