AQA GCSE Biology (8461), Higher tier · Inheritance, variation and evolution › Understanding of genetics and evolution
Practise Speciation. 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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In 1858 Wallace and Darwin published joint writings. What did this prompt Darwin to do the following year?
Publish On the Origin of Species (1859)
Put the statements in the correct order. Statement B has been done for you. B → ....... → ....... → ....... → .......
B, D, C, E, A
Sample questions
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy4 marks
Alfred Russel Wallace was a scientist who worked at the same time as Charles Darwin.
(a) Wallace independently proposed a scientific theory. Which theory? Tick (✓) one box.[1]
The gene theory
The theory of evolution by natural selection
The theory that characteristics gained during life are inherited
The three-domain system of classification
(b) Wallace is best known for his theory of speciation and for his work on one other topic. What was the other topic? Tick (✓) one box.[1]
Antibiotic resistance in bacteria
The structure of DNA
Naming organisms using two names
Warning colouration in animals
(c) In 1858 Wallace and Darwin published joint writings. What did this prompt Darwin to do the following year?[1]
(d) Speciation is the formation of new species. What is a species?[1]
Show the answer and mark scheme
(a)Answer: The theory of evolution by natural selection
(b)Answer: Warning colouration in animals
(c)Answer: Publish On the Origin of Species (1859)
publish (the book) On the Origin of Species / publish his theory
(d)Answer: A group of organisms that can breed together to produce fertile offspring
a group of organisms that can (inter)breed to produce fertile offspring
Question 2Medium7 marks
A species of small mouse lived across a large area of grassland. A wide river changed its course and split the population into two. The mice cannot cross the river. Over thousands of years the conditions on the two sides of the river became different. On one side the grass became taller and denser. On the other side the land became drier, with sandy soil.
(a) The two populations of mice may eventually become two different species. Describe how.[4]
(b) Scientists want to find out whether the two populations have become different species. Describe how they could do this.[2]
(c) Suggest one characteristic that might be selected for in the population on the dry, sandy side of the river.[1]
Show the answer and mark scheme
(a)
the populations are isolated (by the river) / cannot interbreed
there is (genetic) variation in each population / mutations occur in each population
the conditions / environments on the two sides are different
natural selection: in each population the individuals with the most suitable characteristics survive and breed
different alleles are passed on / become more common in each population
(eventually) the populations become so different that they can no longer interbreed to produce fertile offspring
(b)
breed a mouse from one population with a mouse from the other population
find out whether the offspring are fertile / can breed (if they are not, the populations are different species)
(c)
sandy / pale fur (for camouflage)
ability to survive with less water / produce concentrated urine
strong claws / legs for digging burrows in sandy soil
Question 3Hard8 marks
About 10 000 years ago a large lake contained one species of fish. The water level then fell, and the lake split into two separate lakes, X and Y, which have never been joined since.
Lake X is deep and cold. It contains a species of large predatory fish.
Lake Y is shallow and warm. It has no predatory fish, but many insects land on the water surface.
Today, the fish in lake X and the fish in lake Y are different species.
(a) Explain how the fish in the two lakes could have evolved into two different species.[6]
(b) Fish from lake X and lake Y can be made to breed in an aquarium, but all of their offspring are infertile. Explain how this shows that the fish in the two lakes are different species.[2]
Show the answer and mark scheme
(a)
the two populations were isolated / could not interbreed after the lake split
there was genetic variation in each population, and mutations produced new alleles
conditions in the two lakes were different, e.g. temperature, depth, predators, food
in lake X, fish that could escape predators (e.g. faster swimmers or better camouflaged) or survive the cold were more likely to survive and breed
in lake Y, fish that were better at catching insects at the surface were more likely to survive and breed
the survivors passed on their alleles, so different alleles became more common in each lake (natural selection)
this continued over many generations
eventually the populations became so different that they could no longer interbreed to produce fertile offspring
Marked with levels of response: the full level descriptors are in the app.
(b)
a species is a group of organisms that can interbreed to produce fertile offspring
the offspring are infertile, so fish from X and Y cannot produce fertile offspring together