Topic: Tropic Responses
Lesson 1: Introduction to Tropic Responses
| Section | Details |
|---|---|
| Objective | – Understand and describe gravitropism and phototropism as responses to gravity and light. |
| Activities | Starter (5 mins): Show images or videos of plants bending toward light and roots growing downward in soil. Main (25 mins): 1. Define gravitropism and phototropism. 2. Discuss the significance of these responses in plants’ survival. Plenary (10 mins): Students summarize the differences between gravitropism and phototropism with examples. |
| Resources | Time-lapse videos of plant growth, diagrams showing shoot and root growth. |
| Time | 40 minutes |
| Homework | Research and write a paragraph on the importance of phototropism for photosynthesis. |
| Assessment | Class participation during the plenary discussion. |
| Past Paper Practice | IGCSE Biology 0610/21/M/J/20 Q3(a). |
Lesson 2: Investigating Gravitropism and Phototropism
| Section | Details |
|---|---|
| Objective | – Investigate and describe the effects of light and gravity on plant shoots and roots. |
| Activities | Starter (5 mins): Ask students to predict how roots and shoots will grow in different orientations or under different light conditions. Main (25 mins): 1. Conduct experiments using potted plants placed horizontally to observe gravitropism. 2. Use a setup with directional light to observe phototropism. Plenary (10 mins): Students discuss their observations and relate them to plant survival. |
| Resources | Potted plants, cardboard boxes, light sources, moist soil. |
| Time | 40 minutes |
| Homework | Write an observation report from the experiments conducted in class. |
| Assessment | Students explain their observations and relate them to plant responses during the plenary. |
| Past Paper Practice | IGCSE Biology 0610/42/O/N/19 Q2(b). |
Lesson 3: Role of Auxin in Tropic Responses
| Section | Details |
|---|---|
| Objective | – Explain the role of auxin in controlling shoot and root growth in response to light and gravity. |
| Activities | Starter (5 mins): Show a diagram of auxin distribution in a plant exposed to light. Main (25 mins): 1. Explain how auxin is produced in the shoot tip and diffuses unevenly in response to light or gravity. 2. Discuss how auxin causes cell elongation and its role in phototropism and gravitropism. Plenary (10 mins): Students summarize the role of auxin in plant growth. |
| Resources | Diagrams showing auxin distribution and its effects, whiteboard for notes. |
| Time | 40 minutes |
| Homework | Draw a labeled diagram explaining how auxin affects phototropism and gravitropism in shoots and roots. |
| Assessment | Students explain the role of auxin using the diagrams they create. |
| Past Paper Practice | IGCSE Biology 0610/32/M/J/18 Q3(b). |
Lesson 4: Chemical Control of Plant Growth
| Section | Details |
|---|---|
| Objective | – Understand phototropism and gravitropism as examples of chemical control in plants. |
| Activities | Starter (5 mins): Ask students why plant shoots grow toward light and roots grow downward. Main (25 mins): 1. Discuss how auxin distribution results in bending toward light or gravity. 2. Explain the effects of auxin on cells in different regions of the plant. Plenary (10 mins): Students write a short explanation of how auxin controls growth in plant shoots. |
| Resources | Auxin experiment results, diagrams of shoots and roots exposed to light and gravity. |
| Time | 40 minutes |
| Homework | Write an explanation of how auxin distribution differs in shoots and roots. |
| Assessment | Class participation during discussions and written explanations during the plenary. |
| Past Paper Practice | IGCSE Biology 0610/21/M/J/19 Q5(a). |
Key Notes for Teachers:
- Use real-life experiments to show how light and gravity affect plant growth.
- Emphasize the role of auxin in both phototropism and gravitropism.
- Relate plant responses to their survival in different environments.
Key Notes for Students:
- Tropisms are plant responses to stimuli like light and gravity.
- Auxin controls plant growth by being unevenly distributed in response to light and gravity.
- Phototropism helps plants maximize photosynthesis, while gravitropism anchors roots for water and nutrient uptake.
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