Rocky Shore Ecology

Overview

Subject: Science
Level: NCEA Level 2 (Year 12)
Curriculum Strand: Living World – Ecology (Biological Ideas and Investigating in Science)
Lesson Duration: 45 Minutes
Class Size: 10 Students
Lesson Type: Low-energy, reflective and analytical

Key Learning Outcome:
Students will consolidate their understanding of how biotic factors — specifically interspecific competition, food availability, and predation — affect organisms on New Zealand’s rocky shores. They will apply critical thinking to ecological interactions in a local context.

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Learning Objectives

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

• Describe and give examples of biotic factors that influence population dynamics on the rocky shore
• Analyse ecological relationships using a local case study
• Reflect on and discuss the interconnectedness of species within the ecosystem
• Begin to apply scientific language to ecological scenarios

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Resources Required

• Printed A4 diagrams of a generic NZ rocky shore ecosystem (labelled and unlabelled)
• Clipboards and pens
• Sticky notes or small slips of paper
• Printed cards with organism profiles (e.g., pāua, starfish, mussels, kina, various algae species, predatory snails)
• “What if?” scenario cards (e.g., “Sudden drop in mussel population,” “Increase in kina predators”)
• Whiteboard and markers
• Optional calming background audio: ambient ocean sounds (optional and at teacher discretion)

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Lesson Breakdown

🕐 0–5 min – Settling and Recap

Activity: Seated Circle Discussion
Students sit in a loose circle and briefly recall key ideas from yesterday’s lesson. Prompt with:

• “What’s one biotic factor we discussed?”
• “Can you name an interspecific competition we explored?”
• “Who remembers a predator-prey relationship from yesterday?”

Teacher Tip: Keep answers snappy and light to maintain low energy but solidify recall.

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🕐 5–15 min – "Species Story" Visual Task

Activity: Rocky Shore Ecosystem Match-up (Collaborative, low-motion)
Distribute organism profile cards and unlabelled rocky shore diagrams. Students will work in pairs to place their organism on the correct part of the shore. Encourage them to recall who their organism ‘interacts’ with (competitors, food source, predators).

Curriculum Link: Understanding the impact of interspecific competition and other biotic factors as part of ecological interactions (NCEA Level 2 – Ecology AS91158).

Ask guiding questions:

• “Who does your organism compete with for space or food?”
• “What happens if its food source disappears?”

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🕐 15–25 min – Group “Ecosystem Jenga” (Discussion-Based)

Students form groups of three and pull a “What if?” scenario card.

Examples:

• Removal of top predator
• Increase in algal growth due to nutrient run-off
• Human over-harvesting of pāua

Groups mentally model what will happen to the rest of the ecosystem. They place sticky notes on the diagram showing predicted changes — use arrows and short notes.

They then briefly explain their scenario and thinking to the class.

Key Competency Integration: Thinking – Critical and systems thinking about ecosystem stability and change

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🕐 25–35 min – Reflection & Connect to Local Context

Activity: Silent Write & Share
Pose the question:

“How would a change in just one species affect an entire community on the rocky shore?”

Students write a paragraph response in silence (low-energy), using examples from the previous task. They then share in pairs.

Curriculum Thinking Strategy: Linking scientific theory to local New Zealand ecological examples (such as the impacts of kina barrens in coastal areas like Leigh or depletion of mussels in the Hauraki Gulf).

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🕐 35–43 min – Group Debrief

Bring the class back together. On the board, draw a simple food web based on students’ feedback. As students suggest interconnections, draw arrows and add annotations that specify competition, food sources, and predation.

“What trophic level is under most pressure?”
“What species seem key to ecosystem balance?”

Distil ecological vocabulary as it comes up: niche, trophic level, interdependence, competition, predator-prey dynamics

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🕐 43–45 min – Exit Card

Hand each student a post-it note with this prompt:

“One species I think is critical to rocky shore balance is ___ because ___.”

Collect these on the way out as a formative assessment check-in.

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Differentiation Notes

• Lower literacy students can choose diagrams and discuss orally with support.
• Advanced students can link with abiotic changes (e.g., temperature or salinity) as a preview to next unit.
• Ākonga Māori and Pacific learners are encouraged to bring in mātauranga Māori or traditional knowledge of coastal ecosystems.

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Assessment Notes

These activities lay the groundwork for Achievement Standard AS91158 (Investigate a pattern in an ecological community), particularly in exploring biotic factors affecting populations.

Evidence collected via:

• Group discussions
• Sticky note predictions
• Paragraph writing
• Exit cards

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Possible Follow-On Lessons

• Field trip planning to local rocky shore or virtual exploration of NZ rocky coastlines
• Introduce abiotic factors next (e.g., exposure, salinity, wave action)
• Build toward a real-data investigation around population patterns (crab counts, mollusc competition)

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🇳🇿 Made for New Zealand classrooms – grounded in local ecosystems, cultural perspectives & collaborative learning.