Year 9 Genetics and Evolution Worksheet - Beginner

Year 9 Genetics and Evolution worksheet for Year 9 (Key Stage 3 / Year 7-9 (Ages 11-14)). Beginner level science practice, aligned to the UK National Curriculum. Print-ready with answer key included.

Science•Key Stage 3 / Year 7-9 (Ages 11-14)•Genetics and Evolutionbeginner

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Genes, Variation and Evolution

Year 9 Science • Ages 13–14 • Beginner

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Instructions: Work through the activities in order. Use the information in each question, and explain scientific ideas in your own words where asked. Check that you have answered every part before finishing.

DNA, genes and chromosomes

Use the word bank to complete each sentence. Each word is used once. Remember: chromosomes are made of DNA, and genes are sections of DNA.

Word bank: DNA, genes, chromosomes, inherited

1. Long molecules of __________ are packaged into structures called chromosomes.

2. Short sections of DNA that influence characteristics are called __________.

3. Different forms of the same gene are called alleles; they can be passed from parents to offspring, so they are __________.

4. A gene is a section of __________ that carries instructions affecting a characteristic.

Inheritance and variation

Read the examples and identify whether each feature is mainly inherited, mainly environmental, or influenced by both. Then give one reason why variation within a species can be useful.

1. A person’s natural eye colour is mainly inherited, environmental, or both?

2. A person’s accent is mainly inherited, environmental, or both?

3. A person’s adult height is mainly inherited, environmental, or both?

4. Give one reason why variation in a population can help some individuals survive a change in the environment.

Natural selection: a moth population

Use the data and the natural-selection steps to answer the questions. A bird predator can more easily see pale moths on dark tree bark. Think about which moths survive and reproduce, and how this can change the population over generations.

Generation	Pale moths	Dark moths
1	60	40
2	35	65
3	15	85

1. How many dark moths were in Generation 1?

2. Which colour of moth increased in number from Generation 1 to Generation 3?

3. Explain why dark moths were more likely to survive on dark bark.

4. Describe how the proportion of dark moths could increase over many generations.

Darwin and Mendel

Choose the correct answer for each question. Darwin studied how species change and adapt over time; Mendel investigated how characteristics are inherited using pea plants.

1. Which scientist is best known for explaining evolution by natural selection?

2. Which scientist studied inheritance patterns in pea plants?

3. What is natural selection?

4. What did Mendel’s pea-plant experiments help scientists understand?

Extinction and gene banks

Answer using your knowledge of biodiversity and conservation. A gene bank stores genetic material, such as seeds, to help preserve variation; it cannot by itself restore a species’ habitat or guarantee that an extinct species will return.

1. What does extinction mean?

2. Give one reason why a species might become extinct.

3. What is one way a seed gene bank can help conserve plant biodiversity?

4. Give one limitation of relying on a gene bank to protect a species.

Answer Key

Activity 1: DNA; genes; inherited; DNA

Activity 2: Mainly inherited; mainly environmental; both; Accept a reason such as variation means some individuals may have characteristics that help them survive and reproduce when conditions change.

Activity 3: 40; dark moths; Dark moths are better camouflaged against dark bark, so predators are less likely to see and eat them; Dark moths are more likely to survive and reproduce, passing on alleles associated with dark colour. Over generations, those alleles become more common and the proportion of dark moths increases.

Activity 4: Charles Darwin; Gregor Mendel; Individuals with useful inherited variations are more likely to reproduce; How characteristics can be passed between generations

Activity 5: When no living individuals of a species remain; Accept habitat loss, environmental change, disease, hunting, or another valid cause; It stores seeds and their genetic variation for future conservation or research; It cannot by itself restore habitat or guarantee the return of an extinct species.