AQA GCSE Biology (8461), Higher tier · Inheritance, variation and evolution › Variation and evolution
Practise Variation. 13 exam-style questions on this subtopic, at up to four difficulty levels, with full mark schemes and a progress tracker. Free, no account needed.
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Body mass is affected by both genes and the environment. Give one environmental factor that affects body mass.
Diet / amount of exercise
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy5 marks
Differences in the characteristics of individuals in a population are called variation.
(a) Which characteristic is caused only by genetic factors? Tick (✓) one box.[1]
Blood group
Body mass
Language spoken
A scar on the knee
(b) Which characteristic is caused only by the environment? Tick (✓) one box.[1]
Blood group
Eye colour
Height
A tattoo
(c) Body mass is affected by both genes and the environment. Give one environmental factor that affects body mass.[1]
(d) All genetic variants arise in the same way. What causes genetic variants?[1]
(e) Which statement about genetic variants is correct? Tick (✓) one box.[1]
Most genetic variants determine the phenotype
Most genetic variants have no effect on the phenotype
Most genetic variants are harmful
Most genetic variants are useful
Show the answer and mark scheme
(a)Answer: Blood group
(b)Answer: A tattoo
(c)Answer: Diet / amount of exercise
diet / amount of food eaten / exercise
(d)Answer: Mutations
mutation(s)
(e)Answer: Most genetic variants have no effect on the phenotype
Question 2Medium5 marks
Variation between individuals can be caused by genes, by the environment, or by a combination of both.
(a) Classify each characteristic as caused mainly by genes, mainly by the environment, or by a combination of both. Natural hair colour .......... The language a person speaks .......... Height ..........[3]
(b) Two plants were grown from seeds produced by the same two parent plants. They were grown in the same greenhouse, but one plant grew much taller than the other. Suggest two reasons for this difference.[2]
Show the answer and mark scheme
(a)Answer: Genes; environment; a combination of both
natural hair colour: genes
the language a person speaks: environment
height: a combination of both
(b)Answer: The seeds were produced by sexual reproduction, so the plants inherited different alleles; and one plant may have had more light, water or mineral ions than the other
genetic: the seeds were produced by sexual reproduction, so the plants inherited different alleles / different combinations of genes for height
environmental: one plant may have received more light / water / mineral ions (e.g. because of its position in the greenhouse)
Question 3Hard4 marks
Variation between individuals is essential for both natural selection and selective breeding.
(a) Explain why a population with very little genetic variation would respond poorly to natural selection if the environment changed suddenly.[2]
(b) Explain why a population with very little genetic variation would also be of limited use to a breeder trying to improve a characteristic by selective breeding.[2]
Show the answer and mark scheme
(a)Answer: Natural selection relies on some individuals being better suited to the changed conditions than others; with little variation there is little difference between individuals, so few may be well suited to the new conditions
natural selection relies on some individuals being better suited to survive changed conditions than others
with little variation there is little difference between individuals, so few (or none) may be well suited to the new conditions, risking a large population decline
(b)Answer: A breeder selects individuals with the most desirable version of a characteristic to breed from; with little variation there is little difference to select between, so progress would be very slow
a breeder selects individuals with the most desirable version of a characteristic to breed from
with little variation there is little difference to select between, so progress towards an improved characteristic would be very slow or impossible