Science · 7th Grade

Active learning ideas

Ecosystem Change and Stability

Dive into the dynamic world of ecosystems to discover why some can weather a storm while others fall apart.

• Common Core State Standards
• NGSS: MS-LS2 - Ecosystems: Interactions, Energy, and Dynamics - Constructing an Argument about how Changes to Physical or Biological Components Affect Populations

• 25–120 min
• Pairs → Whole Class
• 3 activities

Activity 01

• Case Study Analysis
• 25 min · Small Groups

Biodiversity Jenga

Use a Jenga tower to represent an ecosystem, with each block symbolizing a species. Students take turns removing blocks, representing species loss, and observe how the tower's stability decreases, demonstrating that more diverse ecosystems (fuller towers) are more stable.

Analyze the factors that contribute to an ecosystem's resilience after a forest fire.

Facilitation Tip

Assign different colors to blocks to represent producers, primary consumers, and secondary consumers to add another layer of complexity.

What to look for

Use an exit ticket asking students to predict three effects of removing a specific producer from a given food web.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 02

• Case Study Analysis
• 90 min · Small Groups

Ecosystem Disturbance Case Studies

In small groups, students research a specific environmental event, such as the reintroduction of wolves to Yellowstone or the impact of zebra mussels in the Great Lakes. They present their findings on the causes, the effects on the ecosystem's stability, and the response.

Explain the process of ecological succession on a newly formed volcanic island.

Facilitation Tip

Provide a graphic organizer to help students structure their research on biotic, abiotic, and human-caused factors.

What to look for

Students research a real-world ecosystem disturbance and create a presentation or report. They must identify the cause, analyze the impact on biodiversity and stability, and propose a scientifically-sound restoration plan.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

Activity 03

• Case Study Analysis
• 120 min · Pairs

Succession in a Jar

Students create a simple aquatic ecosystem in a sealed jar with pond water, sand, and a few aquatic plants. They observe the changes over several weeks, noting how the community of microorganisms and plants develops and changes over time, modeling ecological succession.

Evaluate how a loss of biodiversity might affect an ecosystem's ability to withstand environmental changes.

Facilitation Tip

Have students maintain a detailed observation log with drawings and written descriptions to track the changes.

What to look for

Students complete a K-W-L (Know, Want to Know, Learned) chart at the beginning and end of the unit to reflect on their learning journey and identify remaining questions.

• Analyze
• Evaluate
• Create
• Decision-Making
• Self-Management

A few notes on teaching this unit

Start by grounding the concepts of stability and change in a familiar, local ecosystem like a park or pond. Use hands-on models like the 'Biodiversity Jenga' activity to make abstract concepts like stability tangible. Then, transition to analyzing real-world case studies to apply their understanding to complex, authentic problems.

Your students will be able to analyze the factors that make an ecosystem stable and argue from evidence how disturbances can tip the balance.

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Watch Out for These Misconceptions

• Ecosystems are static and unchanging.

  Ecosystems are dynamic and are constantly changing. Stability does not mean a lack of change, but rather the ability to resist or recover from disturbances through processes like ecological succession.

• All environmental changes are harmful to an ecosystem.

  Some disturbances, like seasonal flooding in floodplains or natural fires in certain forests, are a necessary part of the ecosystem's cycle. These events can clear out old growth, release nutrients into the soil, and create opportunities for new species to thrive.

• The loss of one species doesn't really matter in a large ecosystem.

  The loss of a single keystone species, like a top predator or a critical pollinator, can trigger a trophic cascade, causing drastic changes throughout the entire food web and potentially leading to the ecosystem's collapse.

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Methods used in this brief

• Case Study Analysis