Activity 3.5: Tracing Energy Through an Ecosystem (30 min)

Using Slide 3, remind students of how they traced energy movement with yellow twist ties in Activity 3.2 Carbon Dice Game. Ask: Where did most of the twist ties end up in the game? Solicit student ideas about energy flow through carbon pools from the Game.

Accommodation: Before beginning this Activity, review the results of 3.2 The Carbon Dice Game.

Use Slides 4-13 to help students think about the Energy Flow Question and the process of tracing energy. These slides are animated, so view them in presentation mode for the best effect. Be sure to explain that all energy in the ecosystem is eventually converted into heat energy, which is released to the atmosphere. Heat energy dissipates, moves through the atmosphere and ultimately is radiated into space.

Accommodation: As you go through Slides 4-13, provide students with guided notes that include the information from the slides with a few words taken out so students can fill in the information during the lecture. Encourage students to use different colors to depict different forms of energy (i.e. yellow for sunlight energy, green for chemical energy, and red for heat and motion energy) while taking notes.

Give each student a copy of 3.5 Tracing Energy Worksheet. Have students try to complete the first page on their own, and then have them compare with a neighbor to see if they both agree on all of the processes.

Show Slide 14 of 3.5 Tracing Energy PPT while they work.

Have students answer questions 4-7 on the second page of the 3.5 Tracing Energy Worksheet based on what they just learned.

Use Slide 15 to discuss the answer to the Energy Flow Question. Have students compare this to the answers that they wrote on their worksheet.

Review energy flows in an ecosystem with the animations on Slide 16. Be sure to view it in presentation mode to see the animations.

• Use Slides 17-18 to link energy flows with the organic matter pyramid.
• On Slide 17, ask students what they think the distribution of energy looks like in an ecosystem. Have them explain their reasoning to the class.
• Slide 18 explains it would look the same as the organic matter pyramid.

Use Slides 19-22 to review with students how matter and energy move through an ecosystem.

• Slide 19 show the summative figure depicting how matter and energy move through an ecosystem.
• Slides 20-21 provide four key concepts from this Lesson about matter and energy in an ecosystem. Discuss with students how each of the concepts is portrayed in the figures.
• Return to the figure on Slide 22 to ask some more in-depth questions about its content, such as: Where is the organic matter pyramid on the figure? Why doesn’t energy cycle like matter? What ultimately happens to most of the carbon that enters the ecosystem through photosynthesis? (answer: it is returned to the atmosphere through cellular respiration carried out by producers, herbivore, carnivores, and decomposers)

Show Slide 23 of the 3.5 Tracing Energy PPT.

• Conclusions: What is the only way that energy gets into living plants, animals, and decomposers?
• Predictions: How are matter cycling and energy flow alike and different?
• On a sheet of paper or a sticky note, have students individually answer the exit ticket questions. Depending on time, you may have students answer both questions, assign students to answer a particular question, or let students choose one question to answer. Collect and review the answers.
• The conclusions question will provide you with information about what your students are taking away from the activity. Student answers to the conclusions question can be used on the Driving Questions Board (if you are using one). The predictions question allows students to begin thinking about the next activity and allows you to assess their current ideas as you prepare for the next activity. Student answers to the predictions question can be used as a lead into the next activity.