University of Maine Cooperative Extension   4-H Earth Connections "Creating Sustainable Communities for the 21st Century"
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AGE LEVEL = 8-12 (6-13) DURATION = 15-20 min. LEARNING STATION = Anywhere RELATED ACTIVITIES = ←→ Web of Life WHEN =

UNDERSTANDING: The dynamics of the food chain (web) and the balance found in nature.

MATERIALS:

• Several colored paper squares with a skull and crossbones emblem on them to represent poison.

• 3 x 5 Index cards or slips of paper

LESSON:

Warm-up: Give each child an index card to secretly write down a favorite animal or plant living in the area. Have them initial it. Collect the slips of paper and tell them they will be building a “Food Chain Pyramid.” Explain that the pyramid demonstrates the need for balance among all plants and animals for survival.

Activity: Ask: “What is energy? Where does it come from? What form of life uses the sun’s energy to make food?” When the children answer “plants,” introduce plants to the group (the children who wrote plants on their cards). Have the “plant-children” kneel down on all fours, close together in a line. Tell them that without the direct or indirect support of plants there would be no animals.

Then read off the names of animals and ask each “animal-child” whether they are a plant-eater or a meat-eater. Have the plant-eaters (herbivores) kneel in a line behind the plants and the carnivores stand in a line behind the carnivores. Since children often identify more with animals than plants, there may be more children in the upper levels of the pyramid than in the supporting lower levels. If so, explain that the “plant-children” can’t support all the animals, so some animals will have to become plants (encourage some children to switch). Supervise construction of the pyramid closely.

Wrap-up: After the children have created the pyramid, introduce a poison, using the poison cards. (You can make it more realistic by saying it is a hazardous chemical such as dioxin.) Pass a poison card to each of the plants. Have the herbivores (the kneeling layer) consume all the poison by passing the cards up the pyramid. Continue passing the poison up until the top consumer, standing at the top or back of the pyramid, has collected all the cards. Ask: “What will happen to the top consumer? Are we top consumers? What happens to us?” Give some examples of how poisons in our food or water affect us (illness, cancer, birth defects, deformities, etc.)

OPTIONS AND FURTHER EXPLORATIONS:

1. Illustrate how removing a producer (plant extinction) will cause an imbalance in the Food Chain Pyramid. Pull out the middle plant-child. Crash! Now there is no plant to support the animal kneeling behind. This could be a possible lead-in to a study on rain-forest destruction in South America, Central America and Mexico. Have the children learn about the causes of destruction and what’s at stake.
    

2. Introduce a new species (i.e., a new hawk or an invasive plant or animal). Again, an imbalance is caused. The hawk stands at the back and finds no space. This could be a good lead-in activity on the study of exotic (non-native) organisms and their effects on native animal and plant populations.