- 30-60 minutes
- A timer
- Construction paper (4 colors from Food Token Chart) for tokens
- Red (top predators)
- Blue (secondary consumers)
- Brown (primary consumers)
- Green (producers)
- 1 envelope per student
- Feeding behavior cards for organisms. Make copies of the feeding behavior cards. Put one feeding behavior card and the appropriate number and color of food tokens into each envelope.
Part 1 – Discussion
- Describe the Great Lakes freshwater marsh habitat in terms of plants and animals that live there. Have students discuss what they know about marshes. What lives there? Discuss the organisms. Find out how these marshes may be important to the students (e.g., for fishing, bird watching, or collecting frogs and turtles).
- Also discuss the importance of the freshwater marshes with emphasis on their high productivity as a place for plants and animals to live. Introduce the terms “predator” and “prey” as well as “producers” and “consumers.” With the students’ help, integrate their knowledge to come up with useable and understandable definitions of these terms.
- Explain to the students that they are going to participate in an activity in which they will become freshwater marsh plants and animals to see how food chains and food webs work.
- Explain that organisms (students) need to eat in order to survive and that some of them depend on the others for that reason. Some students will be predators and others will be prey. Some students will be both: thus, they will need to eat other organisms but also avoid being eaten.
- Discuss this for a minute. Can there be more then one predator? Can predators eat predators? Build on previous knowledge of food chains to help learners understand these ideas.
- For simplicity in this game, organisms are assigned specific prey that they are allowed to consume. In reality, size of an organism is a complicating factor. For example, young bass and pike (fish) may in fact be prey to an adult crayfish. Similarly, even a small raccoon that gets too close to the water could become food for a large pike. There are endless examples of how the age or size of an organism could alter the structure of a food web. However, the end result of a food web is the transfer of energy and mass from producers to the top consumers or predators.
Part 2 – Pre-game Preparation
- Discuss the object of the game: By acting out the feeding motions of freshwater organisms, students will “capture” (tag) the appropriate prey and try to collect enough food tokens to survive.
- Pass out one envelope (containing feeding behavior cards and tokens) to each student. Each envelope contains the identity of one animal that lives in a freshwater marsh. Explain that their identity is a secret—they are not to tell others. The only way others will know what they are is by the way they feed.
- Have the students open their envelopes and see what animal they are and what feeding behavior they use. Remind them not to tell what they are. Emphasize that they are people pretending to be animals, and humans will not be able to move exactly like animals.
- Review the organisms and their feeding behaviors but allow students to improvise.
Part 3 – Explain the Rules
- Each student represents a producer or a consumer. Consumers will play the role of predators, prey or both.
- Each producer has 30 green food tokens, representing 30 individual marsh plants of the same species.
- Each primary consumer (macroinvertebrates, snails, clams) starts with 10 food tokens; secondary consumers (crayfish, frogs, small fish, bluegill) start with 5 food tokens, and top predators begin with only 1 red token. Each token represents an individual organism of the same species.
- During the first cycle, or year, each consumer will need to eat enough food to survive and grow and thus to reproduce. Consumers collect tokens by identifying the feeding behaviors of their prey and then tagging them.
- When someone is tagged they have to give up a token. Each food token a consumer consumes will represent a new organism of the consumer species.
- People, raccoons, blue herons, pike and bass are at the top of the food web and must consume 10 organisms to survive.
- Bluegill, small fish, crayfish and frogs are secondary consumers (which may be predators or prey). They will need to consume and have in possession 5 organisms at the end of the year in order to survive. However, they must also avoid predation. If captured, they must give up 1 token.
- Clams, snails and macro-invertebrates (primary consumers) need only to end the year with 1 token to survive. However, they must also eat enough to account for predation or they will die, too.
- Plants can die, and they are directly returned to the system as nutrients; therefore, plants need nothing to eat, but if these students are out of tokens then they must wait until another organism dies due to lack of food (i.e., a student is eliminated after losing all tokens) and returns enough nutrients to the ground to create new plant growth.
- Any organism that does not end the year with enough tokens to survive will return what they do have to the ground for consumption by plants and other organisms that feed on decaying organisms.
- It is important that each organism continues to act out what it is. If an organism forgets what different pantomimes represent, then it is up to them to investigate, if they want to survive. However, they will have to realize that food webs are not forgiving, and a nosey little fish that investigates a pike will become food for a pike!
Part 4 – Play the Game
- Establish a play area (inside a classroom or outside) and have all producers take their envelopes with them, spread out on the playing field, and start acting out their roles.
- Next, tell everyone else to begin to pantomime their respective behaviors, capture their prey by tagging others, and secure a food token from them, placing it in their envelope.
- End the game after most top predators have gotten 10 food tokens.
- Tell the students to hold onto their food envelopes so that they can participate in class discussion.
Part 5 – Discuss the Results
- Did every top predator “fill up” by getting 10 food tokens during the cycle or year? If not, why not? (Some animals are more selective in feeding preferences and therefore may have a more difficult time finding food.)
- Talk about the different way the animals are connected to each other and the producers.
- Be sure that the supporting roles of decomposers do not get overlooked. Decomposers are responsible for breaking down dead organisms into nutrients usable by plants for growth.
- Draw a food web based on what feeding interactions took place during the game. Discuss the path that some tokens took to get from the bottom of the web to the very top.
- Discuss how many plants and lower organisms it took to support the top of the food web.
- Replay the simulation for a second round or year, leaving the tokens distributed as they were after the first round. Tokens left over from an organism that died during the first year will be returned to the ground for consumption by organisms such as the plants and crayfish.
- Summarize by emphasizing the importance of freshwater marshes. These marshes provide habitat for a variety of different kinds of animals.
Adapted for the Great Lakes Education Program with permission from “Marsh Munchers,” Project WILD Aquatic. Modified by Brandon Schroeder, Michigan Sea Grant and Michigan State University.