Human Influences On The Environment

Question 1

What are the consequences of pollution by CO?

Answer 1

CO binds to haemoglobin in the red blood cells – prevents them from carrying oxygen.
Cars have catalytic converters that turn CO into Co2.

Question 2

What are the consequences of pollution by sulphur dioxide?

Answer 2

Burning fossil fuels releases sulphur dioxide – comes from impurities in fossil fuels.
Sulphur dioxide mixes with rain clouds – forms dilute sulphuric acid.
This falls as acid rain – main causes are combustion engines.

Question 3

What are examples of greenhouse gases?

Answer 3

Carbon dioxide
CFC’s
Methane
Nitrous oxide
Water vapour

Question 4

What are the effects of acid rain?

Answer 4

Cause lake to become more acidic.
Many organisms sensitive to pH & can’t survive.

Acid rain kills trees & releases toxic substances into soil - reduced nutrient uptake.

Question 5

How do human activities release GHG’s?

Answer 5

Co2 - burning fossil fuels
Methane - cows & rice growing
Nitrous oxide - vehicle engines
CFC’s - aerosols & fridges

Question 6

What happens with an increase of GHG’s?

Answer 6

Enhanced greenhouse effect - more heat trapped in the atmosphere - global warming.

Question 7

What are the consequences of global warming?

Answer 7

Extreme weather
Rising sea-levels & flooding - polar ice caps melting - habitat loss.

Question 8

What are consequences of water pollution by sewage?

Answer 8

Sewage contains many phosphates & nitrates - cause eutrophication.

Question 9

What happens if too much fertiliser is applied & it rains?

Answer 9

Nitrates easily leached (washed through the soil) into rivers & lakes - eutrophication.

Question 10

Explain eutrophication?

Answer 10

Fertilisers enter water - adding extra nutrients.
Nutrients cause algae to grow fast & blockout sunlight.
Plants can’t photosynthesise & start to die.
Microorganisms increase & use up all the oxygen.
Organisms that need oxygen die.

Question 11

Describe how deforestation causes leaching?

Answer 11

Trees take up nutrients before they can be washed away.
No trees mean nutrients leached away & don’t get replaced - infertile soil.

Question 12

Describe how deforestation affects the balance of atmospheric gases?

Answer 12

Trees burnt - co2 released at once - global warming.
Less photosynthesis - less oxygen.

Question 13

Describe how deforestation causes soil erosion?

Answer 13

Tree roots hold soil together.
No trees mean soil washed away - infertile ground.

Question 14

Describe how deforestation disturbs evapotranspiration?

Answer 14

No trees - less water evaporates - local climate drier.