Web of Life, The (Adapted from Project Learning Tree (FBCEC)

Summary:

Participants will learn that all living things are interdependent. They will discover how a source of food, water or shelter for one animal supports the rest of the animals in a habitat.

Grade Level:

K-12

Recommended Setting:

Any large area

Outdoor Activity:

No

Location:

Fred Berry Conservation Education Center, Yellville, AR

Contact:

Education Program Coordinator, 870-449-3484

Duration:

30 - 45 minutes

Suggested Number of Participants:

Up to 24

Objectives:

  • Understand that interrelated food chains compose a food web.
  • Demonstrate flows of energy from one organism to another.
  • Identify organisms as decomposers, producers or consumers.
  • Create a written and/or visual scenario predicting sequences of change within a food web when species are lost.

Key Terms*:

Community

Consumer

Decomposer

Food chain

Habitat

Limiting factors

Producer

*See glossary for definations

Materials:

Copy of “A Sand County Almanac” by Aldo Leopold (optional)

Pictures of local animals/plants-with holes and strings

Web of Life, page 194 in Project Learning Tree curriculum guide (optional)

Yarn

Background:

An animal’s habitat provides its basic needs: food, water, shelter and space. At the foundation are the producers, which are primarily plants that produce food for themselves. Animals that eat producers are called first-level consumers. Second-level consumers feed on first-level consumers, etc. All the organisms within a community, and the resources that support them, are directly or indirectly related.

Procedure:

  1. Arrange the participants in a circle with the instructor in the middle.
  2. Ask the participants to identify some animals and plants that live in Arkansas. Give each of them a plant or animal card and have them put it on like a necklace.
  3. Ask what every living thing must have to survive. When someone says “sunlight,” begin the game there. Give that participant a sunlight card and the ball of yarn.
  4. Next ask the participant to name something that uses the sun for food. Have the sunlight participant hold onto the end of the yarn and toss the ball of yarn to a participant with a plant card. Explain that a plant is a producer. It makes its own food and is eaten by an animal, a consumer.
  5. Ask what would eat that plant and have the plant hold onto the yarn and toss the ball to an animal that would eat it. (The group may want to broaden the possibilities by tossing to anything the plant would be used for, such as shelter.)
  6. Continue until all participants are holding the yarn and a web has been constructed in the center of the circle. If the game gets to a point where there is nothing that would eat the animal (top of the food chain), ask, “What would that animal eat?” and continue from there. A decomposer could be introduced at this point since they would eat a dead animal at the top of a food chain.
  7. When the yarn is used up, introduce a limiting factor that would affect the web. For example, imagine that road construction eliminated some habitat. Select a couple of species that might be affected and have them tug on the string. Ask the others if they could feel the tug. Explain that in the food web, all the living things are somehow, either directly or indirectly, affected when populations change. The effect can be slight or great.
  8. To demonstrate, tell participants that one of the species was affected so adversely that it is now out of the food chain. Have the participant representing that species drop the string. Note any changes in the web.
  9. Next, ask the participants that were directly connected by the string to that participant how this affects them. Participants representing animals that eat the missing species will also need to drop the string. Next are the ones that eat those animals. Continue in this manner. Eventually each participant should be affected. Ask if they could feel a difference in the web each time a species was lost?

Modifications:

  • For older children: Continue discussion by asking them to imagine a habitat with wolves. What would happen to other living things if the wolves died? Then read “Thinking Like a Mountain” from Aldo Leopold’s “Sand County Almanac.”
  • Another option is to have participants select an organism and write a scenario where changes might occur within that organism’s environment. If there is time and the participants are old enough, these scenarios could be illustrated and/or shared with the group.

Review:

  • Describe a food web for a woodland habitat.
  • Compare producers, consumers and decomposers of the food chain.
  • Explain the effect of an extended drought in a food web.

Resources:

Sweeney, Linda Booth (2001). When a Butterfly Sneezes – A Guide for Helping Kids Explore Interconnections in Our World Through Favorite Stories. Pegasus Communications, Inc., Waltham, MA.

Glossary:

Community – all the different populations of an area

Consumer – in ecology, an organism, usually an animal, that feeds on other organisms and their remains; classified as primary consumers (herbivores), secondary consumers (carnivores) and microconsumers (decomposers)

Decomposer – an organism that breaks down large chemicals from dead organisms into small chemicals and returns important materials to the soil and water

Food chain – feeding order in an ecological community that passes food energy from one organism to another as each consumes a lower member and in turn is preyed upon by a higher member

Habitat – an arrangement of food, water, shelter or cover, and space suitable to animals’ needs

Limiting factors – element that affects the amount of wildlife a habitat can sustain, including food, water, space, predators, disease and pollution

Producer – an organism that creates its own food from inorganic substances through photosynthesis (by green plants) or chemosynthesis (by anaerobic bacteria) and serves as a source of food in the food chain