Note: Teacher’s notes are in red

“Web of Life”

Purpose of This Activity

Students will understand how preserving the species and natural elements of an ecosystem contributes to the sustainability of that ecosystem. In an ecosystem everything, living and inanimate, has a role. When one element is removed—perhaps by erosion, overhunting, habitat destruction, or disease—the effect is felt throughout the system. As more elements are removed the system becomes impoverished.

Your Mission

Become a “Webmeister”! Learn about the real World Wide Web—the web of life that connects all Earth’s living things.

Relevant U.S. National Geography Standards: 1, 6, 7, 8, 14

Materials

• Yarn or string
• Cardboard

The Web’s Ingredients: Ecosystems

Like everything else, the web of life is made up of parts. These parts are called ecosystems. An ecosystem is a community of plants and animals and their physical environment. In an ecosystem, everything has a role. When something is removed, watch out! Read about an ecosystem from a spider’s point of view in “Web of Life” at Kids’ Planet (http://www.kidsplanet.org/wol).

“Web of Life” is narrated by a spider, and will help even young students understand ecosystems. Students can read the story on their own or you can read it aloud.

The Elements of an Ecosystem

The parts of an ecosystem are called elements. Some elements are living things, like plant and animal species. Some elements are nonliving things, like sun, rain, air, water, and soil.

Introducing Your Class to Ecosystems

Choose a habitat common to your region and write its name on the board (e.g., woodland, wetland, desert, meadow). For background information on habitats, see the U.S. Department of Agriculture’s Wildlife Habitat site (http://www.nhq.nrcs.usda.gov/CCS/WildHab.html).

Ask students to name 20 plants or animals that might live in the habitat, and list them on the board. To help students brainstorm, ask them what kinds of animals or plants they might find in their backyard. For some examples, go to the Family of Nature Web sites (http://mgfx.com/bird/backyard.htm).

Remind students to name small plants, reptiles, amphibians, and invertebrates (such as earthworms and beetles), as well as mammals and birds. What else can be found in the ecosystem? Sunlight, water, rocks, soil, air.

Ecosystems Close to Home

List some of the elements in the ecosystem of a habitat in your area. Your teacher will help you with this list, which might include mammals, birds, plants (including trees!), reptiles, and amphibians. Illustrations are optional—but welcome!

Getting the Activity Started

Choose volunteers and have them stand in a circle. Give each a sign labeled with one of the words listed on the board. Give the ball of yarn to the student wearing “soil“ and ask, “What grows in soil?” “Soil” passes the ball of yarn to a student labeled as a plant, such as clover. Ask, “What eats clover?” The clover student should pass the ball of yarn to a rabbit or other grazer. Ask, “What does a rabbit drink and breathe?” Continue until the whole class is linked in a giant web of natural elements—an ecosystem.

Building a Web: It’s Elemental!

Take on a new identity: Find out what it’s like to be an element in an ecosystem.

• Form a circle with your classmates and hold on to the sign your teacher gives you. Each sign will bear the name of an element in the ecosystem. Get ready to carry the ball—a ball of yarn, that is.
• Each of you will be a different element (a tree, water, a deer). Your teacher will start the ball rolling by calling on, say, “rabbit,” and asking a question like “What does a rabbit eat?”
• When your teacher calls your element name, it’s time for you to carry the ball. (When “clover” is called, for example, a student will pass the ball of yarn to the “clover” student while still holding on to the yarn or string.)
• Teacher tip: For fun, you could ask students to make a noise that represents their element when they tug on the yarn.
• Keep passing the ball of yarn till your classroom looks like ... a web!

Breaking the Web

Webs are strong, but they can be broken. What happens to your web if something is removed?

• Stand in your element circle, and, with your teacher’s help, consider certain situations.
• If a dam is built nearby, say, the student who represents water should tug on the yarn. Then each student who feels the original tug should tug on the yarn, and so on. (Another example: If crops are planted too often in the same place and the soil loses its nutrients, the student representing soil should tug the yarn, and all the students who feel that tug should tug the yarn.)
• What happened to the web? Did it become tangled?

Ideas for Teaching

Ask students what happens if the habitat experiences soil erosion. Remove soil from the ecosystem. What happens to the web of life? Have the students suggest various scenarios—an oil spill, air pollution, a devastating virus. What would be the effects?

Don’t be surprised if, at some point during the activity, both you and your students wonder exactly WHO the ball of yarn should be given to. Why might that be? Have humans impacted your region in a negative way, resulting in a missing strand in the habitat and ecosystem?

Optional: Have the class do the activity again, but ask two of the students to stand out of the circle during the activity. What happens to the ecosystem?

See how fragile an ecosystem can be? Of course, when the game is over you can step out of the tangled web of yarn and go back to your seat. But plants and animals can’t.

Mending the Web

Learning about tigers and cheetahs can help students understand how changing an ecosystem—in this case, destroying habitat—can contribute to the endangerment of wild animals. (In addition, tigers face danger from poachers, who sell tiger body parts on the black market to be used as folk medicine.)

The Tiger Information Center Web site (http://www.5tigers.org/index.htm) has a wealth of information and lots of fun things for kids, such as an online quiz and tiger sounds. (Look through the site before you send students to screens other than the “talking tiger.” Some of the information, such as images of slain tigers and information about tigers eating humans, may upset young children.)

For information about cheetahs’ habitat loss, go to the Cheetah Conservation Fund Web site (http://www.cheetah.org). You can introduce young students to cheetahs by having them color their favorite pictures of cheetahs from an online coloring book (http://www.cheetah.org/savannah/coloring-book/index.htm).

Learn more about endangered species of plants and animals and the habitats in which they live. Then tell other people what you’ve learned and how important conservation is.

Other Activities

• As you have seen, all plants and animals need a combination of elements to survive. That’s all plants and animals, no matter how big or strong. In fact, the tiger, one of the world’s most powerful animals, is endangered, chiefly because its habitat has been changed or destroyed. To find out more about this endangered animal, ask a “talking” tiger at the 5 Tigers (http://www.5tigers.org/talkback/habitat.htm) site.
  
  
• Color an endangered animal at the nationalgeographic.com Okavango site (http://www.nationalgeographic.com/
  okavango/color.html) and send it by e-mail to a friend. Tell your friend why you’re concerned about cheetahs, tigers, or another endangered species.
  
  
• Perhaps a local expert could come in and talk to your class about an endangered species—plant or animal—that lives in your region. (Think globally, act locally.) There are even some success stories, such as the bald eagle and the peregrine falcon.
  
  

Students can easily become overwhelmed by the many species that need protection, or discouraged that they can’t “save” every one. Remind them: One person can truly make a difference! Facilitate a class discussion that will enable students to do something meaningful. And don’t forget to e-mail the National Geographic Society to let us know what you’re doing to celebrate Geography Awareness Week!

• As a class, talk with your teacher about what you can do to help endangered species, and to help others become “World Wide Web of Life” meisters!

“Web of Life” activity adapted from the 1996 Geography Awareness Week teacher’s handbook. © 1996 National Geographic Society. Handbook activity adapted, in turn, from “Sharing Nature with Children,” by Joseph Cornell, Dawn Publications, 800 545 7475.

Top

Student Page

© 2000 National Geographic Society. All rights reserved.