Activity 1

Questions
1. Figure 11.1 below shows the averages of carbon dioxide concentration in the atmosphere since January 2009, as measured at the Mauna Loa Observatory in Hawaii.

Figure 11.1: Average carbon dioxide concentration in the atmosphere since January 2009, at Mauna in Hawaii

1.1 Describe how deforestation could lead to an increase in the carbon dioxide concentration in the atmosphere.    (2)
1.2 Mention ONE human activity that might have led to the increase in carbon dioxide concentration as seen in the graph.  (1)
1.3 What was the carbon dioxide concentration in the atmosphere in July 2012?     (2)
1.4 What is the dependent variable in this investigation?         (1)
1.5 Explain how the excess carbon dioxide in the atmosphere could lead to climate change.    (4)
1.6 Mention ONE way in which humans can reduce the amount of carbon dioxide released into the atmosphere.    (1) [11]

Answers to activity 1
1.   
1.1 Cutting down of trees decreases the amount of carbon dioxide✔ taken up by the plants during photosynthesis✔    (2)
1.2 Burning of fossil fuels✔     (1)
1.3 393,5✔ ppm✔ (2)
1.4 Carbon dioxide concentration in ppm✔   (1)
Answers to activity 1 (continued)
1.5

• Carbon dioxide is a greenhouse gas✔
• which absorbs long wave radiation emitted from the Earth✔
• and prevents it from escaping back into the atmosphere✔.
• An increase in the concentration of carbon dioxide leads to an increase in the greenhouse effect✔,
• which may result in global warming✔. (any 4)

1.6

• Drive less✔/use public transport, walking, bicycle more
• Reduce the need for heating by insulating walls✔
• Building energy efficient homes✔
• Use alternative energy sources✔ (solar and wind)
• Reforestation✔to act as carbon reservoir
• Reuse and recycle✔ (any 1) [11]

Activity 2

Questions

1. An investigation to measure the ozone concentration and the chlorine levels has been done in Antarctica since 1950 and the results are shown in the graph below:

1.1 Give a caption for the graph.    (2)
1.2 What is the relationship between the levels of chlorine and the concentration of ozone?   (2)
1.3 Name the dependent variable(s) in the investigation.    (2)
1.4 In which 10-year period was the ozone depletion the greatest? (1)
1.5 In 1987 the Montreal Protocol was signed to lay down targets to reduce the use of CFCs by countries. Give TWO reasons why, despite a reduction in the use of CFCs, there was still a decline in the ozone layer.   (2)
1.6 Name ONE item that humans were using which contained CFCs.   (1)
1.7 Explain why the ozone layer is important for humans.      (2) [12]

Answers to activity 2

1.   
1.1 Changes in the levels of chlorine and ozone concentration✔ from 1950 to 1990✔  (2)
1.2 An increase in the level of chlorine ✔leads to a decrease in the ozone concentration✔   (2)
1.3

• Chlorine levels✔
• Ozone concentration✔ (2)

1.4 Between 1970 and 1980✔  (1)
1.5

• CFCs might persist for a long time in the atmosphere✔ 
• Other countries might have taken longer to implement the protocol✔
• Households were still using existing items with CFCs✔ (any)(2)

1.6

• Aerosols✔
• Refrigerators✔
• Food packaging✔   (any)(1)

1.7 The ozone layer provides protection against ultraviolet rays✔, thus reducing the chances of getting skin cancer✔         (2) [12]

Activity 3

Questions
1.  A group of learners conducted an investigation to determine the average amount of water used by a household for different purposes. They collected data on water-use from 5 families in their neighbourhood. The results are shown below.

1.1 Identify the:
a)  Dependent variable   (1)
b)  Independent variable (1)
1.2 State TWO ways in which the reliability of the results can be improved.      (2)
1.3 Draw a pie-chart to represent the data in the table. Show all calculations.   (7)
1.4 Describe ONE advantage of making the results of the survey available to the various households that participated.  (2) [13]

Answers to activity 3

1.1
a)  Average amount of water used✔   (1)
b)  Purpose for which water is used✔  (1)
1.2

• Repeat the investigation✔
• Select the households randomly✔
• Increase the number of households involved in the investigation✔  (any 2)

1.3 Calculations for proportions of slices in the pie-chart

Average amount of water used by a household for different purposes

(7)
1.4 Owners can identify the areas of greatest water use✔ to  allow them to then develop strategies to reduce water use in that area✔ (2) [13]

Activity 4

Questions
1.  Describe how alien plants may reduce both the availability and quality of water.  (4)
2.  Describe how poor farming practices may reduce both the availability and quality of water.   (4) [8]

Answers to activity 4

1.                            
   • Alien invasive plants may use water excessively✔ and thus reduce the amount of water available for the natural vegetation✔ of an area (2)
   • Alien invasive water plants block the waterways, reducing light to other aquatic plants✔. These plants eventually die and decompose✔. Bacteria that decompose these plants eventually deplete the oxygen supply in the water✔. (any) (2)
2.                                    
   • Over-grazing leads to soil erosion✔. On land that is eroded, water runs off rapidly rather than soaking into the ground✔, and is thus wasted. (2)
   • The use of fertilizers and pesticides may pollute nearby dams, ponds and rivers✔ thus reducing the quality of water available✔ (2) [8]

Activity 5

Questions
1.  Read the article below entitled ‘Durban to Recycle Sewage water into Drinking Water’.

1.1 List FIVE different strategies referred to in the article intended to increase the availability of clean drinking water.  (5)
1.2 Describe THREE arguments used in the article to convince the reader about the safety of recycled sewage water.    (6)
1.3 List THREE processes that will be used to ensure that the recycled sewage water will be fit for human consumption.   (3) [14]

Answers to activity 5

1.1

• Recycling sewage water✔
• Purifying sea water✔
• Replacing old, leaky pipes✔
• Reducing water pressure✔
• Building new dams✔ (5)

1.2

• No outbreak of water-borne diseases✔ in Windhoek for 42 years✔
• 3 safety barriers✔ to ensure the quality✔ of treated effluent
• Stored for at least 12 hours✔ allowing sufficient time for repeated testing✔ (6)

1.3

• Pumped at high pressure through ultra-filtration membranes✔  to remove suspended and dissolved solids and bacteria
• Filtration through tiny pores✔
• Ultra-violet disinfection✔ (3) [14]

Activity 6

Questions
1.  Study the table below and answer the questions that follow.

Adapted from CUP Biology: Jones and Jones, 2010
1.1 For Sub-Saharan Africa, calculate the food wastage by consumers as a percentage of the total food waste. (3)
1.2 Suggest a reason for this low percentage calculated in QUESTION 1.1 above. (2)
1.3 Explain the differences in the pattern of food wastage in developed and developing regions. (4)
1.4 State TWO possible ways of preventing the high levels of food waste that are found in the developed countries. (2) [11]
2. The following questions relate to the factors that threaten food security in a country.
2.1 Give ONE reason why there has been an increase in the demand for food over the years. (1)
2.2 State one way in which the use of each of the following helps to increase food productivity:
a) Pesticides (1)
b) Fertilizers (1)
2.3 Describe how the use of pesticides could destroy food chains. (2)
2.4 Explain why GMOs may be considered a threat to food security. (3) [8]

Answers to activity 6

1.
1.1 Food Wastage in Sub-Saharan Africa
5/160✔ × 100✔ = 3.1%✔ (3)
1.2 Access to food is scarce and the food that is available is either provided by international aid agencies or subsistence farming✔. Very little food is bought and even less is bought from supermarkets.✔ There is no food left over to waste.✔ (any 2)
1.3 In developed regions: buy food from markets, shops and supermarkets, often in excess of their requirements and will throw unused food away.✔ The markets, shops and
supermarkets will also throw away unsold food.✔
In developing regions: people will depend more on small, local sources of food,✔ have less food security and will not have food in excess of their needs.✔ (4)
1.4 Possible ways to reduce food waste include:

• Prevention - prevent consumers from throwing away food or stop them from producing/buying more food than they need✔
• Plan what you need before you shop and reduce impulse and spontaneous buying✔
• Understand how to store and preserve food✔
• Ensure that unused food is used in some way - e.g. give to the poor, animal feed, compost heaps.✔
• Education✔ (any 2) [11]

2. 2.1 There has been a rapid increase in the human population✔ (1)
2.2
a) Pesticides kill the pests which destroy the crops✔ (1)
b) Fertilizers increase nutrient content in the soil✔ (1)
2.3 Secondary consumers e.g. birds can eat the pests with the poison✔, which can kill the birds3 thereby decreasing the population size of birds✔
OR
The pest can become extinct✔, and the population size of the secondary consumer feeding on the pest will also decrease✔ (any 1 × 2) (2)
2.4

• Loss of flora and fauna biodiversity by inbreeding of GMOs✔
• Entire species could be wiped out✔ if exposed to diseases✔ (no variation in the population)/GMOs will have no resistance to the diseases (3) [8]

Activity 7

Questions
1.  Study the following table showing a summary of the rhino poaching incidents in South Africa from 2006 - 2010.

1.1 How many rhinos were illegally hunted in 2009?    (1)
1.2 Suggest THREE ways in which the poaching of rhinos can be stopped.    (3)
1.3 Describe the general trend observed in the table.   (2)
1.4 By what percentage did the poaching of rhino incidents increase in North West from 2008 to 2010? Show all working. (3)
1.5 Use the data in the table and draw a bar graph to show the number of rhinos poached each year from 2006 to 2010 in South Africa.  (7) [16]
2.  Read the following passage on Rooibos (Aspalanthus linearis) and answer the questions that follow.

2.1 Describe TWO ways in which over-exploitation of plants, such as Rooibos, impacts on other life forms and the environment. (2)
2.2 Describe THREE strategies that could be used to prevent the over-exploitation of plants such as Rooibos.  (3) [5]

Answers to activity 7

1.
1.1 122 ✔ (1)
1.2

• Rhino horns must be sawn off ✔
• Implant a ‘Pro Tag Device’ to monitor movement of the rhino ✔
• Institute heavy penalties like imprisonment instead of fines ✔ (3)

1.3 Rhino poaching ✔ has increased ✔ from 2008 to 2010 (2)
1.4 44✔  × 110 ✔ = 628,53% ✔  (3)
       7 ✔      1   ✔

1.5 

2.
2.1

• Plants can become extinct ✔/leads to loss of biodiversity
• Food chains/webs can be destroyed✔
• Could lead to degradation of the environment ✔
• Erosion of ground surface if too many plants are removed ✔
• Increase run-off of water ✔
• Alien plant invasion ✔in the habitats from which the plants are removed
• Upset the balance of oxygen and carbon dioxide ✔/global warming if too many plants are removed (any 2)

2.2

• Sustainable harvesting ✔
• Impose quotas ✔/limit numbers
• Limit area✔where plants are harvested
• Limit size of plants harvested ✔
• Limit time/seasons of collection ✔
• Research done to look at reproductive cycle✔/alternative source of active ingredient/cloning
• Legislation to control harvesting ✔
• Permits to control harvesting ✔
• Monitoring of harvest ✔
• Penalties ✔for breaking legislation
• Education ✔/campaign on the impact and consequences of over-exploitation
• Establish nurseries ✔/seed banks - to replace plants harvested
• Establish more nature reserves ✔ to conserve indigenous plants  (any 3) (5)

Activity 8

Questions
1.  State FOUR strategies you would use to manage solid waste if you were appointed as the head of the waste disposal division of your town.  (4)
2.  The following table shows the total amount of solid waste and the amount of recyclable material dumped in a South African city landfill site over a number of years.

2.1 Describe the general trend in the total amount of waste produced and the amount of recyclable materials dumped from 2003 to 2006.    (2)
2.2 Explain TWO advantages of recycling.   (4)
3.  The graph below shows the percentages of various types of waste found on the grounds of a school.

3.1 Draw a table to illustrate the percentages of waste shown in the graph above. (5)
3.2 The school wants to manage the large amount of wastegenerated on a daily basis. They decide to recycle the waste.
3.2.1 Define ‘recycling’. (2)
3.2.2 Give TWO reasons why the recycling of waste is advantageous. (2) [19]

Answers to activity 8

1.

• Investigate methods to collect and utilise methane gas as a fuel ✔
• Encourage citizens of the city to sort their waste ✔ into different waste containers
• Partner with recycling companies for improved collection of different wastes ✔
• Institute fines ✔ for people that do not separate the waste into different bins
• Educate people to use organic waste ✔ for example to make compost
• Encourage recycling ✔of items such as papers, tins, glass 
• Encourage citizens to reuse ✔ items such as glass
• Penalties/charge people extra if they generate more waste ✔ (any 4)

2. 2.1 Both ✔ the total amount of waste produced and the amount of recyclable material increased ✔ from 2003 to 2006 (2)
2.2

• People collect and sell waste at buy-back centres ✔ and therefore benefit economically ✔/create own jobs
• People who collect waste and take it to recycling depots✔ contribute to sustainable use of materials ✔
• Recycling saves energy ✔ and therefore reduces the amount of energy used to make new products ✔ (any 2 × 2) [4]

3.
3.1 Percentages/amount of each type of waste on the school grounds

3.2
3.2.1 The process by which waste materials✔are treated in such a way that they can be used again✔/ reused (2)
3.2.2

• To avoid over-exploitation of the limited natural resources✔
• To save/raise money✔/(create jobs)
• To reduce the amount of waste material✔/cleaner environment
• Less energy✔used/Reduce carbon footprint
• Fewer landfill sites✔ (any 2) (2) [19]