Note: Teachers 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 removedperhaps by erosion, overhunting, habitat destruction, or diseasethe effect is felt throughout the system. As more elements are removed the system becomes impoverished.
Become a Webmeister! Learn about the real World Wide Webthe web of life that connects all Earths living things.
Relevant U.S. National Geography Standards: 1, 6, 7, 8, 14
The Webs 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 spiders 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 Agricultures 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 optionalbut 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 elementsan ecosystem.
Building a Web: Its Elemental!
Take on a new identity: Find out what its 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 balla 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, its 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 teachers 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 scenariosan oil spill, air pollution, a devastating virus. What would be the effects?
Dont 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 cant.
Mending the Web
Learning about tigers and cheetahs can help students understand how changing an ecosystemin this case, destroying habitatcan 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 youve learned and how important conservation is.
- As you have seen, all plants and animals need a combination of elements to survive. Thats all plants and animals, no matter how big or strong. In fact, the tiger, one of the worlds 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 youre concerned about cheetahs, tigers, or another endangered species.
- Perhaps a local expert could come in and talk to your class about an endangered speciesplant or animalthat 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 cant 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 dont forget to e-mail the National Geographic Society to let us know what youre 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 teachers handbook. © 1996 National Geographic Society. Handbook activity adapted, in turn, from Sharing Nature with Children, by Joseph Cornell, Dawn Publications, 800 545 7475.
© 2000 National Geographic Society. All rights reserved.