AQA GCSE Biology (8461), Higher tier · Ecology › Organisation of an ecosystem
Practise Impact of environmental change. 11 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.
Written for this site in the style of AQA exam questions. They are not taken from real past papers.
Question 1Easy5 marks
Environmental changes affect the distribution of species in an ecosystem.
(a) Which two of the following are environmental changes that can affect the distribution of species? Tick (✓) two boxes.[2]
A change in temperature
A change in the availability of water
A change in the number of genes in a species
A change in the scientific name of a species
A change in the size of the individual animals
(b) Environmental changes can be seasonal, geographic or caused by human interaction. Complete {table} by writing seasonal, geographic or human interaction for each example.[3]
[object Object]
Show the answer and mark scheme
(a)Answer: A change in temperature; A change in the availability of water
(b)Answer: Seasonal; geographic; human interaction
swallows: seasonal
alpine plant: geographic
fish: human interaction
Question 2Medium7 marks
Scientists recorded how far north a species of butterfly is found in Britain. {table} shows the distance of the northern edge of its range from the south coast, and the mean summer temperature in the south of Britain.
[object Object]
(a) Calculate the mean rate at which the northern edge of the range moved north between 1980 and 2020.[2]
(b) Suggest why the range of the butterfly moved north.[2]
(c) Environmental changes can be seasonal. Give one example of a seasonal change in the distribution of animals.[1]
(d) Another species of butterfly lives only in cold mountain areas. Suggest why its range may decrease as temperatures rise.[2]
Show the answer and mark scheme
(a)Answer: 5.5 km per year
(530 − 310) ÷ 40
5.5 (km per year)
(b)
the mean temperature increased (from 15.1 °C to 16.4 °C)
so areas further north became warm enough for the butterfly (or its food plants) to survive and breed
(c)
birds migrating to warmer areas in winter / returning in spring
animals moving to find water or food in the dry season
animals moving to lower ground in winter
(d)
lower slopes become too warm, so it can survive only higher up the mountain
there is less land at higher altitudes / it cannot move higher than the top of the mountain
Question 3Hard9 marks
An alpine plant species grows on a mountain with a summit at 2600 m.
In 1960 the plant was found from 1800 m up to the summit.
In 2020 it was found only from 2150 m up to the summit.
Over the same period, the mean annual temperature at 2000 m increased by 1.4 °C.
(a) Calculate the percentage decrease in the altitude range of the plant between 1960 and 2020.[2]
(b) Suggest why the plant is no longer found at lower altitudes.[2]
(c) A student concluded that global warming caused this change in distribution. Evaluate this conclusion.[3]
(d) Predict what will happen to the plant on this mountain if the temperature continues to rise. Explain your answer.[2]
Show the answer and mark scheme
(a)Answer: 43.75% (43.8%) %
ranges: 2600 − 1800 = 800 m and 2600 − 2150 = 450 m
(800 − 450) ÷ 800 × 100 = 43.75 (%)
(b)
lower altitudes became too warm for the plant
plant species from lower down moved up and outcompeted it
less snow cover / less water available at lower altitudes
(c)
the temperature increased as the plant moved up the mountain, which supports the conclusion
but a correlation does not prove causation
other factors could have changed, e.g. grazing / trampling by tourists / pollution / land use
only one species on one mountain was studied
there are data for only two years (1960 and 2020)
(d)
its range will get smaller / it may become extinct on this mountain