Human influences on the ecosystem

Question 1

Give 4 ways that modern technology has aided food production.

Answer 1

• New efficient machines can work over large areas
• Improved fertilisers to boost crop yield
• insecticides prevent crops from being destroyed by insects
• Herbicides stop competition from weeds for resources
• Desirable features chosen through selective breeding

Question 2

Give one reason why monoculture is so bad for the ecosystems.

Answer 2

Monoculturre reduces diversity sidnificantly.

Question 3

State the negative impacts of intensely farming livestock.

Answer 3

• Water pollution
• Soil and land quality is decreased
• Reduction in biodiversity

Question 4

State 2 social issues with providing sufficient food for a growing human population.

Answer 4

• Land used for agriculture could be used for housing or leisure facilities
• Machinery used for agriculture can be loud and may become an issue for people who live nearby

Question 5

State 2 economic issues with providing sufficient food for a growing human population

Answer 5

• Some less economically developed countries may not be able to establish efficient food production infrastructure
• More people will be living in harsher climates and therefore the cost of staple foods as imports will be greater

Question 6

State 2 environmental issues with providing sufficient food for a growing human population.

Answer 6

• Farming equipment and processing facilities can produce extra greenhouse gas emissions
• Monoculture decreases biodiversity

Question 7

State 4 factors that can lead to famine

Answer 7

• Natural disasters (flooding/drought)
• Unequal distribution of food
• Rapidly increasing population
• Poverty

Question 8

Describe 3 human activities that cause habitat destruction.

Answer 8

• Deforestation for timber production, housing and farming
• Extraction of natural resources requires clearing land and large machinery
• Marine pollution from oil spills, waste, eutrophication and plastic waste is damaging to aquatic life and the habitat they live in

Question 9

Describe how sewage in waterways can affect aquatic life.

Answer 9

Microorganisms that decompose sewage will use up the oxygen in the water so that there is not enough oxygen left for respiration for other aquatic organisms

Question 10

Give 4 undesirable effects of deforestation

Answer 10

• Extinction
• Erosion of soil
• Increased risk of flooding
• Increased atmospheric carbon dioxide

Question 11

Explain how deforestation causes extinction (Higher/Supplement)

Answer 11

• Deforestation removes food and shelter for animals

- Animals without food or shelter are less likely to survive, leading to extinctions

Question 12

Explain how deforestation leads to soil erosion

Answer 12

• Tree roots anchor soil and the trees shelter and protect the soil which prevents erosion
• Deforestation leaves the soil exposed and erosion happens more quickly

Question 13

Explain how deforestation leads to an increased risk of flooding

Answer 13

• Trees absorb water which evaporates off their leaves, leaving the ground drier and able to absorb more water
• Less trees increases surface runoff and the risk of flooding

Question 14

Explain how deforestation leads to increased carbon dioxide levels

Answer 14

• Trees take in carbon dioxide from the atmosphere during photosynthesis which decreases atmospheric carbon dioxide levels
• When trees are cut down, the atmospheric carbon dioxide is no longer absorbed and so level remain higher

Question 15

State 5 sources of water pollution

Answer 15

• Insecticides
• Herbicides
• Sewage
• Waste (plastics, chemicals, metal)
• Nuclear fallout

Question 16

State 4 sources of air pollution

Answer 16

• Vehicle exhaust
• Home heating
• Industrial fossil fuel burning for generating power
• Manufacturing processes

Question 17

State 4 sources of air pollution

Answer 17

• Vehicle exhaust
• Home heating
• Industrial fossil fuel burning for generating power
• Manufacturing processes

Question 18

State 4 sources of land pollution

Answer 18

• Agriculture
• Improper handling of waste
• Sewage leaks
• Industrial pollution (chemicals, paints, plastics)

Question 19

What is eutrophication?

Answer 19

An excess of nutrients in a body of water, often due to fertilisers in the water source

Question 20

Why is eutrophication bad for aquatic life?

Answer 20

It causes an ‘algal bloom’ which decreases oxygen supplies in the water and degrades the water quality

Question 21

Describe the process of eutrophication (

Answer 21

• Often caused by leaks of fertilisers containing nitrate and other ions into the water source
• Increased growth of producers (e.g. algae which is called an algal bloom)
• Increased decomposition after death of producers (due to lack of light) by decomposers which use up dissolved oxygen during respiration
• Organisms that need the oxygen in the water begin dying

Question 22

What is meant by non-biodegradable waste?

Answer 22

Waste which cannot be broken down naturally in the environment (e.g. by erosion or decomposers)

Question 23

Describe the effects of non-biodegradable plastics

Answer 23

• Chemicals in the plastics can leach out and cause damage to organisms
• Animals can get trapped in plastics, leaving them vulnerable (e.g. to predators or starvation)
• Animals can swallow plastics, causing blockages and often death

Question 24

State 3 sources of methane in the atmosphere

Answer 24

Biomass burning

• Livestock production systems
• Decaying matter in landfills

Question 25

What does excess atmospheric methane and carbon dioxide cause?

Answer 25

-Methane and CO2 are greenhouses gases
-Excess greenhouse gases lead to the
greenhouse effect where heat is trapped by the gases
-This leads to global warming

Question 26

State 3 negative consequences of global warming

Answer 26

• Sea level rise caused by melting iceberg
• Disrupted farming and agriculture
• Increased spread of diseases in warmer climate

Question 27

What detrimental impacts can sulfur dioxide have on the environment?

Answer 27

• Formed when fossil fuels containing impurities are burnt

- Sulfur dioxide can dissolve in water to form acid rain which can erode buildings and pollute water sources

Question 28

State 3 negative effects of acid rain

Answer 28

• Acid rain accumulates in waterways, polluting water and harming organisms
• Acid rain damages plants and trees
• Acid rain erodes buildings and infrastructure

Question 29

How is the amount of sulfur dioxide production reduced?

Answer 29

• Switch to renewable energy sources
• Sulfur dioxide can be removed from waste gases
• Sulfur impurities can be removed from fuels before they are burnt

Question 30

How can the impact of acid rain be reduced?

Answer 30

Reduce the acidity of soil and water by adding powdered limestone or slaked lime

Question 31

Explain how excess methane and carbon dioxide causes global warming

Answer 31

• The gases accumulate in the atmosphere and absorb the thermal energy from the sun
• This traps the extra heat energy in the atmosphere and warms the earth

Question 32

Describe the negative impacts of female contraceptive hormones in water supplies

Answer 32

• Oestrogens can change the behaviour of fish by altering their genes
• Contraceptive hormones can cause male fish to produce eggs and can no longer reproduce (feminisation)

Question 33

What is a sustainable resource?

Answer 33

A resource which is produced as rapidly as it is used up so that it does not run out

Question 34

What is sustainable development?

Answer 34

Development to meet the growing needs of the human population without damaging the environment

Question 35

Why is it necessary to conserve fossil fuels?

Answer 35

Because fossil fuels are non-renewable and so will run out with continued use

Question 36

State 2 resources that can be maintained

Answer 36

⦁ Timber

⦁ Fish stocks

Question 37

How can forests and fish stocks be sustained?

Answer 37

⦁ Teaching people about the need for conservation
⦁ Legal quotas that define a limit to the amount of fishing
⦁ Replanting trees when they have been cut down
⦁ Captive breeding programs

Question 38

State 4 resources that can be recycled

Answer 38

⦁ Paper
⦁ Glass
⦁ Plastic
⦁ Metal

Question 39

How can sustainable development be achieved? (

Answer 39

⦁ By managing conflicting demands (e.g. for resources by ensuring the use of resources does not damage the environment and resources are used in moderation)
⦁ By cooperating at local, national and international levels and implementing government schemes

Question 40

Give 5 causes of extinctions

Answer 40

⦁	Climate change
⦁	Destroying habitats
⦁	Hunting/poaching
⦁	Pollution
⦁	The introduction of a foreign species

Question 41

What are the risks to a species if the population size drops considerably?

Answer 41

⦁ A smaller population size means that there will be a smaller gene pool
⦁ A smaller gene pool means that the population are not able to adapt to change as easily and are at a higher risk of extinction

Question 42

Give 4 ways that species can be conserved

Answer 42

⦁ Monitoring and protecting species and habitats
⦁ Teaching people about why species are going extinct and how to prevent extinction
⦁ Captive breeding programmes within zoos and wildlife reserves with the aim of increasing the population size before reintroduction into the environment
⦁ Seed banks to preserve genetic diversity

Question 43

Why is conservation important?

Answer 43

⦁ It prevents the extinction of species
⦁ It protects vulnerable environments
⦁ It ensures that ecosystems can still provide useful resources like medicines and food