AQA GCSE Biology (8461), Higher tier · Inheritance, variation and evolution › Variation and evolution
Practise Evolution. 14 exam-style questions plus unlimited generated ones 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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Complete the sentence. Individuals with the characteristics best suited to their environment are more likely to .......... and ..........
survive and reproduce (breed)
A population of rabbits lives in a cold area. The sentences below describe how natural selection could make thick fur more common in the population, but they are in the wrong order. A Rabbits with thicker fur are more likely to survive a cold winter. B There is variation in fur thickness in the population. C The allele for thick fur becomes more common over many generations. D The surviving rabbits breed and pass on the allele for thick fur. Write the letters in the correct order.
B, A, D, C
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy6 marks
The theory of evolution by natural selection explains how living things have changed over time.
(a) What is evolution? Tick (✓) one box.[1]
A change in the inherited characteristics of a population over time through natural selection
The changes that happen to an individual during its lifetime
The process by which a species becomes extinct
The production of offspring from one parent
(b) All species of living things have evolved from simple life forms. When did these simple life forms first develop? Tick (✓) one box.[1]
More than three thousand years ago
More than three million years ago
More than three billion years ago
More than three trillion years ago
(c) Complete the sentence. Individuals with the characteristics best suited to their environment are more likely to .......... and ..........[2]
(d) Two populations of one species can become so different in phenotype that they form two new species. How can you tell when this has happened?[2]
Show the answer and mark scheme
(a)Answer: A change in the inherited characteristics of a population over time through natural selection
(b)Answer: More than three billion years ago
(c)Answer: survive and reproduce (breed)
survive
reproduce / breed
(d)Answer: They can no longer interbreed to produce fertile offspring
they can no longer interbreed
to produce fertile offspring
Question 2Medium6 marks
A population of frogs was split into two when a river changed its course. After many thousands of years, scientists put frogs from the two populations together.
(a) Describe how the scientists could find out whether the two populations had become different species.[2]
(b) Horses and donkeys can mate and produce offspring called mules. Mules are infertile. Are horses and donkeys the same species? Explain your answer.[2]
(c) Suggest how natural selection could have made the two populations of frogs different from each other.[2]
Show the answer and mark scheme
(a)Answer: See whether frogs from the two populations can interbreed, and whether any offspring are fertile
see whether they can interbreed / mate and produce offspring
see whether the offspring are fertile / can themselves reproduce
(b)Answer: No: although they can interbreed, their offspring are not fertile
no / different species
because their offspring (mules) are not fertile
(c)Answer: Conditions on each side of the river were different, so different variants were best suited and survived to reproduce in each population
the environment / conditions were different on each side of the river
so different variants survived and reproduced in each population (and the populations could not interbreed)
Question 3Hard8 marks
A species of moth feeds on nectar from flowers using a long tongue. On one island the only flowers available have very long, narrow tubes, with the nectar at the bottom. Over 40 years, the mean tongue length of the moths on the island increased from 18 mm to 25 mm.
(a) Calculate the percentage increase in mean tongue length. Give your answer to 3 significant figures.[2]
(b) Explain how natural selection could have caused the increase in mean tongue length.[6]
Show the answer and mark scheme
(a)Answer: 38.9%
(25 − 18) ÷ 18 × 100
38.9 (%)
(b)Answer: Level 3 answers explain variation, selection pressure, differential survival and reproduction, inheritance of alleles and change over many generations
there was variation in tongue length in the population
caused by differences in genes / alleles, which arise from mutations
moths with longer tongues could reach the nectar in the long flowers
so they got more food / energy
and were more likely to survive and reproduce
they passed on the alleles for long tongues to their offspring
moths with short tongues were less likely to survive and reproduce
over many generations the proportion of moths with long tongues increased, so the mean tongue length increased
Marked with levels of response: the full level descriptors are in the app.