Inheritance, variation and evolution
Learn Inheritance, variation and evolution for Year 9 pupils (ages 13–14). Free practice questions, lessons and worked examples — aligned to the UK National Curriculum.
What you'll learn
- 1
Genes are sections of DNA that carry instructions. You inherit one copy of each gene from each parent.
- 2
If an allele is dominant, one copy is enough to show. A recessive feature needs two copies — which is why it can skip a generation and reappear.
- 3
How many copies of a recessive allele are needed for the feature to show?
- 4
Common error: "giraffes stretched their necks and passed that on." They did not. Variation already existed; longer-necked giraffes survived better and had more offspring.
- 5
What does natural selection act on?
- 6
Apply it: two brown-furred rabbits, each carrying one white allele (Bb), have offspring. The cross gives BB, Bb, Bb, bb — a 1 in 4 chance of a white rabbit.
- 7
Two Bb parents. What is the chance of a bb offspring?
Practise Inheritance, variation and evolution with Whizlo
Free AI-tutored lessons, unlimited practice questions, and progress tracking for ages 13–14. Aligned to the UK National Curriculum.