Human Impacts on the Enviroment

Question 1

What chemicals if released into the atmosphere cause acid rain?

Answer 1

• Sulphur Dioxide
• Nitrogen Monoxide
• Nitrogen Dioxide

Question 2

State the greenhouse effect

Answer 2

1. Sun emits radiation
2. Some are reflected by earth atmosphere but some passes through and is absorbed by the earth’s surface.
3. This warms the earth which then emits infrared radiation
4. Some IR radiation passes through the atmosphere into space but gases in the atmosphere absorb the IR radiation preventing it from escaping.
5. The more greenhouse gases in the atmosphere the more the earth is warmed
6. This is called the enhanced greenhouse effect

Question 3

What human activity produces CO2?

Answer 3

• Burning fossil fuels
• Slash and burn forest clearance

Question 4

What human activity produces methane?

Answer 4

• Cattle produce large volumes of methane from belching
• Bacteria in waterlogged paddy fields for rice cultivation give off methane

Question 5

What human activity produces Nitrous oxides?

Answer 5

• Burning fossil fuels

Question 6

What does CFC’s stand for?

Answer 6

• Chloro Fluro Carbons

Question 7

What do CFC’s do?

Answer 7

• Create holes in the ozone layer

Question 8

What are the potential effects of global warming?

Answer 8

• Melting of polar ice caps
• Destruction of habitats
• Drought and deforestation
• Increased number of extreme weather events
• Spread of disease
• Change in crops
• Increase in heat-related illness and deaths

Question 9

What causes deforestation?

Answer 9

• The increase in human population
• Development of machinery
• Means more trees are cut down
• Rainforests are resource-rich

Question 10

What is the cleared space in the rainforests used for?

Answer 10

• Cattle farming
• Rice fields
• Growing crops for biofuels

Question 11

What are the effects of deforestation?

Answer 11

• Soil Leaching
• Eutrophication
• Soil Erosion
• Carbon Sink removed, less CO2 absorbed by trees via the process of photosynthesis

Question 12

State the carbon cycle

Answer 12

Question 13

State the Nitrogen cycle

Answer 13

1. Plant or Animal dies its tissues decompose
2. Molecules containing nitrogen such as proteins are broken down and ammonia is released into the soil
3. Ammonia is converted to nitrates and nitrites by nitrifying bacteria. This is called Nitrification.
4. Plant roots absorb nitrates.
5. Some nitrates are converted into Nitrogen by denitrifying bacteria. This process is called denitrification

Question 14

What is Decomposition and what bacteria are involved?

Answer 14

• Protein in dead plants and animals is broken down
• Ammonia is released into the soil
• Decomposing bacteria

Question 15

What is Nitrification and what bacteria are involved?

Answer 15

• Ammonia is converted to nitrates
• Nitrifying bacteria

Question 16

What is Denitrification and what bacteria are involved?

Answer 16

• Nitrates are converted to nitrogen gas (denitrification reduces the amount of nitrate in the soil and therefore makes soil less fertile)
• Denitrifying bacteria

Question 17

What is nitrogen fixation and what bacteria are used?

Answer 17

• Nitrogen gas is converted to ammonia in bacteria which is used to make proteins
• Nitrogen-fixing bacteria

Question 18

Where are Nitrogen-fixing bacteria found?

Answer 18

• In the soil
• And legumes which are the root nodules of plants

Question 19

What happens when lots of fertiliser is present on farmland and it rains?

Answer 19

• Washed out of the soil and gets into rivers

Question 20

How do decomposers break down dead material?

Answer 20

• Release enzymes
• Break down the material into smaller molecules
• release CO2 by respiration