| Lesson Plan |
| Grade: |
Date: 25/02/2026 |
| Subject: Biology |
| Lesson Topic: explain that crossing over and random orientation (independent assortment) of pairs of homologous chromosomes and sister chromatids during meiosis produces genetically different gametes |
Learning Objective/s:
- Describe the processes of crossing over and independent assortment during meiosis.
- Explain how crossing over creates new allele combinations on chromosomes.
- Explain how independent assortment leads to different chromosome combinations in gametes.
- Analyze how the combined effects generate genetically distinct gametes.
- Apply knowledge to predict variation outcomes in hypothetical meiosis scenarios.
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Materials Needed:
- Projector or interactive whiteboard
- PowerPoint slides or digital presentation on meiosis
- Printed handouts with diagrams of tetrads and chromosome alignment
- Colored paper or cut‑out chromosome models
- Worksheets for practice problems on gamete combinations
- Exit‑ticket cards
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Introduction:
Begin with a short video clip showing genetic variation in offspring, then ask students to recall how meiosis differs from mitosis. Connect prior knowledge of chromosome pairs to today’s focus on how crossing over and independent assortment create diversity. Outline the success criteria: students will be able to describe both mechanisms and predict their impact on gamete genetics.
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Lesson Structure:
- Do‑now (5'): Students answer a brief question on the differences between meiosis I and II from the previous lesson.
- Mini‑lecture (10'): Overview of crossing over with a diagram of a tetrad; highlight key terminology.
- Interactive model (10'): In pairs, students use colored‑paper chromosomes to simulate crossing over and record new allele combinations.
- Guided practice (8'): Explain independent assortment; show an animation of random chromosome alignment and discuss the 2ⁿ possibilities.
- Group activity (12'): Using dice or cards, groups model random orientation of chromosome pairs and calculate possible gamete combinations for a given n.
- Check for understanding (5'): Quick Kahoot quiz with three questions linking both mechanisms to genetic variation.
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Conclusion:
Summarize that crossing over reshuffles alleles on individual chromosomes while independent assortment shuffles whole chromosome sets, together producing millions of unique gametes. Students write one takeaway on an exit ticket and submit it. For homework, assign a worksheet where they calculate the number of possible gametes for organisms with different chromosome numbers.
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