Human Influences on Ecosystems
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Food supply and habitat destruction
SubtopicFood supply and habitat destruction under Human Influences on Ecosystems for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Which of these is a way to reduce the negative impact of human activities on ecosystems?
A.Increasing the use of single-use plastics
B.Expanding monoculture farming
C.Establishing protected areas and nature reserves
D.Increasing the burning of fossil fuels
- 2.
Why does deforestation often lead to an increase in flooding downstream?
A.Trees normally pump water into the ground.
B.Without trees, less water is absorbed by the soil and more runs off into rivers.
C.Dead trees block the rivers and cause them to overflow.
D.Deforestation causes more rain to fall.
- 3.
What is the main environmental risk of using genetically modified (GM) crops that are resistant to herbicides?
A.The crops will die if herbicide is sprayed on them.
B.The resistance gene might spread to wild weeds, making them harder to kill.
C.The crops will produce less food than non-GM crops.
D.The crops will require more water to grow.
- 4.
Which of the following is a benefit of crop rotation?
A.It requires more chemical fertilizers.
B.It helps to prevent the buildup of specific pests and diseases.
C.It uses the same minerals from the soil every year.
D.It allows the farmer to use the same machinery for everything.
- 5.
How does the reduction of 'leaf litter' due to forest clearing affect the soil's water-holding capacity?
A.It increases it, as there is more room for water
B.It decreases it, as organic matter (humus) helps to retain moisture in the soil
C.It has no effect on water retention
D.It makes the soil more like a sponge
- 6.
Which of these contributes most to the destruction of coral reef habitats?
A.The natural migration of whales
B.Increased sedimentation and rising ocean temperatures due to human activity
C.The presence of too many primary producers like seaweed
D.The decrease in the salt concentration of the ocean
- 7.
What is a major environmental disadvantage of converting natural grasslands into large-scale wheat farms?
A.Wheat plants produce too much oxygen
B.The loss of native plant and animal species that were adapted to the grassland
C.Wheat farming requires the removal of all from the atmosphere
D.The wheat attracts too many herbivorous mammals
- 8.
The 'Anthropocene' is a proposed geological epoch defined by human influence. In terms of 'Food Supply,' what is the most significant 'stratigraphic marker' left by modern humans?
A.The global distribution of chicken bones and plastics from food packaging
B.The presence of ancient wheat pollen in North American soil layers
C.The reduction in the amount of volcanic ash in the atmosphere
D.The increase in the number of fossilized dinosaur remains
- 9.
Which factor of habitat destruction most directly leads to an increase in 'Invasive Species' within an ecosystem?
A.The loss of topsoil through erosion
B.The creation of disturbed 'edge' habitats and the removal of native competitors
C.The increase in atmospheric concentrations
D.The use of organic fertilizers in neighboring farms
- 10.
The use of 'pesticides' can lead to 'Bioaccumulation' in an individual organism over its lifetime. How does this differ from 'Biomagnification'?
A.Bioaccumulation is the increase in toxin concentration across different trophic levels
B.Biomagnification is the increase in toxin concentration in a single organism as it ages
C.Bioaccumulation refers to the buildup within a single organism, whereas biomagnification refers to the increase up the food chain
D.There is no difference; the two terms are interchangeable in environmental biology
Download the worksheet for Human Influences on Ecosystems - Food supply and habitat destruction to practice offline. It includes additional chapter-level practice questions.
Pollution (Greenhouse effect)
SubtopicPollution (Greenhouse effect) under Human Influences on Ecosystems for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
What happens to the global climate when the concentration of greenhouse gases in the atmosphere decreases significantly?
A.The global temperature would likely decrease
B.The global temperature would likely increase
C.The oceans would boil
D.The Sun would get brighter
- 2.
Which of the following describes the effect of greenhouse gases on the 'heat budget' of the Earth?
A.They increase the amount of heat escaping to space
B.They decrease the amount of solar radiation reaching the surface
C.They reduce the amount of heat energy that leaves the Earth's system
D.They have no effect on the heat budget
- 3.
Which gas is produced as a byproduct of the combustion of gasoline in car engines?
A.Helium
B.Carbon dioxide
C.Ammonia
D.Phosphine
- 4.
What is the primary goal of international agreements like the Paris Agreement in relation to the greenhouse effect?
A.To eliminate the atmosphere
B.To limit the increase in global average temperature
C.To stop all forms of transportation
D.To increase the production of fossil fuels
- 5.
In a hypothetical ecosystem, if the temperature rises by , which species is most likely to face extinction?
A.A generalist species that eats many types of food
B.A species with a narrow range of temperature tolerance (stenotherm)
C.A species that can migrate long distances easily
D.A species that reproduces very quickly
- 6.
Which of the following is NOT a direct consequence of the enhanced greenhouse effect?
A.Rising sea levels
B.Increased skin cancer rates from UV radiation
C.Loss of habitat for polar species
D.More frequent and intense heatwaves
- 7.
Which process contributes most to the seasonal fluctuations in levels observed in the Northern Hemisphere?
A.Volcanic eruptions occurring in winter
B.The balance between photosynthesis and respiration in forests
C.Changes in the number of cars driven during the holidays
D.The freezing and thawing of the Arctic Ocean
- 8.
Which of these factors has the greatest uncertainty in current climate models regarding the greenhouse effect?
A.The net effect of clouds (whether they provide more cooling by reflection or more warming by trapping heat).
B.The rate at which humans burn fossil fuels in the next ten years.
C.The exact melting point of ice at sea level.
D.The chemical formula of methane and its reaction with oxygen.
- 9.
Why is 'Afforestation' (planting trees where there were none) sometimes criticized as a climate solution compared to 'Reforestation'?
A.It can destroy existing high-albedo or high-biodiversity ecosystems like grasslands or peatlands.
B.Trees planted in new areas are genetically modified to release more .
C.New forests do not perform photosynthesis for the first 50 years of their life.
D.It is impossible for trees to grow in areas where they have not naturally existed before.
- 10.
What is the biological impact of 'Ocean Deoxygenation' caused by the greenhouse effect?
A.Warming water holds less dissolved oxygen, leading to 'dead zones' where aerobic marine life cannot survive.
B.Increased levels cause fish to grow larger because they have more gas to 'breathe'.
C.Marine plants grow faster because they prefer water with low oxygen and high nitrogen.
D.It causes the water to become more buoyant, making it harder for fish to swim to the bottom.
Download the worksheet for Human Influences on Ecosystems - Pollution (Greenhouse effect) to practice offline. It includes additional chapter-level practice questions.
Conservation
SubtopicConservation under Human Influences on Ecosystems for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Which of these is a way that governments can encourage conservation?
A.Giving subsidies for cutting down old-growth forests
B.Passing laws that make it illegal to hunt endangered species
C.Removing all taxes on single-use plastics
D.Closing all national parks to the public
- 2.
What does the term 'urbanization' refer to, which often negatively impacts local wildlife?
A.The process of planting new forests
B.The growth of cities and the conversion of rural land into urban areas
C.The protection of marine life in the ocean
D.The process of recycling paper
- 3.
Which of these describes a 'threatened' species?
A.A species that is already extinct
B.A species whose population is so large it causes problems
C.A species that is at risk of becoming endangered in the near future
D.A species that only lives in a zoo
- 4.
What is the primary reason why bees are important for many ecosystems?
A.They produce honey for humans
B.They pollinate many plants, allowing them to reproduce
C.They keep other insects away from the forest
D.They help to break down large rocks
- 5.
What is the primary role of education in the conservation of endangered species?
A.To teach people how to hunt animals more efficiently.
B.To increase public understanding of the importance of biodiversity and encourage sustainable behavior.
C.To provide the scientific names of all species to every citizen.
D.To discourage people from visiting national parks.
- 6.
In a sustainable forest, why are dead trees (snags) sometimes left standing rather than being removed?
A.To prevent the growth of new, healthy trees.
B.To provide nesting sites and food sources for various birds and insects.
C.Because they continue to perform photosynthesis for several years.
D.To increase the risk of forest fires which help some seeds germinate.
- 7.
Which human activity is the primary cause of 'habitat fragmentation' in temperate regions?
A.The construction of roads and expansion of agricultural land.
B.The planting of community gardens in urban centers.
C.The use of organic fertilizers on small farms.
D.The migration of humans from cities to rural villages.
- 8.
Why is the use of 'Native Species' preferred over 'Non-native' species in habitat restoration projects?
A.Native species always grow faster than non-native species.
B.Native species have co-evolved with the local environment and other species, maintaining complex ecological interactions.
C.Native species are easier to buy from commercial nurseries.
D.Non-native species are incapable of performing photosynthesis in a different climate.
- 9.
Sustainable use of resources is often hindered by the 'Tragedy of the Commons.' Which scenario best illustrates this principle?
A.A private landowner protecting a forest for future timber use.
B.Individual fishers overexploiting a shared, unregulated fishing ground to maximize personal gain, leading to the collapse of the fish stock.
C.A government nationalizing all land to prevent development.
D.A community-managed garden where rules for harvesting are strictly followed.
- 10.
What is the biological significance of 'Genetic Drift' in the management of a captive population of a dozen individuals?
A.It increases the adaptive potential of the population.
B.It can lead to the random loss of beneficial alleles regardless of their selective advantage.
C.It ensures that the most fit individuals always survive and reproduce.
D.It prevents the population from becoming too large for the enclosure.
Download the worksheet for Human Influences on Ecosystems - Conservation to practice offline. It includes additional chapter-level practice questions.