Web of Life Game

Background Information:

A native river habitat is a fluid yet fragile community. Introduced species have altered, permanently in some cases, the natural food chain. The "Web of Life Game" actively demonstrates to students the impact zebra mussels have in a native river environment.

Dissolved oxygen, the available oxygen needed for species to live underwater, is a critical ingredient in a river habitat. All plants use carbon dioxide and water to produce oxygen during photosynthesis. In a river ecosystem, plants in the water produce oxygen; underwater animals, including zebra mussels, use the dissolved oxygen.When zebra mussel numbers increase rapidly, they use tremendous amounts of dissolved oxygen, which cause native fish to die.


Biological diversity, dissolved oxygen, ecosystem, food chain, food web, habitat, larval fish, native species, organic matter, zooplankton, veligers


30 double sided name tags with zebra mussel on the back of all.
  1. 10 tags named larval fish
  2. 10 tags named native mussels
  3. 10 tags named larger fish
3 diving ducks, name tags without zebra mussels on the back
150 blue game pieces- indicates dissolved oxygen
150 red game pieces - indicates zooplankton
Chalkboard, paper, pencil to record students' observations after the game has been concluded
Food pyramid diagram


The game is played in three rounds. As each round is completed, the students should discuss the changes that have occurred in the simulated ecosystem.

Setting up the game:

The instructions are based on 30 students. The game should be played in an area large enough to allow free movement. Begin the game with 10 larval fish, 10 native mussels, and 10 larger fish.

Objective of game:

To survive as long as possible.


Round One

1. Students put on the name tags; the teacher scatters the game pieces in a large area so all students have access to the game pieces.

2. At a signal from the teacher, the students scamble to collect as many game pieces as possible.

3. Each species needs a certain amount of dissolved oxygen and zooplankton to survive. Students determine which species have survived based on the species needs in the following chart.

species dissolved oxygen zooplankton
larval fish 6 6
native mussels 6 6
larger fish 10 10
zebra mussels* 2 2
diving ducks* 14 14

* These two species will participate later in the game.

4. Species must have at least the required number of the specific game pieces to survive; survivors remain the same species for the next round. Species that do not have the required number of game pieces die and become zebra mussels in the next round (by turning their tag over). Round Two

5. Collect and rescatter the game pieces. Have the students again collect as many game pieces as possible.

6. Repeat step thee to determine who survived. If many animals other than zebra mussels survive, repeat round two.

7.At the end of round two, each animal keeps the game pieces they collected in preparation for round three.

Round Three

8. Select three students at random to become diving ducks. The diving ducks may "eat" any surving animals other than zebra mussels by tagging them.

9. The diving ducks and fish take all the game pieces from each animal as it is tagged. The tagged animal now has been "eaten" and is out of the game.The round concludes when all game pieces have been collected.

10. Students discuss who has survived and why. Refer to the chart in step three.

11. Students and teachers discuss the game to illustrate the impact of zebra mussels on the native species. Students should understand the effects of zebra mussels and how they can destroy an ecosystem and its biodiversity.


Chart the results from the first and second round. Compare the results to see how in nature the food web interactions are constantly changing, More zebra mussels will reduce the number of larger fish because the zebra mussels are depleting necessary nutrients and life support.

These pages authored and maintained by Marcella Dawson. Revised 07/05/98. Copyright 1995 CRPC GirlTECH. All rights reserved. . Email your comments. These pages were developed through GirlTECH '96, a teacher training and student technology council program sponsored by the Center for Research on Parallel Computation (CRPC), a National Science Foundation Science and Technology Center.