Students simulate a food web using yarn and organism cards to demonstrate ecosystem interdependence. The activity highlights the effects of species extinction on the balance of an ecosystem.

1. Prepare a food web diagram for an endangered species ecosystem.
2. Write the names of organisms from the food web onto index cards. Duplicate lower-level species like plants and insects to represent their abundance.
3. Distribute one card per student. Each student introduces their organism and its role in the ecosystem.
4. Give the student with the endangered species card a ball of yarn. They hold one end and toss the yarn to another student while explaining the connection between their organisms.
5. Each recipient keeps hold of the yarn and tosses the ball to another student, explaining connections, until all students are linked.
6. Once the web is complete, point out its complexity and connections.
7. Simulate extinction by cutting the yarn of the endangered species. Discuss how the network collapses and which organisms are most affected.
8. Encourage predictions about secondary effects, such as prey overpopulation or predator starvation.

Food Webbing Activity - Carol G Cummings:

📄 An Interactive Food Web Game for the Classroom - ThoughtCo: https://www.thoughtco.com/interactive-food-web-game-1182042

• Use different ecosystems (marine, forest, desert) to compare complexity of food webs.
• Assign multiple endangered species and compare impacts when different links are removed.
• Extend the game by introducing “environmental changes” (pollution, habitat loss) and cutting additional yarn strands.
• Combine with digital food web diagrams for added visual learning.

• Ensure students remain seated or in a clear area while tossing yarn to prevent tripping.
• Supervise younger students when handling scissors and yarn.

• What happens to the food web when one species goes extinct? (Connections break, and dependent species may decline or collapse.)
• Why are lower-level species often duplicated in the game? (They are more numerous and support many higher-level organisms.)
• How does the loss of a predator affect the population of prey? (Prey populations may increase, potentially leading to resource depletion.)
• Why is it important to study food webs when protecting endangered species? (Conservation must consider all ecosystem relationships, not just the target species.)
• How does this activity model real-world ecological interdependence? (It shows that all species are linked, and disruptions affect the entire system.)