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  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment Teacher notes See the ‘ Earth’s Atmosphere ’ chemistry presentation for more information on the atmosphere and air pollution.
  • Boardworks GCSE Science: Biology Human Impact on the Environment Teacher notes See the ‘ Climate Change ’ chemistry presentation for more information on greenhouse gases, the greenhouse effect and global warming.
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Photo Credit: NASA. Image of Venus
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment Photo credit:  © 2006 Jupiterimages Corporation
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment Photo credit: © 2006 Jupiterimages Corporation Image shows excess algal growth caused by eutrophication.
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment Photo credit: Marcel Hol
  • Boardworks GCSE Science: Biology Human Impact on the Environment Photo credit: Paco Navarro (www.ohestudio.com)
  • Boardworks GCSE Science: Biology Human Impact on the Environment Teacher notes See the ‘ Making Polymers ’ chemistry presentation for more information on disposing of plastics.
  • Boardworks GCSE Science: Biology Human Impact on the Environment Teacher notes See www.acrr.org for more information on recycling. Photo credit: Vicky S
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Boardworks GCSE Science: Biology Human Impact on the Environment
  • Transcript

    • 1. 1 of 37 © Boardworks Ltd 2006
    • 2. 2 of 37 © Boardworks Ltd 2006
    • 3. Human impact on the environmentHow does human activity affect the environment? 3 of 37 © Boardworks Ltd 2006
    • 4. Population growthThere are about 6.6 billion people in the world and over 95million babies are born per year – that is an average ofthree babies per second!Has the rate of population growth always been the same? 4 of 37 © Boardworks Ltd 2006
    • 5. Exponential growth 5 of 37 © Boardworks Ltd 2006
    • 6. Exponential growthThe human population is said to be growing exponentially.This means that the larger the population, the faster it grows.An increase in average life expectancy is largelyresponsible for the rapid increase in population. Why dopeople live longer than they did hundreds of years ago? better healthcare (hospitals, medicines, vaccines) more and better food cleaner water better sanitationThe biggest increase in population is in developing nations,rather than developed nations. Why do you think is the case? 6 of 37 © Boardworks Ltd 2006
    • 7. Predicting future growth rateComputer models can be used to make predictions aboutpopulation growth by using assumptions about birth rate.Most analysts assume that birth rates will fall within thenext 50 years. Why do you think this might happen? decreased fertility lack of resources disease warHow important do you think predictions about climatechange and unsustainable development are in the analysts’calculations? 7 of 37 © Boardworks Ltd 2006
    • 8. Future population growth 8 of 37 © Boardworks Ltd 2006
    • 9. 9 of 37 © Boardworks Ltd 2006
    • 10. Air pollutionHuman activity produces two main types of air pollutant: noxious gases – These include carbon dioxide (CO2), sulfur dioxide (SO2) and nitrogen oxides (NOx). particulates – These are tiny particles suspended in air (e.g. smoke) and which are usually produced by the combustion of fossil fuels.Air pollution has been a major problem since the IndustrialRevolution of the late 18th Century, and has been madeworse by humans’ reliance on burning fossil fuels for energy.Air pollution, global warming, acid rain, damage to the ozonelayer and smog. Each of these has serious implications forthe environment and human health. 10 of 37 © Boardworks Ltd 2006
    • 11. Global warming and greenhouse gasesOne of the greatest threats caused by air pollution is globalwarming. Global warming is caused by a build-up ofgreenhouses gases, which leads to an increase in theEarth’s temperature.A greenhouse gas is an atmosphericgas that absorbs infrared light.Key greenhouses gases include: carbon dioxide (CO2) methane (CH4) water vapour (H2O) nitrous oxide (N2O) 11 of 37 © Boardworks Ltd 2006
    • 12. The greenhouse effect 12 of 37 © Boardworks Ltd 2006
    • 13. The greenhouse effect 13 of 37 © Boardworks Ltd 2006
    • 14. How hot can the greenhouse effect get?The planet Venus is furtherfrom the Sun than Mercurybut has an higher averagetemperature. Its surface canreach up to 482°C, which ishot enough to melt lead!Venus’ atmosphere is mostlymade up of carbon dioxide,which traps so much of thesolar radiation that the planetbecomes extremely hot.The hostile climate conditionson Venus make it impossiblefor life to survive. 14 of 37 © Boardworks Ltd 2006
    • 15. Greenhouse gases 15 of 37 © Boardworks Ltd 2006
    • 16. What is global warming?The term “global warming” is oftenused in connection with climate change,but what does it mean?Global warming refers to the increasein the Earth’s temperature due to thegreenhouse effect, which can causechanges in climate.However, the term “global warming” is being used nowto refer to the warming predicted to occur as a result ofincreased emissions of greenhouse gases and otherhuman activities. This enhanced greenhouse effect maylead to significant climate change.Remember, global warming and climate change are notthe same thing and should not be used interchangeably. 16 of 37 © Boardworks Ltd 2006
    • 17. Why is carbon dioxide so important?Carbon dioxide is considered themost significant greenhouse gas.This is because carbon dioxide canremain in the environment over along time, from 50 to 200 years.Any process producing carbon dioxide today could affectthe climate for hundreds of years.Carbon is present in all living things and moves through theenvironment in a chain of reactions called the carbon cycle.Levels of carbon dioxide in the atmosphere have increasedsince the industrial revolution in the 19th century.How might human activities have contributed to this? 17 of 37 © Boardworks Ltd 2006
    • 18. Atmospheric carbon dioxide 18 of 37 © Boardworks Ltd 2006
    • 19. Carbon dioxide levelsCarbon dioxide is one of the most important greenhousegases because atmospheric concentrations have risendramatically over the past century. Why do you think this is?Burning fossil fuels, deforestation andflooding land for the construction ofhydroelectric dams have all contributedto rising levels of carbon dioxide. How many examples of burning fossil fuels can you think of? Are there any alternatives? 19 of 37 © Boardworks Ltd 2006
    • 20. What is the carbon sink?Before the industrial revolution, carbon dioxide levels wereusually kept in check by the carbon sink – forests andoceans that capture and store carbon. forests – All green plants absorb carbon dioxide as part of photosynthesis. The absorbed carbon is only released back into the atmosphere when the plant dies and rots, or is burned. oceans – Carbon dioxide dissolves in sea water, depending on the temperature and pressure. Tiny marine animals called phytoplankton extract carbon from the carbon dioxide to make their skeletons and shells. 20 of 37 © Boardworks Ltd 2006
    • 21. The carbon sink 21 of 37 © Boardworks Ltd 2006
    • 22. Acid rain 22 of 37 © Boardworks Ltd 2006
    • 23. What damages the ozone layer?The ozone layer is a protective part of the atmosphere thatabsorbs some of the Sun’s damaging ultraviolet (UV) rays.Damage to the ozone layer means that more UV raysreach Earth, increasing the risk of skin cancer.The ozone layer is damaged by chemicals calledchlorofluorocarbons (CFCs), which contain the elementscarbon, hydrogen, chlorine and fluorine.CFCs are used in fridges and freezers, aerosol sprays andpackaging materials such as polystyrene. The productionand use of CFCs is now banned in many countries and couldbe worldwide in a few years. 23 of 37 © Boardworks Ltd 2006
    • 24. What is smog?Smog is a mixture of air pollutants and particulates that issometimes found in the lower levels of the atmosphere. Ithas a distinctive brownish haze.Smog can reachdangerous levels in built-up areas, causing irritationto the eyes and lungs.A large part of smog isground-level ozone, ahighly toxic gas.Ozone is formed when nitrogen oxides and hydrocarbonsreact with oxygen, in a reaction catalyzed by sunlight. 24 of 37 © Boardworks Ltd 2006
    • 25. 25 of 37 © Boardworks Ltd 2006
    • 26. Water pollutionSewage, industrial waste, oil, pesticides and fertilizers allpollute water.Fertilizers and sewage can easily be washed into rivers,streams and lakes. The nutrients, phosphates and nitrates inthese substances cause eutrophication.Eutrophication is theaccumulation ofnutrients in water, whichcauses excessive algalgrowth. This leads to areduction in oxygenlevels and the death ofaquatic life. 26 of 37 © Boardworks Ltd 2006
    • 27. Eutrophication 27 of 37 © Boardworks Ltd 2006
    • 28. Eutrophication 28 of 37 © Boardworks Ltd 2006
    • 29. 29 of 37 © Boardworks Ltd 2006
    • 30. Land pollutionLand and soil can be polluted by two main types ofsubstance: solid waste – such as plastic, metal, paper and other man- made substances chemicals – such as herbicides and pesticides, crude oil and waste from industrial processes.Land pollution often leads towater pollution, as chemicals arewashed into rivers and lakes. 30 of 37 © Boardworks Ltd 2006
    • 31. How much waste?Every year, billions of tonnes of paper, plastics, syntheticmaterials, metal and wood are thrown away.On average, each UKhousehold producesover 1 tonne of rubbisheach year.How could you estimatethe amount of rubbishyou throw away eachyear? 31 of 37 © Boardworks Ltd 2006
    • 32. What are the options?What methods are there for disposing of waste materials? Landfill is the cheapest solution, but sites quickly become full and the waste contaminates the surrounding air, soil and water. Incinerating waste reduces volume, but often produces toxic chemicals. Recycling materials allows them to be useful again, and reduces the need to use more raw materials. Composting uses natural biological processes to decompose organic materials, but cannot be used to dispose of non-biodegradable waste. 32 of 37 © Boardworks Ltd 2006
    • 33. What is the best solution?The best way to deal with waste is to produce less of it!It takes 100 kg of resources to make 10 kg of shopping,and most of that ends up in the bin.If products wereredesigned to bebiodegradable or easierto recycle, the amountof waste and disposalcosts would besignificantly reduced.How could you reduce the amount of waste you produce? 33 of 37 © Boardworks Ltd 2006
    • 34. Recycling rates 34 of 37 © Boardworks Ltd 2006
    • 35. 35 of 37 © Boardworks Ltd 2006
    • 36. Glossary (1/2)biodiversity – The number of different species within a specific habitat.chlorofluorocarbon – A chemical that damages the ozone layer.eutrophication – Over-enrichment of water with nutrients, causing excessive algal growth and reduced oxygen levels.global warming – The rise in the Earth’s temperature caused by an increase in greenhouse gases from human activity.greenhouse gas – A gas that traps the Sun’s infrared radiation in the Earth’s atmosphere. 36 of 37 © Boardworks Ltd 2006
    • 37. Glossary (2/2)indicator species – An organism whose presence or absence provides information on environmental conditions.ozone – A gas that is toxic at ground level but which forms a protective layer higher in the Earth’s atmosphere.particulate – A type of pollution consisting of tiny particles, such as smoke.pollutant – A substance that contaminates air, water or land.smog – A hazardous type of air pollution containing ozone and particulates. 37 of 37 © Boardworks Ltd 2006
    • 38. Anagrams 38 of 37 © Boardworks Ltd 2006
    • 39. Multiple-choice quiz 39 of 37 © Boardworks Ltd 2006