AQA GCSE Biology (8461), Higher tier · Inheritance, variation and evolution › Understanding of genetics and evolution
Practise Theory of 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 characteristics most suited to the environment are more likely to ..................................... .
survive and breed (reproduce)
The statements describe how natural selection could change a population of rabbits living in a cold area. A Rabbits with thicker fur are more likely to survive the cold winters and breed. B Over many generations, most rabbits in the population have thick fur. C The rabbits in the population show variation in the thickness of their fur. D The alleles for thick fur are passed on to the offspring. Write the letters A, B, C and D in the correct order.
C, A, D, B
Darwin published his theory in 1859. Give the title of the book in which he published it.
On the Origin of Species
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy6 marks
Charles Darwin proposed the theory of evolution by natural selection.
(a) In which year did Darwin publish On the Origin of Species? Tick (✓) one box.[1]
1759
1859
1909
1959
(b) Which two of the following did Darwin use to develop his theory? Tick (✓) two boxes.[2]
Comparing the DNA of different species
Knowledge of geology and fossils
Observations made on a round-the-world expedition
Studying the structure of chromosomes
Testing bacteria for resistance to antibiotics
(c) Darwin's theory was only gradually accepted. Give two reasons why.[2]
(d) Complete the sentence. Individuals with characteristics most suited to the environment are more likely to ..................................... .[1]
Show the answer and mark scheme
(a)Answer: 1859
(b)Answer: Knowledge of geology and fossils; Observations made on a round-the-world expedition
(c)
the theory challenged the idea that God made all the animals and plants that live on Earth
there was insufficient evidence at the time to convince many scientists
the mechanism of inheritance and variation was not known (until about 50 years later) / genes had not been discovered
(d)Answer: survive and breed (reproduce)
survive and breed / survive and reproduce
Question 2Medium7 marks
Some species of wading bird have very long legs. This lets them feed in deep water. Here are two statements that try to explain how the long legs evolved. Statement A: The ancestors of these birds stretched their legs to keep their feathers dry when wading into deep water. The legs of each bird became slightly longer during its life, and its offspring were born with these longer legs. Statement B: The ancestors of these birds had legs of different lengths. Birds with longer legs could reach more food, so they were more likely to survive and breed. Their offspring inherited long legs.
(a) Statement A is based on the theory of one scientist. Who was this scientist? Tick (✓) one box.[1]
Charles Darwin
Jean-Baptiste Lamarck
Gregor Mendel
Alfred Russel Wallace
(b) Scientists now know that the type of inheritance described in statement A does not happen in the vast majority of cases. Explain why.[2]
(c) Statement B does not explain how some birds came to have longer legs than others. Use your knowledge of genes to explain how a bird with longer legs could first have appeared in the population.[2]
(d) When Darwin published his theory, genes had not been discovered. Explain how the later discovery of genes helped scientists to accept Darwin's theory.[2]
Show the answer and mark scheme
(a)Answer: Jean-Baptiste Lamarck
(b)
changes that happen to an organism during its lifetime do not (usually) change its genes / DNA
(so the change) is not passed on in the gametes / sex cells / only genes (alleles) are inherited
(c)
a mutation / change in the DNA (of a gene)
produced a new allele / new variant (that caused longer legs)
(d)
genes explained how characteristics are passed on / inherited by offspring
genes / mutations explained how variation arises (which Darwin could not explain)
Question 3Hard7 marks
Darwin's theory of evolution by natural selection was based on observations made on a round-the-world expedition. It was backed by years of experimentation and discussion, and linked to developing knowledge of geology and fossils.
(a) At the time, many people believed that the Earth was only a few thousand years old. Explain why Darwin's theory needed the Earth to be much older than this.[2]
(b) Fossils in older, deeper rock layers are generally less similar to species alive today than fossils in younger rock layers. Explain how this supported Darwin's theory.[2]
(c) When Darwin published his theory, the mechanism of inheritance was not known. It was not understood until about 50 years later. Explain why this made it difficult for many scientists to accept Darwin's theory.[2]
(d) Darwin spent about 20 years collecting evidence and carrying out experiments before he published his theory. Suggest why.[1]
Show the answer and mark scheme
(a)
evolution by natural selection is (very) slow / gradual
(because) it needs a very large number of generations for changes to build up / for new species to form
(b)
it shows that species have changed (gradually) over a long time
(it suggests that) present-day species evolved from earlier / simpler forms of life
(c)
Darwin could not explain how characteristics are passed from parents to offspring / how variation arises
(so) there was not enough evidence to convince scientists / the theory seemed incomplete
(d)
to collect enough evidence to support the theory / to convince other scientists
(because) he knew the theory would be controversial / would challenge the idea that God made all living things