B2g - population and pollution

Question 1

How and why is the human population growing(2)

Answer 1

Increasing exponentially

Due to the birth rate exceeding the death rate

Question 2

Describe the causes and consequences of global warming (2)

Answer 2

Caused by CO2 from burning fossil fuels which is a greenhouse gas that keeps more heat in atmosphere, leading to increased global temperature

Causes sea level rise, less predictable weather systems, lower agricultural output

Question 3

Describe the causes and consequences of acid rain (4)

Answer 3

Caused by sulfur dioxide from burning fossil fuels reacting with water in the atmosphere to form sulfuric acid which comes down as rain

Kills trees

Corrodes limestone ruining buildings and statues

Kills animals which are sensitive to changes in pH or cannot live in more acidic conditions

Question 4

Describe the causes and consequences of ozone depletion (2)

Answer 4

Caused by CFCs released from aerosols breaking down ozone in upper atmosphere

Allows more harmful UV rays to reach surface, leading to:

• increased risk of skin cancer
• reduce in fish levels

Question 5

Who has the greatest impact on pollution and use of resources(2)

Answer 5

the developed countries of the world with a small proportion of the world’s population

use more resources and pollute more per capita, creating more pollution

Question 6

What is carbon footprint

Answer 6

the amount of greenhouse gases given off in a certain period of time

Question 7

Discuss the possible consequences of exponential

growth(3)

Answer 7

shortage of food in some countries

more pollution being produced

the world’s resources (e.g. fossil fuels and minerals) being used up fast

Question 8

How can pollution be measured(2)

Answer 8

by direct measurement of pollutant levels

by measuring the occurrence of indicator species

Question 9

Describe how indicator species can be used to estimate water quality(3)

Answer 9

mayfly larvae - the cleaner the water, the more survive

presence of water louse indicates high level of pollution

sludgeworms and red tailed maggots indicates very high level of pollution

Question 10

Describe how indicator species can be used to estimate air quality

Answer 10

lichens - the cleaner the air, the greater the diversity of lichens that survive

Question 11

Describe the advantages and disadvantages of using living methods of measuring levels of pollution (2+1)

Answer 11

Advantage:

• relatively quick, cheap and easy way since no expensive equipment or highly trained workers needed
• can monitor level over a long period of time

Disadvantage:
-unreliable since factors other than pollution (e.g. temp) can influence the survival of indicator species

Question 12

Describe the advantages and disadvantages of using non-living methods of measuring levels of pollution (2+1)

Answer 12

Advantages:

• produces reliable numerical data that’s easy to compare between diff sites
• exact pollutants can be identified

Disadvantages:
-require more expensive equipment and trained workers