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Objective: To explore the ecological changes brought about by the reintroduction of wolves into the Greater Yellowstone Ecosystem and understand the concept of a trophic cascade.
Grade Level: Middle School (6th - 8th Grade)
Duration: 2 class periods
Materials Needed:
Access to the internet for research
Maps or diagrams of Yellowstone National Park
Writing materials
A projector for presentations
Lesson 1: Introduction to the Yellowstone Wolf Reintroduction (45 minutes)
Step 1: Introduction (10 minutes)
Begin by discussing the importance of Yellowstone National Park as a unique ecosystem.
Explain that in 1995, gray wolves were reintroduced to the park, and this event had a significant impact on the ecosystem.
Pose the central question: "How did the reintroduction of wolves change the Yellowstone ecosystem?"
Step 2: Watch a Video (15 minutes)
Show a short video (e.g., a documentary clip or educational video) about the Yellowstone Wolf Reintroduction. https://www.youtube.com/watch?v=gc52l5ZcAJ0
Discuss with students what they observed in the video and what changes they think wolves may have brought to the ecosystem.
Step 3: Research and Discussion (20 minutes)
In small groups, ask students to research and discuss the following questions:
How did the presence of wolves affect the elk population in Yellowstone?
What role did beavers play in this ecosystem and how did their population change?
How did the presence of wolves influence vegetation in the park?
Have each group share their findings with the class.
Homework (optional): Assign students to write a short paragraph summarizing what they learned about the Yellowstone Wolf Reintroduction.
Lesson 2: Exploring the Trophic Cascade (45 minutes)
Step 1: Review (10 minutes)
Begin by reviewing the key points from the previous lesson, particularly the impact of wolves on elk, beavers, and vegetation.
Step 2: Trophic Cascade Discussion (15 minutes)
Explain the concept of a "trophic cascade" as a chain reaction of ecological changes triggered by the introduction or removal of a species.
Discuss the idea that wolves, as top predators, can have far-reaching effects on an ecosystem.
Step 3: Group Activity (15 minutes)
Divide the class into small groups and provide them with a trophic cascade diagram template.
In their groups, students should create a trophic cascade diagram that illustrates the impact of wolves on the Yellowstone ecosystem, including elk, beavers, vegetation, and other species.
Encourage creativity in their diagrams, using arrows, pictures, and labels to represent the connections.
Step 4: Group Presentations (5 minutes per group)
Each group presents their trophic cascade diagram to the class, explaining the cause-and-effect relationships they've depicted.
Homework: Ask students to reflect on how this ecological concept could apply to other ecosystems and research a trophic cascade in a different habitat.
Assessment: Review the group presentations and the homework assignments to assess the students' understanding of the Yellowstone Wolf Reintroduction and the concept of a trophic cascade.