3 Any other valid point. land, metal ores, fossil fuels, wood. 2 b Any five from:

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1 B8. The human population explosion a Any three from: 3 Any other valid point. ability to farm/fish, ability to cure or prevent diseases, no natural predators, ability to control environment by heating/lighting b buildings and roads farming quarrying dumping waste 2 a Any three from: 3 Any other valid point. land, metal ores, fossil fuels, wood. 2 b Any five from: 5 Any other valid point. use of electricity for lighting/heating/entertainment increased food production improved medicines use of fossil fuels for transport development of plastics improved waste disposal improved sanitation 3 Points may include: increased waste including bodily waste, industrial waste, packaging, uneaten food, and disposable goods exhaust gases from transport use of pesticides and fertilisers in farming. 6 Any other valid point. Oxford University Press This resource sheet may have been changed from the original.

2 B8.2 Land and water pollution a human bodily waste and waste water b toxic chemicals can spread from waste into soil, toxic chemicals can be washed into waterways, sewage can pollute soil with dangerous chemicals and gut parasites, toxins build up in organisms along food chain (bioaccumulation), largest predators die or are infertile due to toxic chemical build up c to monitor pollution levels in waterways 2 a i Points may include: 3 pesticides and herbicides spread from crops into soil plant material contaminated with toxins small levels of toxins taken in by animals eating affected plant material toxins build up along food chains (bioaccumulation) until toxic levels are reached in top predators. 2 a ii Points may include: Fertilisers washed from the soil into streams, ponds, and rivers. Nitrates in fertilisers encourage the rapid growth of algae and water plants. Microorganisms feeding on the plants use up oxygen decreasing the levels of oxygen. Other oxygen-dependent organisms then die because of a lack of oxygen. 3 Oxford University Press This resource sheet may have been changed from the original. 2

3 2 b Points may include: DDT in pesticide contaminated soil and waterways, organisms contaminated with toxins, DDT builds up in organisms along food chain, DDT levels become dangerously high in top predators (birds of prey, herons), effects of DDT not noticeable until dangerous levels reached, route through food chain not obvious. 6 Any other valid point. Oxford University Press This resource sheet may have been changed from the original. 3

4 B8.3 Air pollution a acidic gases released into atmosphere and spread around by wind b sulfur dioxide and nitrogen oxides dissolve into rain and snow, contaminating lakes/rivers/streams c dilute sulfuric acid and nitric acid fall as acid rain and soak into soil 2 a flow chart should include: 5 cars/power stations burn fossil fuels acidic gases (e.g., sulfur dioxide, nitrogen oxides) formed gases carried in the winds in atmosphere sulfur acidic gases dissolve in rainwater and react with oxygen to form dilute sulfuric acid and nitric acid acid rain falls 2 b Sulfur dioxide and nitrogen oxides can be carried high in air by winds. Acidic gases can be blown from a country that does not control its sulfur emissions to a country that has strict emission controls and fall as acid rain. 3 a = , 00 = 80, reduction of 80% 3 b Any two from: more efficient catalytic converters in cars, cleaner fuels, legislation to control emissions from factories. 3 c levels of acid rain should fall as sulfur dioxide emissions fall, unless prevailing winds carry acidic gases from non-european countries 2 Any other valid point. Oxford University Press This resource sheet may have been changed from the original. 4

5 4 a i 850: 0 million tonnes, 975: 4 million tonnes, 4 million tonne increase 4 a ii 975: 4 million tonnes, 2000: 8 million tonnes, 6 million tonne decrease 4 b Figure 2b shows increasing global sulfur dioxide emissions, causing increasing acid rain. Acid rain directly damages plant life by falling on plants and by soaking into soil and being taken up by roots. Acid rain contaminates soil and watercourses, making them more acidic and eventually unable to sustain life. Increasing sulfur dioxide levels threaten to reduce global biodiversity as whole ecosystems can be destroyed. Oxford University Press This resource sheet may have been changed from the original. 5

6 B8.4 Deforestation and peat destruction a removal of large areas of forest by felling/burning without trees being replaced b Tropical rainforests contain more biodiversity than any other land environment. Loss of orests means biodiversity of plant and animal life is also lost as habitats are destroyed and species become extinct. Many species are being destroyed before being identified and studied, so potential new sources of medicine or food could be lost. 2 carbon dioxide produced by burning of trees, carbon dioxide produced by decomposition of dead vegetation, less carbon dioxide removed from atmosphere by growing plants 3 a use of peat as fuel and by gardeners as compost 3 b CO 2 is released into atmosphere as peat is burnt or used as compost, increasing atmospheric levels of carbon dioxide and depleting the carbon store. Destruction of peat bogs destroys habitats and reduces biodiversity. 4 Points may include: cheap compost needed by gardeners and horticulturists to improve soil properties, promote seed germination, and increase food production; alternative, peat free composts are available but are less popular; peat bogs and peatlands vital to biodioversity as they form habitat for many organisms adapted to live in acidic conditions; peat forms very slowly and under very specific conditions cannot be replaced as quickly as it is being used. 6 Any other valid point. Oxford University Press This resource sheet may have been changed from the original. 6

7 B8.5 Global warming a Correct y-axis label and scale, Correct x-axis label and scale, data plotted correctly b carbon dioxide levels rising steadily over time, partly as a result of human activities c Energy transferred from Sun to Earth. Much of this heat is reflected back into space, but some is absorbed by greenhouse gases in the atmosphere and reradiated back to Earth. Earth s surface and atmosphere are warmed (greenhouse effect), maintaining conditions ideal for life. 2 a Atmospheric levels of greenhouse gases increasing as a result of human activity, increasing greenhouse effect and causing global temperatures to rise 2 b Any two from: loss of habitat reducing biodiversity changes in distribution some organisms may disappear from some areas as habitat changes changes in migration patterns caused by changes in climates and seasons reduced biodiversity some organisms will become extinct as climate changes 3 Accept any well-researched example and explanation. 6 4 Maximum of 2 marks per consequence. mark for consequence and mark for further explanation. Oxford University Press This resource sheet may have been changed from the original. 7

8 B8.6 The impact of change a i natural changes in environmental factors such as temperature, rainfall level, water availability, dissolved gases in water, and daylight hours between different seasons in temperate parts of the world a ii natural changes in environmental factors such as soil structure or ph, altitude, water salinity, and water availability between different geographical areas of the world b Natural mutations cause features that enable some individuals within a population to cope better with a change to their environment. These individuals are more likely to survive and breed (natural selection), passing on the beneficial feature to offspring. 2 a of breeding pairs of Dartford warblers in UK increasing 2 b Dartford warblers cannot survive very cold winters. Number of breeding pairs dropped sharply in 963, suggesting cold winter that reduced population. Number increased sharply in 200, perhaps as a result of temperature increase. Oxford University Press This resource sheet may have been changed from the original. 8

9 Question 2 c Temperature changes. Changes in of Dartford warblers indicate that s have increased as UK temperatures have increased but drop sharply after cold winters. Drop in of Dartford warblers in Spain indicates that too high a temperature also affects distribution. Evidence suggests that change in mean UK temperature and seasonal extremes of temperature affect distribution of UK birds both within the country and between countries. Answer Marks Guidance Oxford University Press This resource sheet may have been changed from the original. 9

10 B8.7 Maintaining biodiversity a important for environmental health, Any other valid point. offers potential source of new food crops, offers potential source of new medicines b breeding programmes for endangered species restoring endangered species to sustainable populations, protection and regeneration of rare habitats protecting different animals and plants, reintroduction of field margins and hedgerows allowing biodiversity to be maintained in agricultural land, reduction of deforestation maintaining habitats, recycling resources reducing habitat loss and pollution c Any one from: 4 Any other valid point. increased field margins limiting land available for food production, reduction of deforestation limiting land available for food production, taxes on landfill waste increasing costs to businesses. 2 a levels have fallen steadily 2 b Data suggests that Kyoto agreement drove UK government to take action to limit carbon dioxide emissions and that government intervention via legislation has been successful. Oxford University Press This resource sheet may have been changed from the original. 0

11 2 c Points may include: reduce or prevent increase in greenhouse effect and global warming maintaining biodiversity by preserving Arctic and Antarctic ice habitat, preventing rises in sea levels that will destroy biodiverse mangrove forests, preventing temperature increase that could dry out wetlands and 6 Any other valid point. cause bleaching/death of coral reefs. 3 Data shows that as landfill tax increased, amount of material going into landfill fell. Taxes on waste and emissions can be used as an effective incentive to change human habits and promote research into less damaging alternatives (e.g., recycling rather than landfill). Any other valid point. Oxford University Press This resource sheet may have been changed from the original.

12 B8.8 Trophic levels and biomass a mass of biological material in living organisms b Dry biomass shows amount of biological material at each level more accurately but necessitates killing and drying out organisms. Wet biomass values much easier to obtain as does not involve killing organisms, but is less useful as water content of living organisms varies constantly, making results less repeatable and reproducible. 2 a Award marks for accurate pyramid correctly labelled. 3 2 b Amount of material contained in biomass of organisms at each stage of a food chain less than it was at the previous stage. Not all of organism at one stage eaten by organism at next stage (only leaves of grass eaten by sheep, only blood of sheep eaten by ticks). Some materials taken in passed out and lost as waste products. Much of materials taken in used in cellular respiration to release energy for cell metabolism and some energy transferred to surroundings. Relatively small amount of material taken in converted to new biomass. Large percentage of biomass in grass cropped by sheep not converted to biomass in sheep and large percentage of biomass in sheep not converted into biomass in sheep ticks. 3 a 00 = 0.02 = 2% 3 b 00 = 0.05 = 5% Oxford University Press This resource sheet may have been changed from the original. 2

13 B8.9 Biomass transfers a Some of the biomass ingested by an animal cannot be used. Most herbivores cannot digest cellulose in plant material. Most carnivores cannot break down and digest hooves, claws, bones, and teeth. Indigestible materials are egested as faeces, meaning biomass is lost. b Biomass used in cellular respiration to provide energy for movement and to supply energy and raw materials needed for building new biomass. Active animals carry out lots of respiration as active, contracting muscles respire more. More of the biomass eaten is broken down and used for movement in active animals and more energy is transferred to surroundings as muscles warm up. 2 a flow chart should include: producers primary consumer secondary consumer tertiary 4 consumer decomposers 2 b Biomass lost by consumers in faeces cellulose cannot be digested by herbivores, animal parts such as hooves/claws/bones/teeth cannot be digested by carnivores. Biomass lost by producers and consumers in waste excess protein and water lost in urine, carbon dioxide and water lost in respiration. Biomass lost in consumers in maintaining a constant body temperature energy transferred to surroundings. Oxford University Press This resource sheet may have been changed from the original. 3

14 Question 3 Only about % of energy from Sun s light falling on Earth (incident energy) used by plants for photosynthesis to create biomass. Plant biomass eaten by animals cannot all be digested. Some is broken down and used in respiration to provide energy for living processes such as movement and regulating body temperature. Only small amount of biomass eaten by animals used for growth to produce new biomass. Answer Marks Guidance Oxford University Press This resource sheet may have been changed from the original. 4

15 B8.0 Factors affecting food security having enough food to feed a population 2 Any three reducing factors from: 3 Any other valid point. increasing birth rate, new pests and pathogens, changing diets in developed countries, environmental changes, cost of agricultural inputs, conflicts. Any three increasing factors from: maintaining or improving soil quality, efficient ways to produce food (e.g., selective breeding or GM technology), managing fish stocks, educating populations 3 3 Quinoa staple food in Bolivia. Production of quinoa in Bolivia has increased since 997. Quinoa has increased in popularity in other countries, leading to increased exports as farmers can charge more to foreign buyers than to local consumers and make more money. Local consumption of quinoa has fallen as exports have increased. Food security in Bolivia reduced as population increasingly dependent on imported pasta. 4 Accept any well-researched opinion and explanation. 6 Oxford University Press This resource sheet may have been changed from the original. 5

16 B8. Making food production efficient a so that animals do not have to use much biomass in cooling down, leaving more biomass for growth b Biomass lost through faeces, urea, and respiration for movement and regulation of body temperature. 2 Earth has limited surface area for plant growth. Biomass lost at each stage of food chain. Shorter food chains more efficient. If people all ate plants instead of feeding plants to animals and then eating animals, food chains would be shorter. Efficiency of food production would be greatly increased as plant biomass would be used to produce human biomass directly. 3 advantages: indoor work, animals grow faster so ready for market sooner, control of movement and temperature maximises conversion of food to biomass, weather conditions don t matter, fish farming conserves wild stocks; disadvantages: initial cost of buildings, cost of light and heating, higher feed bills, animals may be stressed (gain biomass more slowly), ethical concerns 6 Any other valid point. Oxford University Press This resource sheet may have been changed from the original. 6

17 B8.2 Sustainable food production a development of large commercial fleets capable of catching huge quantities, uncontrolled overfishing b control size of the holes in nets so only largest fish caught, ban fishing during breeding season, strict catch quotas c Points may include: people dependent on fishing for livelihood and wary of reduced income, difficult to obtain overall picture of global fish stocks, difficult to apply 3 Any other valid point. quotas across large oceans fished by multiple countries. 2 a 969 (accept between 967 and 969).8 million tonnes (accept.7 to.9 million tonnes) 2 b 0. million tonnes 2 c = , 2 d i 00 = 94%, 00 = 400% increase accept correct calculation based on answers given in parts a and b 2 d ii 00 = 480% increase 2 d iii 00 = 600% increase 2 e some fish species almost extinct, fish caught over quota discarded dead so cannot increase populations, quotas difficult to enforce internationally accept any answers based on appropriate readings from Figure 2 Any other valid point. Oxford University Press This resource sheet may have been changed from the original. 7

18 3 similarities: fermenter equivalent to enclosed shed or barn, fermenter temperature regulated and food supply maintained to give the optimum conditions, designed to achieve maximum growth over minimum time, cost of maintaining conditions outweighed by increased production; differences: fungus not an animal so controlled conditions cause no stress, no ethical issues, ph not monitored and maintained in farming, no free-range alternative in mycoprotein production. 6 Any other valid point. Oxford University Press This resource sheet may have been changed from the original. 8