Human influences on the environment Flashcards
When fossil fuels are burnt without enough air supply, what is produced?
Carbon monoxide CO
Why is carbon monoxide poisonous?
If it combines with haemoglobin in red blood cells, it prevents them from carrying oxygen
What is the biggest contributor of carbon monoxide?
Cars
Why are catalytic converters fitted to modern cars?
They turn the carbon monoxide into carbon dioxide therefore decreasing the amount of CO2 released into the atmosphere
What causes acid rain?
It is caused by sulphur dioxide. Sulphur dioxide and carbon dioxide are released when fossil fuels are burned
Where does the sulphur dioxide come from?
Sulphur impurities in the fossil fuels
How is acid rain formed?
When the gases mix with rain clouds, it forms dilute sulphuric acid which falls as acid rain
What are the main causes of acid rain?
Internal combustion engines in cars
Power stations
How does acid rain kill fish?
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
How does acid rain kill trees?
The acid damages leaves and releases toxic substances from the soil, making it hard for the trees to take up nutrients
What is the greenhouse effect?
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.
What do greenhouse gases do?
Trap energy from the Sun
Name some greenhouse gases?
Water vapour
Carbon dioxide
Methane
CFCs
Nitrous oxide
What is the effect of the Earth heating up known as?
Global warming
What other changes could global warming lead to?
Extreme weather
Rising sea levels
Flooding due to polar ice caps melting
Habitat loss which could affect food webs and crop growth
How are humans producing carbon dioxide?
Car exhausts
Industrial processes from burning fossil fuels
Deforestation
How is methane produced?
Methane is produced naturally from rotting plants in marshland
Rice growing and cattle rearing
Where does nitrous oxide come from?
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
Where does CFCs come from?
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.
How can fertilisers cause problems for the environment?
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.
Apart from fertilisers what is another cause of eutrophication?
Sewage. Sewage contains phosphate from detergent and nitrates from urine and faeces.
What are three negative effects of deforestation?
Soil
Evapotranspiration
Carbon cycle
Explain the negative effects of leaching
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.
Explain the negative effect of soil erosion?
Tree roots hold the soil together, when the trees are removed the soil can be washed away, leaving the ground infertile
