Human Effects On The Enviroment

Question 1

What is acid rain?

Answer 1

Rain with pollutants dissolved in it

Question 2

How was acid rain formed?

Answer 2

• sulphur dioxide, nitrogen monoxide and nitrogen dioxide release from cars and factories, dissolve in the atmospheric water vapour to form weak acids

Question 3

What damage can acid rain cause?

Answer 3

• Can dissolve limestone buildings

- decrease the ph of rivers and lakes and effect the enzymes and organisms in the river or lake

Question 4

What is the greenhouse affect?

Answer 4

Gases in the atmosphere act to trap radiated energy preventing it from escaping back into space this leads to more energy being held by the atmosphere leading to global warming

Question 5

What gases cause the greenhouse affect?

Answer 5

• water vapour
• CO2
• methane
• nitrous oxides
• CFCs

Question 6

How can you see that global warming has occurred?

Answer 6

• by looking at ice cores and fossilised tree rings

Question 7

What is the enhanced greenhouse effect?

Answer 7

Because the greenhouse effect is a natural effect of gases in the atmosphere, any extra greenhouse effect caused by human activity is called the enhanced greenhouse effect

Question 8

What causes CO2 to enter our atmosphere?

Answer 8

• Burning fossil fuels

- slash and burn forest clearance

Question 9

What causes methane to enter or atmosphere?

Answer 9

• cattle produce methane from anaerobic activity of bacteria in their gut
• bacteria in waterlogged paddy fields for rice cultivation give off methane

Question 10

What gives off nitrous oxides into our atmosphere?

Answer 10

• burning fossil fuels

Question 11

What causes CFCs to enter our atmosphere?

Answer 11

• they were used in aerosols

- they were used in fridges and freezers

Question 12

What are the potential effects of global warming?

Answer 12

• melting of polar ice caps = sea levels rise, which causes flooding
• destruction of habitats = extinction of species
• desertification = famine
• increase extreme weather events

Question 13

What affect does untreated sewage entering rivers cause?

Answer 13

Affect the number of microorganisms in the river, which has an affect on larger organisms

Question 14

Describe what happens when sewage enters a river

Answer 14

• sewage contains dead organic matter
• this is good for microorganism eg bacteria and fungi
• microorganisms reproduce
• they respire aerobically
• increases the biological oxygen demand, using up oxygen in the water
• fish die as lack of oxygen

Question 15

What is leaching?

Answer 15

something is washed out of soil

Question 16

What are the effects of leeched nitrates?

Answer 16

• nitrates from fertilisers are leached from the soil and enter a river
• The nitrates are absorbed by the algae
• these multiply rapidly and may completely cover the water this is called Algal bloom
• this blocks out sunlight for other plants
• this means they are unable to photosynthesise and die
• even the algae on top eventually die
• The dead remains provide a good source of food for bacteria
• bacteria multiply rapidly
• large population of bacteria respire aerobically increasing the biological oxygen demand, using up oxygen in the water
• decreases the level of oxygen for other organisms resulting in death other organisms as they cannot respire
• this process is called eutrophication