Human Influences on the Environment

Question 1

What are the biological consequences of sulphur dioxide? (3)

Answer 1

• Released when fossil fuels are burnt
• Dissolves in water droplets in clouds
• Acid rain is created

Question 2

What are the consequences of acid rain? (3)

Answer 2

• Leads to aquatic organisms dying
• Corrodes metals and limestone in buildings
• Leeches minerals out of soil (plants and trees cannot survive)

Question 3

What are the consequences of carbon monoxide? (4)

Answer 3

• Released when fossil fuels are burnt incompletely
• Binds irreversibly to haemoglobin which reduces the capacity of oxygen a red blood cell can carry
• Leads to tiredness, unconsciousness
• In pregnant women, can affect the grow of a fetus

Question 4

Define greenhouse gases (3)

Answer 4

• Gases that absorb infrared radiation from the Sun
• Trapping above the Earth’s surface
• Leading to global warming

Question 5

Name 5 greenhouse gases and their origins

Answer 5

• Water vapour: rivers, lakes
• Carbon dioxide: deforestation, fossil fuels
• Nitrous oxide: fertilisers, vehicle engines
• Methane: cattle, rice paddy fields
• CFCL refrigerators, aerosol sprays

Question 6

What are the main effects of global warming? (3)

Answer 6

• Climate change
• Water levels rise because glaciers melt
• Loss of habitats

Question 7

What are the consequences of pollution of water by sewage? (4)

Answer 7

• Sewage: rich in materials and nutrients (that allow decomposers and algae to thrive)
• Decomposers (and sometimes bacteria) respire aerobically (using oxygen) to break down sewage
• The algae bloom stops light from reaching aquatic plants, causing them to die
• These lead to oxygen depletion, so other aquatic organisms will die

Question 8

What are the consequences of eutrophication? (3)

Answer 8

• Fertilisers are washed off from the land into nearby rivers by the rain
• Excess nutrients are washed into the lakes, encouraging rapid growth of algae
• Algae blocks sunlight, so aquatic plants cannot photosynthesise, leading to oxygen deprivation then the death of marine life

Question 9

Define deforestation

Answer 9

The clearing of an area of trees on a mass scale

Question 10

Describe the negative effects of deforestation (4)

Answer 10

• Leaching: trees normally take up nutrients and minerals from the soil for growth, without them, these run into bodies of water
• Soil erosion: tree roots normally stabilise the soil, without them, the soil will be washed away by the rain
• Disturbance of cycles: carbon cycles, water cycles
• Imbalance in oxygen and carbon dioxide: removal of trees will result in more atmospheric carbon dioxide levels and lower oxygen levels