Marine Food Web Simulation A simulation of the dynamics of food webs and predator/prey relationships in the marine environment
by John Ogletree Preparation: 1. Prepare a set of food web I.D. cards according to Grade levels: 4-6 the numbers of organisms shown on the “Food Web Subject areas: art, science Organisms” chart (see next page). The organisms listed Key concepts: primary producers, predators, prey, food correspond to those in the food web example given, chain, marine food web and the numbers are for a group of 22 students. Add organisms (and cards) as needed to ensure that each Skills: listening, observing, cooperating as a group student will have one card. In addition, make extra Location: indoors or outdoors phytoplankton cards for use as described in Step 6 Time: 5-8 minutes per round below. Materials: flipchart paper, index cards, drawings or To make the cards, glue photos or drawings of photographs of marine organisms, glue, 2 metal cans, 2 the organisms on card stock. (Wall calendars having small stones, 2 wooden sticks, stopwatch or watch with a a marine theme are an excellent source of photos.) second hand Alternatively, have students research the marine organ- isms and make drawings of them on cards as a means lants, with their ability to transform the of learning the characteristics of these organisms. If sun’s energy into food through photo- possible, laminate the cards. synthesis, are called the primary pro- 2. On a large sheet of paper or chalkboard, draw the ducers of our global ecosystems; and food web (see “Marine Food Web,” next page). P microscopic plants called phytoplankton 3. On a large sheet of paper or chalkboard, list the that drift near the surface of the oceans account for organisms and their identifying sounds, as shown on more productivity than all the plants on land. The the “Food Web Organisms” chart. transfer of food energy from a plant source through a succession of animals eating and being eaten is called Procedure: a food chain. Food chains are in turn linked together 1. Introduce the “Marine Food Web” chart and discuss in a complex interlocking pattern called a food web. the concepts of food chains and food webs. Ask stu- In this activity, students play the roles of marine dents to identify the various food chains in the web organisms in a food web, and must find food while (e.g., algae ➞ periwinkle ➞ dogwinkle ➞ crab ➞ hu- avoiding being eaten by their predators. For the pur- man). As each food chain is discussed, show the cards poses of the game, the web example is greatly simpli- depicting those organisms so that students become fied, with no reference to decomposers, zooplankton, familiar with all of the members of the web. or many other groups of marine organisms. As the 2. Outline an area with boundaries to represent an area students learn more about the marine environment of the ocean. Assign a marine organism to each student they may wish to play the game using different species. by handing out the food web cards.
Outcomes: 3. Explain to the group that together they represent It is expected that students will: the ten different marine organisms in the food web, and they must catch food for themselves recognize the importance of while avoiding being eaten by a predator. marine food producers Allow a few seconds for students to find their recognize seven to eight position in a food chain and review which individual marine organ- organisms are their prey and predators. isms 4. To begin the game, identify three or four food ask students to move chains in the marine food slowly around the
Anne Stewart, Bamfield Marine Sciences Centre web “ocean,” holding their cards in front of them
115 Teaching Green: The Elementary Years so that they are visible. Ex- Note: In lower grades, the plain that, to catch their prey, Marine Food Web simulation is easier to run
predators must touch the using only visual identifica- ➤Human ➤
card of the prey organism. ➤ ➤ tion of animals. For older If a prey organism is caught, students, the sound identifi-
Bird Crab it has been eaten and must ➤ ➤ cation is a good representa-
➤ ➤ leave the game (go outside ➤ tion of the importance, for Fish Starfish the boundary). Begin timing ➤ some marine animals, of ➤ the round. having a highly developed Scallop Dogwinkle 5. Continue the round until sense of hearing. ➤ all of the prey have been ➤ 8. After handing out the food
Sea Urchin Periwinkle consumed. Record the time. ➤ ➤ web cards, give students a few seconds to review which 6. Discuss the round and Phytoplankton how quickly prey organisms organisms are their prey and were eaten. Ask students how predators and the sounds the simulation might be changed so that more prey these organisms make. Then ask them to keep their are available and the food web can be sustained for a cards out of view as they move slowly around the longer period of time. Then incorporate some of their ocean, making their identifying sounds and listening ideas in ensuing rounds of the game. Variations might for the sounds of the organisms they feed on. To catch include the following: their prey, predators must touch the prey organism and show their own card as “predator I.D.” Simulate reproduction and/or the migration of animals into that area of the ocean by allowing some 9. Graph the times of all of the rounds and conclude by of the captured prey organisms to return to the game discussing the factors that helped to sustain the food following a “death interval.” web the longest (e.g., migration, reproduction, increas- ing the number of primary producers or of other or- Change the composition of the food web so that ganisms at the lower ends of food chains). as many as four-fifths of the prey organisms return as Extensions: phytoplankton (additional phytoplankton cards are needed for this variation). Discuss how an oil spill, toxic chemical, or other human interference might affect the food web. Collect and redistribute the cards between each round Adapt the activity to another ecosystem under so that students have the opportunity to play the roles of different organisms. Continue timing the rounds. investigation. 7. After several rounds, introduce a twist: explain that This activity was designed by Cheryl Rowatt and modi- the object of the game will remain the same, but the fied by John Ogletree, professor of Education at the Uni- only way the players will be able to identify their preda- versity of Western Ontario in London, Ontario. tors and/or prey is by the unique sounds they make. Introduce the “Food Web Organisms” chart and, as a group, practice making the sounds Food Web Organisms described. Alterna- tively, invite students Organism Number Identifying sound to suggest sounds Phytoplankton 4 Say “photosynthesis” or “making food” for each organism, and record these on Periwinkle 3 Say “graze, graze” a chart. The impor- Sea urchin 3 Say “spiny-spiny” tant thing is that Scallop 3 Say “squirt, squirt” each organism has a unique sound and Dogwinkle 2 Rotate stones in can (drilling sound) that the group Starfish 2 Say “yum-yum” agrees on how these Fish 2 Hum sounds are produced so that everyone will Bird 1 Whistle be able to recognize Crab 1 Snap fingers (claws) or strike sticks them. Human 1 Remain quiet
116 Plants and Animals