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Ecosystems | Activity 3.3

Activity 3.3: Tracing Carbon Through an Ecosystem (30 min)

In this activity students shift to following a pulse of 500 carbon atoms through all the carbon pools in an ecosystem, considering the carbon transforming processes (eating, digestion, biosynthesis, photosynthesis, cellular respiration and death/defecation) that move atoms from one pool to another. They see how the pattern they observed in Lesson 2—the organic matter pyramid—emerges from these carbon-transforming processes.

Materials You Provide

Resources Provided


Print a copy for each student of 3.3 Tracing Carbon Through Ecosystems Graphic Organizer. Set up a computer and projector for 3.3 Tracing Carbon Through Ecosystems PPT.


1. Use the instructional model to show students where they are in the course of the unit.


Use the discussion as a formative assessment: if your students are having trouble describing carbon atoms moving through pools, you may want to review the graphic organizer and the patterns.


For this activity you will need to revisit some materials from Activity 3.2 Carbon Dice Game.


If students need additional practice thinking about carbon movement, use the 3.3 Supplement PPT with animations of carbon movement.

Extending the Learning

Challenge the students to think about what would happen to a plant or animal in this ecosystem if they could not perform cellular respiration.