Lesson Plan

• Describe the diploid and haploid chromosome states in organisms.
• Explain why a reduction division is required for gamete formation.
• Compare meiosis and mitosis regarding chromosome number and genetic variation.
• Identify the stage(s) of meiosis where chromosome number is reduced.
• Evaluate the consequences of omitting reduction division.

• Projector or interactive whiteboard
• Slide deck illustrating meiosis stages
• Printed worksheet with comparison table and diagram prompts
• Chromosome model kit (or 3‑D meiosis set)
• Markers and chart paper for group mind‑map
• Exit‑ticket slips

Begin with a quick poll: “If a sperm and egg each contributed a full set of chromosomes, what would happen to the offspring?” Connect this to students’ prior knowledge of diploid vs. haploid cells. State that by the end of the lesson they will be able to explain why meiosis must halve chromosome number and how this supports stable inheritance and variation.

1. Do‑now (5') – Short quiz on diploid/haploid concepts; collect responses.
2. Mini‑lecture (10') – Review meiosis phases, emphasizing the reductional division in Meiosis I with slide visuals.
3. Venn diagram activity (8') – In pairs, compare mitosis and meiosis using a printed table; share key differences.
4. Model demonstration (12') – Small groups use chromosome kits to model homologous pairing, crossing‑over, and segregation in Meiosis I.
5. Think‑pair‑share (5') – Discuss what would occur if reduction division were skipped; record ideas on chart paper.
6. Formative check (5') – Exit ticket: “In one sentence, why is reduction division essential for gamete production?”

Summarise that meiosis halves chromosome number, prevents exponential chromosome buildup, and creates genetic diversity. Collect exit tickets to gauge understanding, and assign a brief homework: create a labelled diagram of Meiosis I highlighting where reduction occurs.