1. What makes us different?
Variation and Meiosis
What makes us different?

2. Lesson Objectives
Understand genetic and environmental variation, using examples
Understand the processes of Crossing Over, Independent assortments & Fertilisation
Know how these processes contribute to variation in offspring.

3. Starter Activity
You each have a post it note with a stage of Meiosis written on it.
Draw that stage on the post it.
Stick it to the window.

4. Variation
Brainstorm all the characteristics / traits that make us different.
These could be genetic or environmental features.

5. Variation What is meant by Genetic Difference (Variation)?

6. Activity.
Complete the Variation worksheet activity in pairs or small groups.

7. Crossing Over
Write down a definition of Crossing Over from the work we did yesterday.
When (which stage) during Meiosis does it happen?
Why is it important?

8. Independent Assortment
Sometimes called independent segregation or random assortment.
Happens in Metaphase 1 and Metaphase 2

9. Metaphase 1
When chromosomes line up along the equator with their homologous pairs, they do so randomly.
i.e. There is no specific order

10. Anaphase 1
So, when they separate from their homologous pair in anaphase, this is also random.

11. Metaphase 2/ Anaphase 2/Telophase 2
Again, another random order
So, when the 4 daughter haploid cells are formed there is a random combination (independent assortment) of chromosomes.
This means that there can be a lot of variation in offspring.

12. Fertilisation
How does the process of fertilisation contribute to genetic variation?

13. Genetic Variation