When studying an endangered species, scientists must learn about more than just one rare animal. They have to consider the animal's entire food web in order to help protect it from the threat of extinction.
In this classroom challenge, student scientists work together to simulate an endangered food web. By assuming the roles of linked organisms in an ecosystem, kids will actively observe interdependence and explore the repercussions of breaking vital links.
Write the names of organisms from a food web diagram on note cards. If there are more students in the class than species, duplicate lower level species (there are generally more plants, insects, fungi, bacteria, and small animals in an ecosystem than large animals). Endangered species are assigned only one card each.
Each student draws one organism card. Students announce their organisms to the class and discuss the roles they play within the ecosystem.
One student with an endangered species card holds a ball of yarn. Using the food web diagram as a guide, this student will hold the end of the yarn and toss the ball to a classmate, explaining how the two organisms interact.
The recipient of the ball will keep hold of the yarn strand and toss the ball to another student, explaining their connection. The yarn toss will continue until every student in the circle is holding at least one strand of yarn.
When all organisms are connected, observe the complex "web" that has been formed by the yarn. Are there even more connections than students expected?
Single out the endangered species (or the most critically endangered if there are more than one), and cut the yarn strand(s) that are being held by that student. This represents extinction. The species has been removed from the ecosystem forever.
Discuss how the web collapses when the yarn is cut, and identify which species appear to be most affected. Speculate about what might happen to other species in the web when one organism goes extinct. For example, if the extinct animal was a predator, its prey may become overpopulated and deplete other organisms in the web. If the extinct animal was a prey species, then predators that relied on it for food may also go extinct.
Grade Level: 4 to 6 (ages 9 to 12)
Be ready to look up different species on the internet or in textbooks to answer questions about an organism's role in the ecosystem.
Offer a large-sized food web diagram that all students can see (such as an overhead projector image), or pass out one food web diagram to each student for reference during the challenge.
What You Need
- Food web diagram for an endangered species (See examples in "Tips" section.)
- Index cards
- Marker or pen
- Ball of yarn