7-12, Unit Two, Activity 5: "Subalpine Web"

The classic “Ball of yarn” web activity, combined with a “Who am I?” quiz game – about the alpine and subalpine prime-time players.

Grades: 7 – 12
Time: 1 hour
Subjects: Life science, social science / economics


  • Photocopies of “Who am I?” cards (1 of each for class < 25, two of each for class > 25) – please note that the copies should be 2-sided and laminated for durability
  • Fold each card and attach a ‘neck loop” of yarn to the fold area (about 3 feet long)
  • Large ball of yarn (softball sized or larger) or string
  • Roll of toilet paper

1. The “Who am I?” cards should be made so that the student can read the description of the subalpine "citizen" on their card to the other students, with the picture of the animal, plant, geologic feature, etc. hidden from view.

2. The cards should be copied from the link in the materials section above and folded so that the photo is on the inside.

3. Use the same number of cards as students in your class. The cards are arranged in the approximate order of importance to the “web,” so be sure to use the first few cards in this game.

4. Write the names of all the subalpine "citizens" on the board or supply the list to students another way.

5. Distribute the cards to students without letting them see who they are (plain-side up).

6. Have them stand or sit in a tight circle and play the “Who am I?” game, using the list of "citizens" for reference.

7. Have them go one at a time and read one sentence from their card. Then they should wait for the group to guess their “identity” after each descriptive sentence. Encourage the person whose turn it is, to share anything else they know about the "citizen" in question.

8. Once the identity has been discovered, the student flips open the card to show the name and picture of their "citizen."

9. After everyone has had a turn, pick a student at random and give them the ball of yarn. They should look at all of the cards and choose one that the "citizen" on their card may need, under any circumstances, directly or indirectly. They then toss the ball to the "citizen" they need, but keep holding the end of the yarn.

10. Before they toss the yarn, they must explain the ways they need the "citizen" they are about to toss the yarn to. (You may want to carry the ball yourself if necessary.)

11. Every time the ball is tossed, the receiving “citizen” repeats the process, holding the end of yarn they just received.

12. At first, have them try to include every person by explaining their relationships and tossing to someone who has yet to be included. The receiving person tightens the yarn connection before proceeding. Have them continue to weave the web until all the connections are included for each citizen. (It is conceivable that every person could be connected to everyone else if the students are astute about indirect connections.)

13. Is there anyone in the web who you think is especially important? Why? If a human were included in the web, would anyone need them? Who? Why?

14. Holding the end of the toilet paper. Toss the roll across the middle of the web, and announce that this is the International Border between Canada and the United States. Does the border make any difference in the web? How could this web affect you?

15. Announce that it is 1910, and white pine blister rust has been introduced. Have the whitebark pine drop all of its yarn. Then have all those who directly depend on whitebark pine seeds to drop their yarn.

16. Continue the process. Discuss what happened. Explain what a "keystone" species is. Relate the meaning of "keystone species" back to the web and inter-relationships.

Extensions and Variations:
Can students think of other species that could be considered "keystone" to their communities (ex. alligators in Florida Everglades)? Have them use the internet to find out about other "keystones."

Who is affected most by the decline of whitebark pine? Why? Is anyone in the web not affected? Why could you call whitebark pine a “keystone” species? What do you think we could do to help undo the whitebark’s decline? Have students do a journal entry of the web, using a string of words summarizing each relationship to replace the “yarn”.

Last updated: November 8, 2017

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