Community Interactions: Competition & Predation

Active learning works for this topic because students must experience the mechanisms of competition and predation to grasp their effects. Simulations and role-plays create a visceral understanding of resource limits and population dynamics that lectures cannot replicate.

• Grade 9
• Science
• 4 activities
• 30 min–50 min

Learning Objectives

1. Analyze how interspecific competition influences the distribution and abundance of species within a given habitat.
2. Predict the population dynamics of a prey species following the introduction of a novel predator.
3. Compare and contrast the outcomes of competitive exclusion and resource partitioning in stable ecosystems.
4. Evaluate the impact of invasive species on native community interactions, specifically competition and predation.
5. Explain the mechanisms by which predation regulates prey populations in Canadian ecosystems.

Simulation Game

⏱ 45 min·Pairs

Simulation Game: Predator-Prey Bean Hunt

Scatter green beans (prey) and red lentils (predators) on the floor. Pairs act as predators collecting prey in 1-minute rounds, recording captures. Over 10 rounds, graph population trends to observe cycles. Discuss factors like predator efficiency.

Prepare & details

Analyze how interspecific competition can lead to resource partitioning.

Facilitation Tip: When introducing an invasive predator, assign roles so students simulate both the predator's impact and the prey's responses over multiple generations.

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

Case Study Analysis

⏱ 35 min·Small Groups

Role-Play: Resource Partitioning

Assign small groups species roles competing for paper resources (food, space). Introduce scarcity, then guide partitioning strategies like time or location shifts. Groups present adaptations and vote on survival likelihood.

Prepare & details

Predict the long-term effects of introducing a new predator into an ecosystem.

Setup: Groups at tables with case materials

Materials: Case study packet (3-5 pages), Analysis framework worksheet, Presentation template

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

Stations Rotation

⏱ 50 min·Small Groups

Stations Rotation: Competition Scenarios

Set up stations with models: exclusion (one species dominates), partitioning (shared niches), predation webs. Groups rotate, predict outcomes, and adjust variables like resource levels. Compile class data for patterns.

Prepare & details

Differentiate between competitive exclusion and resource partitioning.

Setup: Tables/desks arranged in 4-6 distinct stations around room

Materials: Station instruction cards, Different materials per station, Rotation timer

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

Case Study Analysis

⏱ 30 min·Whole Class

Invasive Predator Introduction

Use whole class as ecosystem; introduce 'invasive' volunteers as new predators. Track prey decline over rounds with counters. Debrief long-term effects and stewardship solutions.

Prepare & details

Analyze how interspecific competition can lead to resource partitioning.

Setup: Groups at tables with case materials

Materials: Case study packet (3-5 pages), Analysis framework worksheet, Presentation template

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

Teaching This Topic

Teachers should emphasize that competition and predation are not one-sided but dynamic interactions. Avoid framing these relationships as purely destructive; instead, highlight how they drive adaptation and ecosystem stability. Research shows students retain concepts better when they see immediate cause-and-effect in simulations.

What to Expect

Successful learning looks like students explaining how competition leads to coexistence or exclusion, and how predation creates population cycles. They should connect these concepts to ecosystem balance and cite evidence from their activities.

Watch Out for These Misconceptions

Common Misconception

During the Role-Play: Resource Partitioning activity, watch for students assuming the strongest or most aggressive species will always win.

What to Teach Instead

Use the role-play’s resource zones to redirect students: have them adjust behaviors or timing to demonstrate that partitioning allows coexistence, and collect their data sheets to highlight successful strategies.

Common Misconception

During the Simulation: Predator-Prey Bean Hunt activity, watch for students believing predators will always eliminate prey populations.

What to Teach Instead

After each round, pause the simulation to graph predator and prey numbers, then ask students to predict the next cycle and explain why prey rebound—use their graphs to correct the misconception with evidence.

Common Misconception

During the Station Rotation: Competition Scenarios activity, watch for students assuming competition only happens between species that look alike.

What to Teach Instead

Provide station cards showing diverse species (e.g., birds and insects sharing nectar) and ask students to identify the shared resource, then discuss how similar-looking species might avoid competition through timing or feeding habits.

Assessment Ideas

Quick Check

After the Station Rotation: Competition Scenarios, present students with a scenario describing two species in a habitat with a shared food source. Ask them to identify the type of interaction and predict whether competitive exclusion or resource partitioning is more likely, justifying their answer using evidence from their station work.

Discussion Prompt

After the Invasive Predator Introduction activity, facilitate a class discussion using the prompt: 'Imagine a new bird species is introduced to an area with established insectivorous birds. What are two ways this new species could impact the native bird populations, and what evidence would you look for to support your predictions?' Evaluate responses for understanding of niche overlap and evidence-based reasoning.

Exit Ticket

During the Predator-Prey Bean Hunt simulation, provide students with a diagram of a simple food web. Ask them to circle one predator-prey relationship and one competitive relationship, then write one sentence explaining how removing the predator would affect the prey population, using terms from the simulation.

Extensions & Scaffolding

• Challenge students to design an experiment testing how changing resource abundance affects competitive outcomes, then collect class data to analyze trends.
• For students who struggle, provide pre-labeled diagrams of shared resources and ask them to identify which behaviors reduce competition.
• Deeper exploration: Assign students to research a real-world case of invasive species and present how predation or competition disrupted the ecosystem, connecting it to the simulation findings.

Key Vocabulary

Interspecific Competition	A type of interaction where individuals of different species compete for the same limited resources, such as food, water, or territory.
Resource Partitioning	The division of limited resources by species that coexist, allowing them to use the same resources in a different way or at a different time to reduce competition.
Competitive Exclusion	The principle that two species competing for the exact same limiting resources cannot coexist indefinitely; one species will eventually outcompete and eliminate the other.
Predation	An interaction where one organism, the predator, hunts and kills another organism, the prey, for food.
Niche	The role and position a species has in its environment, including how it meets its needs for food and shelter, how it survives, and how it reproduces.