| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: explain that stomata respond to changes in environmental conditions by opening and closing and that regulation of stomatal aperture balances the need for carbon dioxide uptake by diffusion with the need to minimise water loss by transpiration |
Learning Objective/s:
- Describe the structure of stomata and the role of guard cells.
- Explain how light, CO₂, humidity, temperature and ABA influence stomatal aperture.
- Illustrate the ion‑transport mechanisms that drive opening and closing.
- Analyse how stomatal regulation balances photosynthetic CO₂ uptake with water loss.
- Apply knowledge to predict plant responses to drought conditions.
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Materials Needed:
- Projector and PowerPoint slides
- Printed worksheet with diagram of a leaf
- Fresh leaf samples (e.g., spinach) and transparent coverslips
- Microscope (optional for guard‑cell observation)
- Interactive stomatal simulation on tablets/computers
- Exit‑ticket cards
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Introduction:
Begin with a quick poll: “If a plant runs out of water, what happens to its leaves?” Connect this to prior knowledge of photosynthesis and gas exchange. State that today’s success criteria are to identify the signals that control stomata and to explain how opening and closing balance CO₂ intake with water loss.
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Lesson Structure:
- Do‑now (5'): Students answer a short question on gas exchange and submit responses via clickers.
- Mini‑lecture (10'): Overview of stomatal anatomy and the six key environmental signals.
- Interactive simulation (15'): Learners manipulate light, CO₂, humidity and ABA to see real‑time changes in aperture.
- Practical demonstration (10'): Leaf‑disc assay showing stomatal opening under light vs. closure under ABA spray.
- Guided data analysis (10'): Groups interpret results and relate them to the trade‑off between CO₂ uptake and water loss.
- Check for understanding (5'): Exit‑ticket – “Name one signal that causes closure and explain why.”
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Conclusion:
Recap the main signals and mechanisms that regulate stomatal aperture, emphasizing the balance between photosynthesis and transpiration. Collect exit‑tickets to gauge understanding, and assign a short homework task: research one crop where stomatal manipulation improves drought tolerance and prepare a one‑page summary.
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