Unit Plan 11 (Grade 7 Science): Biotic Interactions
Grade 7 unit where students predict ecosystem patterns—predator–prey cycles, competition, and mutualism—to explain how interactions shape populations and community balance.
Focus: Predict patterns of interaction among organisms in ecosystems, including predator–prey, competition, and mutualism, and explain how these interactions shape populations and community structure.
Grade Level: 7
Subject Area: Science (Life Science — Ecosystems & Interactions)
Total Unit Duration: 5 sessions (one week), 50–60 minutes per session
I. Introduction
In this unit, students explore how organisms interact with one another in ecosystems and how those interactions create predictable patterns. Building on resource availability from the previous unit, they analyze examples of predator–prey relationships, competition within and between species, and mutualism (and related interactions) where both partners benefit. Using food webs, diagrams, and short case studies, students construct explanations aligned to MS-LS2-2 that predict what will happen when one part of an interaction changes.
Essential Questions
- What kinds of biotic interactions (predator–prey, competition, mutualism) occur in ecosystems?
- How do predators and prey affect each other’s population patterns over time?
- How does competition for limited resources shape where organisms live and how many can survive?
- How can we predict what will happen to an ecosystem when one population in an interaction increases, decreases, or disappears?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Define and identify examples of major biotic interactions in ecosystems: predator–prey, competition, and mutualism (and related interactions).
- Use food chains, food webs, and interaction diagrams to describe how organisms are connected through these interactions.
- Analyze short scenarios or simplified data sets to identify patterns in predator–prey cycles, competition outcomes, and mutualistic relationships.
- Construct explanations that predict what will happen to one population when another population in the interaction changes (e.g., increases, decreases, is removed).
- Communicate a written or visual explanation that uses examples and reasoning to show patterns of interactions among organisms, meeting MS-LS2-2.
Standards Alignment — 7th Grade (NGSS-based custom)
- MS-LS2-2 — Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.
- Students explain and predict interactions like predation, competition, and mutualism, and how these affect populations and community structure.
Success Criteria — Student Language
- I can explain what predator–prey, competition, and mutualism mean and give clear examples.
- I can read or draw food webs and interaction diagrams that show how organisms are connected.
- I can describe patterns in how predator and prey populations change together over time.
- I can explain how competition affects where organisms live and how many can survive.
- I can predict what will happen if one population increases, decreases, or disappears, and support my prediction with ecological reasoning.