Biology · Grade 12

Active learning ideas

Interspecific Interactions: Competition and Predation

Active learning works for interspecific interactions because students need to see how small changes in traits or behaviors ripple through food webs. Simulation games and case studies let them test assumptions in real time, turning abstract models like Lotka-Volterra into observable patterns. Movement, collaboration, and immediate feedback make the invisible processes of competition and predation visible and memorable.

• Ontario Curriculum Expectations
• HS-LS2-2

• 30–50 min
• Pairs → Whole Class
• 4 activities

Activity 01

• Simulation Game
• 45 min · Small Groups

Simulation Game: Predator-Prey Cycles

Scatter paper 'prey' on the floor; 'predator' students collect as many as possible in 1 minute, then switch roles for multiple generations. Vary predator numbers and record data. Graph population trends to identify cycles.

How does the loss of a keystone species trigger a trophic cascade?

Facilitation Tip

For the Predator-Prey Cycles simulation, circulate with a timer and call out the next generation loudly so students stay synchronized without constant prompting.

What to look for

Provide students with two species profiles that share a similar food source. Ask them to predict whether competitive exclusion or resource partitioning is more likely to occur, and to justify their answer using specific traits of the species and their environment.

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

Activity 02

• Case Study Analysis
• 50 min · Small Groups

Case Study Analysis: Yellowstone Wolves

Provide data sets and videos on wolf reintroduction effects on elk, vegetation, and beavers. In groups, map the trophic cascade and predict changes if wolves were removed. Share findings in a class jigsaw.

In what ways does niche partitioning reduce competition between overlapping species?

Facilitation Tip

During the Yellowstone Wolves case study, assign roles so each student contributes to the flow diagram while someone else narrates the changes aloud.

What to look for

Pose the question: 'Imagine a new predator is introduced into an ecosystem with established predator-prey cycles. What are two potential consequences for the existing populations and overall community structure?' Facilitate a class discussion where students share their predictions and reasoning.

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

Activity 03

• Placemat Activity
• 30 min · Pairs

Placemat Activity: Resource Partitioning Cards

Distribute cards representing food resources and species traits. Pairs assign traits to niches, first modeling full competition leading to exclusion, then partitioning to show coexistence. Discuss adaptations.

Analyze the co-evolutionary arms race between predators and prey.

Facilitation Tip

When running the Resource Partitioning Cards activity, ask students to swap cards after each round to prevent fixed pairings from skewing their observations.

What to look for

On an index card, have students draw a simple food web showing a keystone species. Then, ask them to draw an arrow indicating the removal of that species and write one sentence describing a likely trophic cascade that would result.

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

Activity 04

• Experiential Learning
• 35 min · Pairs

Graphing: Lynx-Hare Data

Provide historical population graphs. Individually plot new data points from tables, then in pairs analyze cycle phases and predict next peaks. Connect to Lotka-Volterra.

How does the loss of a keystone species trigger a trophic cascade?

Facilitation Tip

In the Graphing Lynx-Hare Data activity, provide colored pencils for each group and require them to label axes and units before plotting to reduce careless errors.

What to look for

Provide students with two species profiles that share a similar food source. Ask them to predict whether competitive exclusion or resource partitioning is more likely to occur, and to justify their answer using specific traits of the species and their environment.

• Apply
• Analyze
• Evaluate
• Self-Awareness
• Self-Management
• Social Awareness

A few notes on teaching this unit

Start with the simplest model first: show students a two-species competition scenario on the board, then let them run the simulation to watch competitive exclusion unfold in minutes, not semesters. Avoid overloading them with equations early; build intuition from observed patterns. Research shows that students grasp keystone species best when they trace effects forward and backward through food webs themselves, rather than just listening to a lecture about them.

Successful learning is shown when students can explain why similar species coexist, trace the causes of population cycles, and predict ecosystem-wide effects when a keystone species is removed. They should use visual models, data, and real-world examples to justify their reasoning, not just recall definitions.

---

Watch Out for These Misconceptions

• During the Resource Partitioning Cards activity, watch for students who assume competition always leads to extinction.

  Ask them to adjust the cards to reduce overlap and observe how coexistence becomes possible; have them calculate the percentage change in shared resources to quantify their adjustments.

• During the Predator-Prey Cycles simulation, watch for students who expect predator numbers to rise and fall exactly with prey numbers in the same generation.

  Pause the simulation after round three to ask groups to sketch predicted values for the next round, then compare their predictions to the actual results to highlight the lag effect.

• During the Yellowstone Wolves case study discussion, watch for students who assume keystone species only affect their direct prey.

  Give each group a colored marker and have them trace arrows from wolves to scavengers, plants, and birds on the flow diagram to reveal indirect effects before sharing out.

---

Methods used in this brief

• Simulation Game
• Case Study Analysis
• Placemat Activity
• Experiential Learning