Section 2: Resources

Nutrient Cycles Game: Teacher Preparation

Materials

• Playing pieces for 4-6 players
• Small Post-it notes for students to write their names on to mark starting point
• Game board
• 54 playing cards
• Timer (a clock will work fine)

Background

Many students have a difficult time understanding how nutrients are cycled through an ecosystem. Ecosystem interactions are not obvious and students find it hard to grasp the underlying processes. Even if students understand how nutrients move in the process of decay, or how animals and plants get nutrients from their food, they have trouble understanding that all of these processes help to explain how nutrients flow on the scale of an ecosystem. This game aims to reinforce the idea that these interactions do not occur in a linear pattern, but that nutrients flow through ecosystems in cyclic patterns. Also, this game supports the understanding that matter is neither created nor destroyed in this process.

Goal

This game helps students think about how nutrients move through an ecosystem. As players, students represent the atoms of nutrients that move through a particular ecosystem. The goal of the game is to keep moving, therefore, whoever moves the most number of spaces (arrows) in a given amount of time wins the game. NOTE: Make sure your students realize that atoms of nutrients do not have goals and that there is no particular value to a nutrient in moving through the nutrient cycle quickly. The purpose of the goal in the game is to underscore the cyclic nature of nutrient recycling.

Getting Started

• The game board can be printed one of two ways, depending on your needs and printer availability. If you print Version 1, assemble the game board by taping the two halves together. If you choose to print out the full-sized game board, Version 2 (PDF: 671 KB), you will need access to large-scale printers, which are available at many copy centers. Laminating the board will make it last longer.
• Print the Encounter Cards on cardstock or other heavy paper and cut them out.
• Play the game with groups of 4-6 students.

Playing the Game

See Nutrient Cycles Game Directions for instruction on playing the game.

Questions for Students to Think About as They Play

1. Why do players move many spaces in some encounters and only one in others?
2. Why do players lose turns in other encounters?
3. Why is the path of nutrients shown with two yellow arrows in connected circles? What does that tell you about how atoms move through ecosystems?

Follow-up Questions

• Why was there no official start point or end point in this game?
• There is no official starting point to this game because in a circle, there is no start or finish. Letting students choose where they want to begin helps to show that matter is neither created nor destroyed. Rather, nutrients cycle through an ecosystem as part of a non-reducible cycle.
• Why is the path of nutrients shown with two yellow arrows in connected circles? If nutrients are transferred by interactions between two specific things, why aren't the lines drawn back and forth between two animals or plants on the board? What does that tell you about how atoms move through ecosystems?
• The pattern on the game board aims to reinforce the idea that nutrients do not flow in a linear pattern. An atom of carbon may flow from plant to insect to bird, or it may flow from bear to human to soil. The overall circular pattern aims to show that there is no one-way path that nutrients take in cycling in an ecosystem.
• What were some of the encounters that made you lose a turn? What do they tell you about how nutrients move in an ecosystem?
• Logging and harvesting of foodstuffs (in the game, mushrooms) can cause ecosystems to lose nutrients. In the case of logging, carbon stored inside woody and leaf material is lost when it is taken to the lumber mill, or to someone's home via a new table. When the vegetative cover that helped regulate nutrient cycling is removed, nutrients, especially nitrate, may also be washed away into the local watershed. In this way, large-scale deforestation can cause leaching.
• Because matter cannot be created or destroyed, however, students may argue that nutrients are never completely "lost." Assure them that this is a good point, but nutrients can be transferred out of a particular ecosystem. Because ecosystems may be fragile, even slight changes in nutrient cycling may have large impacts on the overall function of the ecosystem.
• Can ecosystems "lose" nutrients? If so, where do they go? If not, where do they go?

This question allows students to create their own model of nutrient cycling and apply what they've learned about how ecosystems function. Students' models should show that there is no starting point or ending point involved in nutrient cycling. After nutrients are broken down, they become available to organisms from non-living sources: soil, water, and air. In this way, they continue cycling throughout the ecosystem.

Students' models may look very similar to the pattern depicted on the game board, or they may be different. Students do not necessarily need to draw a perfect circle as shown on the game board. The key understanding that students' models should reflect is that there is no start point and no end point in the path of nutrient cycling.

• The game focused on moving through the cycle as many times as possible. This was to help make the game fun for the players. What are some instances when the recycling process might take a long time? What are some instances when it might happen quickly? How might slow or fast recycling impact the ecosystem? Ultimately, does the speed matter? Why or why not?
• The speed of nutrient recycling varies a great deal depending on what type of matter it is part of. Nutrients may stay "locked" in unusable forms for many thousands of years, such as in rock. In other cases, however, nutrients may cycle relatively quickly, such as in the decomposition of leaf litter on a forest floor. Speed of recycling is also a characteristic of the ecosystem. In a balanced ecosystem, the speed of recycling keeps pace with the demand.
• We've learned about the importance of decomposers, but what happens to the nutrients after they get broken down into soil?
• Once nutrients are broken down into soil, they may be absorbed through roots of plants, taken in by organisms in the soil, or leached into nearby watersheds via runoff. Nutrients then pass through the food chain as plants, are then eaten by herbivores, and then are eaten by omnivores or carnivores, etc. When organisms die, the nutrients are returned to the soil and the cycle begins again.
• Can you draw your own path to show how nutrients flow in an ecosystem?

Students should come up with their own models for thinking about how nutrients pass through an ecosystem. By creating a scenario that depicts a nutrient cycle, students think about the variables involved in the process of nutrient cycling.