1 THE EFFECTS OF THE POPULATION EXPLOSION p. 264

Objectives  Students should learn:  that rapid growth in the human population means that more waste is produced  that humans reduce the amount of land available for other animals and plants by building, farming, quarrying and dumping waste.

Outcomes Most students should be able to:  explain how human population growth has occurred  explain why raw materials are rapidly being used up and more waste is being produced  describe the effects of population growth on land and resources. Some students should also be able to:  analyse and interpret scientific data concerning human population growth and environmental issues.

Specification  Rapid growth in the human population and an increase in the standard of living means that increasingly more waste is produced. Unless waste is properly handled, more pollution will be caused. [B3.4.1 a)]  Waste may pollute:  – water, with sewage, fertiliser or toxic chemicals  – air, with smoke and gases such as sulfur dioxide, which contributes to acid rain  – land, with toxic chemicals such as pesticides and herbicides, which may be washed from the land into waterways. [B3.4.1 b)]  Humans reduce the amount of land available for other animals and plants by building, quarrying, farming and dumping waste. [B3.4.1 c)]

Workbook  P

H OW B IG IS THE H UMAN P OPULATION ? March ,300,000,000 W HY ? Advancements made in medicine Developments made to the farming industry Heightened rate of natural increase

H OW F AST IS THE P OPULATION G ROWING ? Has doubled in 40 years, ( billion  billion) increase of 1.14% per year The average population increase is currently estimated at 80 million per year Estimated to reach 8 billion by 2024

The changing population

H OW DO H UMANS AFFECT L AND ?  Housing  Shops  Roads  Industrial uses  Farming  Quarrying Destruction of habitats Disruption of eco-systems Pesticides and herbicides may remain in soil for years Potentially impact the food chains within an eco-system Pollution may accumulate to toxic levels The disposal of waste, (often containing toxic chemicals), also reduces the amount of land and resources available to other animals/plants. The removal of this waste can lead to air and water pollution. Draining Earth’s finite resources (e.g. metal ores, fossil fuels)

H OW DO HUMANS AFFECT WATER ? Through the development of industry and rapid population growth, vast quantities of waste are being produced. This may lead to water pollution- sewage may pollute water supplies if not dealt with correctly, potentially resulting in disease outbreaks. Through the discharge of harmful substances into bodies of water, food chains within the local eco-system may be severely affected. What substances commonly pollute water?  Excess nutrients from sewage/fertilisers - may contain high mineral levels or harmful pathogens  Toxic chemicals from industry - may accumulate in food chains to toxic levels The process of eutrophication can have major consequences on the eco-system.

H OW DO H UMANS AFFECT AIR ? The increased use of fossil fuels, (as a direct result of rapid population growth and a greater energy demand), has resulted in the increased production of pollutant gases. The combustion of fossil fuels is the most common source of air pollution. Air PollutantSourceEffect SmokeIncomplete combustion of fossil fuelsDeposition of soot on buildings/trees Permeates air- breathing problems Sulfur dioxideSulfur impurities in fossil fuelsAcid rain- Damages buildings Disrupting aquatic eco-systems Carbon dioxideHydrocarbon fuels Greenhouse gas  global warming MethaneAnaerobic decomposition of landfill waste Rice fields Cows Greenhouse gas  global warming

T HE F UTURE ? By 2050, the human population is projected to reach 9.4 billion The rate of growth is expected to decrease, (to approximately 0.5%) Resources will continue to be used rapidly The continued disruption to the ecology of the planet will have massive consequences Research is being carried out into alternative fuels/resources in order to supply our growing energy demand.

Computer models can be used to make predictions about population growth by using assumptions about birth rate. Predicting future growth rate Most analysts assume that birth rates will fall within the next 50 years. Why do you think this might happen? How important do you think predictions about climate change and unsustainable development are in the analysts’ calculations? decreased fertility lack of resources disease war

The human population is currently. This has occurred due to advancements made in medicine and developments made to the farming industry. As a result of various reasons, including building, farming and quarrying, humans are continuing to disrupt eco-systems by polluting and damaging the land. Excess nutrients and toxic chemicals from industry may wash from the land into waterways, contributing to the process of 7.3 billion medicine farming quarrying nutrientstoxic eutrophication. farming toxic quarrying eutrophication nutrients medicine 7.3 billion

Play odd man out with the class give a reason in each case 1. Oil Coal Recycling 2. Houses Rivers Trees 3. Toxic chemicals Nutrients Eutrophication 4. Wind Petrol Sun 5. Water Rubbish Sewage 6. Hills Rivers Lakes 7. Noise Air Cars

Biology B3 4.1 The effects of the population explosion Answers to in-text questions a 6.8 billion. b By building houses and roads, by farming, by quarrying and by dumping waste. c i Water: excess nutrients from sewage and fertilisers from farms and by toxic chemicals from industry. ii Air: Carbon dioxide from the burning of fossil fuels, smoke and poisonous gases such as sulfur dioxide. iii Land: toxic chemicals from farming such as pesticides and herbicides, industrial waste, such as heavy metals. Summary answers 1 population, two hundred, farming, food, treat, diseases, predators, increase 2 a Any sensible suggestions, e.g. use of electricity for lighting, heating, TV etc.; use of fossil fuels for transport (cars, planes etc.); plastics. b Any three suitable suggestions, such as fossil fuels, wood, land, metals, etc. 3 Look for clarity of explanation without copying the Student Book. Points covered should include:  Growing human population increases the amount of waste: bodily waste and the rubbish from packaging, uneaten food and disposable goods.  The dumping of waste produced by the ever-expanding human population makes large areas of land unavailable for other life.  Driving cars etc. leads to gases from exhausts.  Farming leads to the use of pesticides and fertilizer sprays that cause pollution.