Human influences on the environment

Question 1

When fossil fuels are burnt without enough air supply, what is produced?

Answer 1

Carbon monoxide CO

Question 2

Why is carbon monoxide poisonous?

Answer 2

If it combines with haemoglobin in red blood cells, it prevents them from carrying oxygen

Question 3

What is the biggest contributor of carbon monoxide?

Answer 3

Cars

Question 4

Why are catalytic converters fitted to modern cars?

Answer 4

They turn the carbon monoxide into carbon dioxide therefore decreasing the amount of CO2 released into the atmosphere

Question 5

What causes acid rain?

Answer 5

It is caused by sulphur dioxide. Sulphur dioxide and carbon dioxide are released when fossil fuels are burned

Question 6

Where does the sulphur dioxide come from?

Answer 6

Sulphur impurities in the fossil fuels

Question 7

How is acid rain formed?

Answer 7

When the gases mix with rain clouds, it forms dilute sulphuric acid which falls as acid rain

Question 8

What are the main causes of acid rain?

Answer 8

Internal combustion engines in cars
Power stations

Question 9

How does acid rain kill fish?

Answer 9

Acid rain can cause a lake to become acidic, this has a severe effect on the ecosystem, many organisms cannot live in more acidic conditions so the animals and plants die

Question 10

How does acid rain kill trees?

Answer 10

The acid damages leaves and releases toxic substances from the soil, making it hard for the trees to take up nutrients

Question 11

What is the greenhouse effect?

Answer 11

Trap energy from the Sun. The gases absorb most of the heat that would normally be radiated out into space, they re-radiate it in all directions including back towards the Earth.

Question 12

What do greenhouse gases do?

Answer 12

Trap energy from the Sun

Question 13

Name some greenhouse gases?

Answer 13

Water vapour
Carbon dioxide
Methane
CFCs
Nitrous oxide

Question 14

What is the effect of the Earth heating up known as?

Answer 14

Global warming

Question 15

What other changes could global warming lead to?

Answer 15

Extreme weather
Rising sea levels
Flooding due to polar ice caps melting
Habitat loss which could affect food webs and crop growth

Question 16

How are humans producing carbon dioxide?

Answer 16

Car exhausts
Industrial processes from burning fossil fuels
Deforestation

Question 17

How is methane produced?

Answer 17

Methane is produced naturally from rotting plants in marshland
Rice growing and cattle rearing

Question 18

Where does nitrous oxide come from?

Answer 18

It is released naturally by bacteria and soils in the ocean
A lot more released from soil after fertiliser is used
Vehicle engines and industry

Question 19

Where does CFCs come from?

Answer 19

Man-made chemicals once used in aerosol and fridges. CFCs damage the ozone layer and prevent UV radiation from reaching the Earth. Most countries have agreed not to produce them now.

Question 20

How can fertilisers cause problems for the environment?

Answer 20

Fertilisers can leach into water and cause eutrophication. Nitrates and phosphates put onto fields as mineral fertilises can be washed into rivers and lakes when it rains, this damages the ecosystems. The extra nutrients can cause algae to grow fast and block out the light which stops other plants photosynthesising. Other plants grow too fast and use up all the oxygen so there is no oxygen left for the fish.

Question 21

Apart from fertilisers what is another cause of eutrophication?

Answer 21

Sewage. Sewage contains phosphate from detergent and nitrates from urine and faeces.

Question 22

What are three negative effects of deforestation?

Answer 22

Soil
Evapotranspiration
Carbon cycle

Question 23

Explain the negative effects of leaching

Answer 23

Trees take up nutrients in the soil before they are washed away by rain and return them to the soil when leaves die. If the trees are removed, the nutrients are leached away and do not get replaced leaving the soil infertile.

Question 24

Explain the negative effect of soil erosion?

Answer 24

Tree roots hold the soil together, when the trees are removed the soil can be washed away, leaving the ground infertile

Question 25

Explain the problems of disturbing the balance of carbon dioxide and oxygen?

Answer 25

Forests take up CO2 by photosynthesis and it is slowly released when the trees die and decompose. When the trees are cut down and burnt the stored carbon is released at once as CO2 which disturbs the carbon cycle and contributes to global warming. Fewer trees in the forest means less photosynthesis which causes the oxygen levels in the atmosphere to drop.

Question 26

Explain the problems of disturbing evapotranspiration

Answer 26

Evaporanspiration includes both water evaporating from the Earth surface and plant transpiration. This waterfalls back to the Earth as rain. When trees are cut down evapotranspiration is reduced which can make the local climate drier.