Biology Year 12 - Module 5 - Lesson 13

Sources of Genetic Variation - Meiosis, Crossing Over, Fertilisation, Mutation

Use this worksheet after reading the lesson to practise the key ideas and prove you can meet the success criteria.

Name

Date

Class

1. Key Ideas

Variation in offspring is not caused by a single process. Some variation comes from reshuffling existing alleles during meiosis and fertilisation, while mutation creates entirely new alleles.

Major sources of genotype variation in sexually reproducing organisms.
Why crossing over and independent assortment reshuffle existing alleles.

2. Success Criteria

By the end, you should be able to:

Major sources of genotype variation in sexually reproducing organisms.
That mutation is the source of new alleles.
Why crossing over and independent assortment reshuffle existing alleles.

3. Key Terms

Genetic variationDifferences in genetic makeup within or between individuals of a population.

Crossing overExchange of corresponding chromosome segments between homologous chromosomes during meiosis.

Independent assortmentRandom orientation and separation of homologous chromosomes in meiosis.

Random fertilisationThe chance fusion of one gamete with another, creating many possible genotype combinations.

MutationA change in DNA sequence that can create a new allele.

AlleleAn alternative version of a gene.

4. Activity: Build the Lesson Map

Use the lesson to complete the table. Keep answers brief but specific.

Prompt	Your answer
Main concept
Important example
Common mistake to avoid
How this links to the next lesson

5. Short Answer Questions

1. Explain this lesson goal in your own words: "Major sources of genotype variation in sexually reproducing organisms.". Use one specific example from the lesson.

Band 32 marks

2. Apply this idea to a new example: "That mutation is the source of new alleles.". Show your reasoning clearly.

Band 43 marks

3. Analyse why this idea matters for understanding Sources of Genetic Variation - Meiosis, Crossing Over, Fertilisation, Mutation: "Why crossing over and independent assortment reshuffle existing alleles.".

Band 54 marks

6. Extend: Apply the Idea

Band 5/65 marks

A student gives a memorised answer about Sources of Genetic Variation - Meiosis, Crossing Over, Fertilisation, Mutation but does not use evidence or reasoning.

Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.

7. Multiple Choice

1. What is the best first step when answering a question about Sources of Genetic Variation - Meiosis, Crossing Over, Fertilisation, Mutation?

A. Identify the key concept being tested

B. Write every fact from memory

C. Ignore the command word

D. Skip examples and evidence

2. Which answer would show stronger understanding of Sources of Genetic Variation - Meiosis, Crossing Over, Fertilisation, Mutation?

A. An answer with accurate terms and reasoning

B. A copied definition only

C. A single-word response

D. An answer with no example

3. What should you do if a question asks you to explain?

A. Link the idea to a reason or cause

B. List unrelated facts

C. Only draw a diagram

D. Write the shortest possible answer

8. Success Criteria Proof

Finish with evidence that you can do each success criterion.

Success criterion 1

Prove that you can: Major sources of genotype variation in sexually reproducing organisms.