Unit Plan 13 (Grade 7 Science): Ecosystem Stability & Change
Grade 7 unit where students use data to argue how physical or biological changes—like drought, pollution, or new species—impact populations and ecosystem stability.
Focus: Construct arguments from evidence about how changes to physical (temperature, rainfall, habitat, pollution) or biological components (new species, disease, population changes) affect organisms and populations in ecosystems.
Grade Level: 7
Subject Area: Science (Life Science — Ecosystems & Stability)
Total Unit Duration: 5 sessions (one week), 50–60 minutes per session
I. Introduction
In this unit, students investigate how ecosystems can be stable for long periods yet still change when physical or biological components are altered. Building on their understanding of resources, biotic interactions, and food webs/energy flow, students examine real and simulated examples of disturbances (drought, pollution, invasive species, disease, population booms/crashes). They analyze data, identify patterns, and construct arguments supported by empirical evidence aligned to MS-LS2-4 about how these changes affect populations and ecosystem stability.
Essential Questions
- What does it mean for an ecosystem to be stable over time, and what kinds of changes can disturb that stability?
- How can changes in physical components (e.g., temperature, rainfall, habitat size, pollution) affect organisms and populations?
- How can changes in biological components (e.g., new species introduced, species removed, disease outbreaks) affect ecosystem interactions and population sizes?
- How do scientists use data and evidence to construct arguments about ecosystem stability and change?
II. Objectives and Standards
Learning Objectives — Students will be able to:
- Define and give examples of ecosystem stability, disturbance, and physical vs. biological components of ecosystems.
- Analyze graphs, tables, case studies, or simulation outputs showing population changes after physical or biological disturbances.
- Identify patterns in how populations respond to different types of changes (e.g., gradual vs. sudden, small vs. large).
- Construct written or oral arguments that clearly state a claim, support it with empirical evidence, and connect it with scientific reasoning about ecosystem interactions.
- Use these arguments to explain how specific changes in physical or biological components affect populations, meeting MS-LS2-4.
Standards Alignment — 7th Grade (NGSS-based custom)
- MS-LS2-4 — Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.
- Students use data and case studies about disturbances (e.g., habitat loss, invasive species, climate shifts) to argue how populations respond.
Success Criteria — Student Language
- I can explain what ecosystem stability and disturbance mean and give examples of physical and biological changes.
- I can read graphs/tables/case studies to see how populations change after a disturbance.
- I can describe patterns in how populations respond to changes (e.g., decline, recovery, new stable level).
- I can write or present an argument with a clear claim, evidence from data, and reasoning that connects the evidence to my claim.
- I can use scientific vocabulary (e.g., population, resource, interaction, disturbance, stability) to explain ecosystem changes.