Ecological Succession and Disturbance

Ecological succession is a dynamic process that benefits from active, visual learning because students often struggle to connect abstract timelines with real-world changes. Hands-on activities like sequencing photos or running simulations make abstract concepts such as pioneer species and soil formation concrete and memorable.

• 9th Grade
• Biology
• 4 activities
• 25 min–45 min

Learning Objectives

1. Compare and contrast primary and secondary ecological succession, identifying key differences in starting conditions and initial colonizers.
2. Explain the role of pioneer species in facilitating the establishment of later successional species by altering environmental factors.
3. Analyze case studies of ecological disturbances, such as Mount St. Helens or Yellowstone fires, to trace the stages of succession over time.
4. Critique the traditional concept of a climax community by evaluating evidence of ongoing disturbance and ecosystem dynamism.

Timeline Challenge

⏱ 40 min·Small Groups

Photo Sequencing: Succession Timeline

Small groups receive 8 to 10 photographs taken at different times after a specific disturbance (Mount St. Helens volcano sites or Yellowstone post-1988 fire areas). Students arrange the photos in chronological order, justify the sequence using ecological logic, and label each photo with the dominant functional group and its role in facilitating the next stage.

Prepare & details

Differentiate between primary and secondary succession.

Facilitation Tip: During Photo Sequencing, circulate and ask students to justify their ordering by pointing to visual evidence of soil formation or species presence in each image.

Setup: Long wall or floor space for timeline construction

Materials: Event cards with dates and descriptions, Timeline base (tape or long paper), Connection arrows/string, Debate prompt cards

• Remember
• Understand
• Analyze
• Self-Management
• Relationship Skills

Simulation Game

⏱ 45 min·Small Groups

Simulation Game: Succession Dice Game

Students represent different plant species with specific colonization, growth, and displacement rules encoded on cards. Each round, dice rolls determine whether each species establishes, grows, or is displaced. The class tracks community composition over 20 rounds, graphs the proportional representation of each species, and identifies the successional trajectory that emerges.

Prepare & details

Explain how pioneer species modify the environment for later arrivals.

Facilitation Tip: For the Succession Dice Game, model fair play and timekeeping to ensure all groups experience the probabilistic nature of species replacement.

Setup: Flexible space for group stations

Materials: Role cards with goals/resources, Game currency or tokens, Round tracker

• Apply
• Analyze
• Evaluate
• Create
• Social Awareness
• Decision-Making

Timeline Challenge

⏱ 40 min·Small Groups

Collaborative Debate: Is the Climax Community Concept Accurate?

Students read two short competing passages: one presenting the classical climax community model and one presenting the modern non-equilibrium disturbance perspective. Small groups create a two-column evidence chart, then participate in a structured class discussion to develop a nuanced position on whether 'climax community' is a useful scientific concept.

Prepare & details

Critique the concept of a 'climax community' in light of ongoing environmental change.

Facilitation Tip: In the Climax Community Debate, assign roles to students before the activity to ensure balanced participation and structured argumentation.

Setup: Long wall or floor space for timeline construction

Materials: Event cards with dates and descriptions, Timeline base (tape or long paper), Connection arrows/string, Debate prompt cards

• Remember
• Understand
• Analyze
• Self-Management
• Relationship Skills

Think-Pair-Share

⏱ 25 min·Pairs

Think-Pair-Share: Classifying Succession Types

Students receive six disturbance scenarios (volcanic eruption, forest fire, glacier retreat, agricultural abandonment, hurricane, quarry abandonment) and classify each as primary or secondary succession. They compare predictions with a partner, resolve differences by applying the soil criterion, and then predict the first three functional groups to colonize each site.

Prepare & details

Differentiate between primary and secondary succession.

Setup: Standard classroom seating; students turn to a neighbor

Materials: Discussion prompt (projected or printed), Optional: recording sheet for pairs

• Understand
• Apply
• Analyze
• Self-Awareness
• Relationship Skills

Teaching This Topic

Teachers should emphasize that succession is directional but not rigid, and avoid reinforcing the idea of a single, permanent climax community. Research suggests students grasp succession better when they trace cause-and-effect chains, such as how lichens break down rock to form soil, which then supports mosses and grasses. Use frequent formative checks to correct misconceptions early, especially about pioneer species and soil development.

What to Expect

Students will articulate the differences between primary and secondary succession, explain how pioneer species alter the environment, and evaluate the concept of climax communities with supporting evidence. Success looks like students using specific terms correctly in discussions and applying their knowledge to novel scenarios.

Watch Out for These Misconceptions

Common Misconception

During Photo Sequencing, watch for students assuming all succession ends in a forest.

What to Teach Instead

During Photo Sequencing, include images of climax communities from different US biomes (e.g., grassland, desert) and ask students to describe how climate shapes the endpoint of succession based on these visuals.

Common Misconception

During the Succession Dice Game, students may expect primary succession to happen faster because 'new' sounds easier.

What to Teach Instead

During the Succession Dice Game, explicitly compare the time scales for primary succession (e.g., 100 years per roll) and secondary succession (e.g., 10 years per roll) on the game board to highlight why secondary succession is typically faster.

Common Misconception

During the Think-Pair-Share activity, students might believe pioneer species destroy their habitat by making it unsuitable for themselves.

What to Teach Instead

During Think-Pair-Share, have students trace the mechanism of soil enrichment and nitrogen fixation by pioneer species, then link this to the competitive advantages of later species, using a provided case study on lichen and moss colonization.

Assessment Ideas

Quick Check

After the Think-Pair-Share activity, present students with two scenarios: one describing colonization of a new lava flow, the other an abandoned farm field. Ask students to write one sentence identifying which is primary succession and one sentence identifying which is secondary succession, and why.

Discussion Prompt

During the Collaborative Debate on climax communities, facilitate a class discussion where students cite examples of ongoing disturbances and ecosystem resilience to support their arguments, focusing on evidence from the debate materials.

Exit Ticket

After the Photo Sequencing activity, provide students with images depicting different stages of plant growth on a bare rock surface. Ask them to label the images in the correct order of primary succession and identify one pioneer species that might be present in the earliest stage.

Extensions & Scaffolding

• Challenge students to create a 3-minute podcast explaining how a specific disturbance (e.g., hurricane, volcanic eruption) alters succession in a given biome.
• Scaffolding: Provide a word bank and partially completed timeline for students who struggle during Photo Sequencing.
• Deeper exploration: Have students research and present on how human activities (e.g., urbanization, reforestation) influence or mimic natural succession.

Key Vocabulary

Ecological Succession	The gradual process by which ecosystems change and develop over time, involving predictable shifts in species composition.
Primary Succession	Ecological change that begins on surfaces devoid of soil and life, such as newly formed volcanic rock or glacial till.
Secondary Succession	Ecological change that occurs in areas where a community previously existed but has been disturbed, leaving soil intact.
Pioneer Species	The first organisms, typically hardy plants like lichens and mosses, to colonize barren land and initiate ecological succession.
Climax Community	A theoretical stable, mature ecological community that represents the final stage of succession for a given environment.