Ecosystem Interactions

Overview

This 45-minute lesson is Lesson 4 in the 6-lesson unit "Exploring Science Connections" for Grade 7 students following the British Columbia Science Curriculum. Students will examine how organisms interact within ecosystems, focusing on food chains, food webs, and the effects of environmental changes on these interactions.

The lesson aligns with BC's Science 7 curriculum, emphasizing the Life Sciences big idea:

"Relationships exist between biotic and abiotic components in ecosystems."

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Curriculum Alignment

Prescribed Learning Outcomes (PLOs)

• SCI7-2: Describe the structure of an ecosystem and explain how changes in environmental conditions can affect populations and biodiversity.
• SCI7-6: Demonstrate an understanding of the relationships between organisms within ecosystems, including predator-prey, symbiosis, and competition.
• SCI7-7: Use evidence to explain how human activity influences the balance of ecosystems.

Big Ideas addressed

• Interactions within an ecosystem influence the abundance and distribution of organisms.
• Balanced interactions support ecosystem stability; disturbances can lead to shifts in ecosystem structure.

Curricular Competencies

Students will:

• Question and predict to develop hypotheses about ecosystem interactions.
• Plan and conduct collaborative investigations and interpret the evidence collected.
• Connect scientific ideas to interpret the results of changes within food webs.
• Communicate scientific understanding clearly using appropriate terminology.

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Learning Objectives

By the end of this lesson, students will be able to:

1. Illustrate a food chain and expand it into a food web using local ecosystem examples.
2. Explain how different types of species interactions (predation, mutualism, competition) affect ecosystem stability.
3. Analyse the potential impacts of environmental changes (natural or human-caused) on organism populations within a food web.
4. Use scientific terminology such as producer, consumer, predator, prey, decomposer, and biodiversity accurately.

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Materials Required

• Whiteboard and markers
• Projector and computer with a pre-prepared interactive food web diagram
• Printable worksheets with partially completed food webs for annotation
• Card sets (organism cards labelled with BIOTIC/ABIOTIC and organism type)
• Sticky notes
• Poster paper and coloured markers (for group activity)

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Lesson Breakdown

Time	Activity	Description	Assessment
0-5 min	Engage: Phenomenon Introduction	Show an intriguing, brief video clip (~2 minutes) depicting a rapidly changing ecosystem scene (e.g., forest after wildfire or river pollution). Pose questions: "What do you think will happen to animals and plants? How will the change affect their relationships?"	Informal questioning; observes student curiosity and prior knowledge
5-15 min	Explore: Constructing a Food Chain & Food Web	Using an interactive diagram projected, review basic food chain components: producers, consumers, decomposers. Facilitate whole-class co-construction of a simple food chain (e.g., grass -> rabbit -> fox). Then expand to a food web adding more organisms and multiple links.	Students contribute orally; teacher notes accurate use of terms and conceptual understanding
15-25 min	Explain: Types of Interactions	Teacher-led mini-lecture explaining predation, competition, mutualism, parasitism with examples. Use the organism cards to physically demonstrate interactions (e.g., “This rabbit and this deer compete for grass”), moving cards on a table.	Quick quiz-style oral questioning: "Is this interaction predation or mutualism?"
25-35 min	Elaborate: Group Activity – Environmental Change Impact	Divide students into groups of 3. Each group receives a food web worksheet with a local ecosystem example. They select one environmental change (e.g., drought, invasive species, pollution) and predict how it will disrupt the food web. Groups sketch or annotate changes onto their worksheet.	Group presentations; teacher uses a rubric focusing on understanding the cause-effect in food webs and communication skills.
35-43 min	Evaluate: Class Discussion & Reflection	Groups present their findings briefly. Open discussion on how interdependence creates ecosystem balance and how disturbances might cascade. Teacher prompts critical thinking: "How can humans reduce negative impacts?" Conclude with students writing a 1-2 sentence reflection on what surprised them about ecosystem interactions.	Teacher collects reflections to informally assess conceptual grasp and engagement.
43-45 min	Closure & Homework Assignment	Summarise key points verbally. Assign students to observe a nearby park, garden, or backyard to identify at least one food chain or species interaction for discussion in Lesson 5.	Homework serves to connect learning to real-world observations and prepares for next lesson.

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Differentiation Strategies

• Provide sentence starters for written reflections and group presentations for students needing language support.
• Use visual organism cards and diagrams for English Language Learners and students with special needs.
• Challenge advanced students by asking them to hypothesize multi-step consequences in food webs or introduce real-world case studies.
• Allow group roles to accommodate different strengths (scribe, presenter, researcher).

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Cross-Curricular Connections

• English Language Arts: Developing communication skills through group presentations and written reflections.
• Social Studies / Indigenous Perspectives: Briefly integrate traditional Indigenous knowledge about local ecosystems and human-environment relationships as a point for discussion.

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Assessment Criteria

• Accurate use of scientific terminology in oral and written work.
• Demonstrated understanding of food chains, food webs, and species interactions.
• Ability to predict and explain effects of environmental changes on ecosystems.
• Engagement and cooperation during collaborative tasks.

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Teacher Reflection Notes (for after the lesson)

• Did students demonstrate the ability to connect ecosystem components?
• Which misconceptions about food webs or interactions surfaced?
• Were the group activities effective in engaging all learners?
• How did students respond to real-world environmental change discussions?
• Use these reflections to tailor Lessons 5 and 6 with deeper application or remediation as needed.

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This lesson plan delivers a dynamic, evidence-based engagement with ecosystem interactions tailored to BC's Science 7 standards, designed to foster inquiry, collaboration, and critical scientific thinking.