Exam questions · Biology · Evolution and Natural Selection
Darwin and Wallace
- 6 exam questions
- 22 marks
- 9 quick checks
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1 State [2 marks]
State the names of the two scientists who put forward the theory of evolution by natural selection.
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Model answer
Charles Darwin and Alfred Russel Wallace.
Mark scheme
- Darwin — 1 mark
- Wallace — 1 mark
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2 Describe [3 marks]
Describe how Darwin collected evidence for his theory.
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Darwin travelled round the world on HMS Beagle, collecting plants, animals and fossils. He studied the animals of the Galápagos Islands, such as finches and tortoises, and noticed differences between the islands. He also studied selective breeding by pigeon breeders.
Mark scheme
- Voyage on the Beagle — 1 mark
- Galápagos species — 1 mark
- Selective breeding — 1 mark
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3 Explain [3 marks]
Explain why Darwin delayed the publication of his theory.
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He wanted to collect more evidence and to check his ideas thoroughly. He also knew that the theory would upset many people because it contradicted religious beliefs about creation.
Mark scheme
- Wanted more evidence — 1 mark
- Aware it would upset people — 1 mark
- Contradicted beliefs about creation — 1 mark
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4 Explain [4 marks]
Explain why the theory of evolution by natural selection was not accepted by everyone when it was first published.
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Many people believed that species had been created separately, and the theory conflicted with religious teaching. The idea that humans shared an ancestor with apes was offensive to some people. Evolution is very slow, so the evidence could not be seen directly, and there was no mechanism to explain how characteristics are inherited.
Mark scheme
- Religious beliefs — 1 mark
- Humans and apes — 1 mark
- Too slow to observe — 1 mark
- No mechanism for inheritance — 1 mark
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5 Explain [4 marks]
Explain how the discovery of genes and DNA made the theory of evolution more convincing.
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Darwin could not explain how features are passed from parents to offspring. Genetics showed that characteristics are controlled by genes, which are passed on in gametes, and that DNA can mutate to produce new variation. This gave the mechanism for both inheritance and variation, which supports natural selection.
Mark scheme
- Darwin had no mechanism of inheritance — 1 mark
- Genes pass on characteristics — 1 mark
- Mutations give new variation — 1 mark
- This supports natural selection — 1 mark
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6 Evaluate [6 marks]
Evaluate the importance of the work of Darwin and Wallace to modern biology.
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Model answer
Darwin and Wallace independently developed the idea that species change over time by natural selection. Darwin supported it with a large amount of evidence from the Beagle voyage, the Galápagos and selective breeding, and Wallace added evidence from his collecting. The theory explained the variety of life and the fact that all organisms are related by common ancestors, and it is now the basis of biology. When genetics and DNA were discovered, they supplied the missing mechanism of inheritance and variation. The theory also helps to explain modern problems such as antibiotic resistance. It is therefore the unifying idea of the subject.
Mark scheme
- They developed natural selection — 1 mark
- Evidence from Darwin — 1 mark
- Wallace's independent work — 1 mark
- Explains common ancestry — 1 mark
- Genetics supplied the mechanism — 1 mark
- A modern application, such as antibiotic resistance — 1 mark
Quick check
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1
Which scientist sailed on HMS Beagle?
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B: Darwin
Charles Darwin sailed on HMS Beagle from 1831 to 1836.
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2
In which year was On the Origin of Species published?
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C: 1859
Darwin published his book in 1859.
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3
Which scientist independently came up with the idea of natural selection?
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A: Alfred Russel Wallace
Alfred Russel Wallace reached the same conclusion on his own, and sent it to Darwin in 1858.
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4
On which group of islands did Darwin study finches?
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D: The Galápagos Islands
Darwin studied finches and other animals on the Galápagos Islands.
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5
Which was a reason why many people rejected Darwin's theory?
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B: It conflicted with the belief that species were created separately
It went against the religious belief that each species had been created separately.
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6
What did Darwin not know about?
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C: Genes and how inheritance works
Darwin did not know how characteristics are inherited, because genes had not yet been discovered.
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7
Which discovery later provided the mechanism of inheritance?
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D: Genetics
Genetics, including Mendel's work and the discovery of DNA, explained inheritance.
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8
Why did Darwin study pigeon breeders?
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A: Selective breeding produces new varieties, like natural selection
Breeders choose parents to produce new varieties, which gave Darwin an idea of how nature might select.
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9
Why was it important that Wallace reached the same idea independently?
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B: It supported the idea and pushed Darwin to publish
Two scientists arriving at the same conclusion from different evidence gave the idea more support, and pushed Darwin to publish.