Environmental Management Textbook PDF - Cambridge IGCSE & O Level

Gary Skinner, Ken Crafer, Melissa Turner, Ann Skinner and John Stacey Cambridge IGCSE® and O Level Environmental Management Coursebook University Printing House, Cambridge CB2 8BS, United Kingdom One Liberty Plaza, 20th Floor, New York, NY 10006, USA...

Gary Skinner, Ken Crafer, Melissa Turner, Ann Skinner and John Stacey Cambridge IGCSE® and O Level Environmental Management Coursebook University Printing House, Cambridge CB2 8BS, United Kingdom One Liberty Plaza, 20th Floor, New York, NY 10006, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia 4843 / 24, 2nd Floor, Ansari Road, Daryaganj, Delhi – 110002, India 79 Anson Road, #06–04 / 06, Singapore 079906 Cambridge University Press is part of the University of Cambridge. It furthers the University’s mission by disseminating knowledge in the pursuit of education, learning and research at the highest international levels of excellence. www.cambridge.org Information on this title: www.cambridge.org / 9781316634851 (paperback) © Cambridge University Press 2017 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2017 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 Printed in Malaysia, by Vivar Printing A catalogue record for this publication is available from the British Library isbn 978-1-316-63485-1 Paperback isbn 978-1-316-63491-2 Cambridge Elevate enhanced edition (2 years) isbn 978-1-316-64602-1 Paperback + Cambridge Elevate enhanced edition (2 years) Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party internet websites referred to in this publication, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. 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In examinations, the way marks are awarded may be different.  notice to teachers in the uk It is illegal to reproduce any part of this work in material form (including photocopying and electronic storage) except under the following circumstances: (i) where you are abiding by a licence granted to your school or institution by the Copyright Licensing Agency; (ii) where no such licence exists, or where you wish to exceed the terms of a licence, and you have gained the written permission of Cambridge University Press; (iii) where you are allowed to reproduce without permission under the provisions of Chapter 3 of the Copyright, Designs and Patents Act 1988, which covers, for example, the reproduction of short passages within certain types of educational anthology and reproduction for the purposes of setting examination questions. Contents How to use this book iv 5.3 Exploitation of the oceans: impact on fisheries 121 Introductionvi 5.4  trategies for managing the harvesting of marine S Key skills in Environmental Management viii species123 6 Managing natural hazards 132 1 Rocks and minerals and their exploitation 1 6.1 What is a natural hazard? 133 1.1 Formation of rocks 2 6.2  hat causes earthquakes and volcanic W 1.2 Extraction of rocks and minerals from the Earth 6 eruptions?134 1.3 Impact of rock and mineral extraction12 6.3 What causes tropical cyclones? 141 1.4 M  anaging the impact of rock and mineral 6.4 What causes flooding? 143 extraction15 6.5 What causes droughts? 146 1.5 Sustainable use of rocks and minerals 16 6.6 Impacts of natural hazards 146 2 Energy and the environment 25 6.7 Strategies to manage the impact of natural 2.1 Fossil fuels 26 hazards148 2.2 Energy resources 27 6.8 Opportunities presented by natural hazards 150 2.3 The demand for energy 33 7 The atmosphere and human activities 156 2.4 C  onservation and management of energy 7.1 T  he structure and composition of the resources35 atmosphere157 2.5 Impact of oil pollution 42 7.2 Atmospheric pollution and its causes 160 iii 2.6 Management of oil pollution 44 7.3 The impact of atmospheric pollution 162 3 Agriculture and the environment 50 7.4 Managing atmospheric pollution 164 3.1 The soil 51 8 Human population 173 3.2 Soils for plant growth 54 8.1 Changes in population size 174 3.3 Agriculture57 8.2 Human population distribution and density 179 3.4 Increasing agricultural yields 59 8.3 Population structure 182 3.5  he impact of agriculture on people T 8.4 Managing human populations 183 and the environment 70 3.6 Causes and impacts of soil erosion75 9 Natural ecosystems and human activity 188 3.7 Methods to reduce soil erosion 77 9.1 The ecosystem 189 3.8  n integrated approach for sustainable A 9.2 Estimating biodiversity in ecosystems 197 agriculture81 9.3 The causes and impacts of habitat loss 200 4 Water and its management 89 9.4 The causes and impacts of deforestation 202 9.5 The need for sustainable management 4.1 The distribution of water on Earth90 of forests 204 4.2 The water cycle 91 9.6 Strategies for conserving the biodiversity 4.3 Why humans need water 92 and genetic resources of natural ecosystems 206 4.4 The main sources of fresh water for human use 92 4.5  vailability of safe drinking water around the A world94 Answers to Self-assessment questions 219 4.6 Multipurpose dam projects 95 Answers to End-of-chapter questions 228 4.7 Water-related diseases 96 Answers to Case study questions 235 4.8  ources, impact and management of water S Answers to Extended case study questions 239 pollution100 Answers to Practical activity questions 245 5 Oceans and fisheries 112 Glossary246 5.1 The resource potential of the oceans 113 Acknowledgements253 5.2 World fisheries 116 Index254  uickly and hat was are formed lutions Cambridge IGCSE and O Level Environmental Management How to use this book minerals. solution to a surface rystal Greenfield s minerals. Th Learning outcomes – These statements set the scene of Opening discussion – An engaging discussion to bring For some m s can form each chapter, help with navigation through the book and each chapter topic to life, encouraging you to read around 1 : 100. New ccurs when give a reminder of what’s important about each topic. the topic and sparking discussion in class. Figure 1.3 A piece of basalt. rate may be face of the 1 Chapter 1 Cambridge IGCSE and O Level Environmental Management Brownfield thout Sedimentary rocks and their exploitation Rocks and minerals They usuall Sedimentary rocks are formed by the weathering of The third rock from the Sun with oil. In 1956, the originator of the peak mineral idea, Even low-gr ools more Learning outcomes The Earth is a rocky planet, compared with, for example M. K. Hubbert, predicted that the peak oil date for the existing rocks at the Earth’s surface, the accumulation Jupiter, which is a gas giant. This means that the Earth USA would be 1970. This did not happen, and in fact the past may ha Many of By the end of this chapter, you will be able to: is made from rocks and metal ores. The Earth weighs production of oil in the USA is still rising today. However, it is true that the resources of all these commodities, such anddescribe, fossilisation of living material, or the rocksprecipitation of 5 973 600 000 000 000 000 000 000 kg (5.97 × 1026 kg) and has as coal, oil and phosphorus (current estimated peak date for profit. e used for a with examples, the characteristics of igneous, sedimentary and metamorphic explain the formation of igneous, sedimentary and metamorphic rocks a density of 5.2 g cm–3, which makes it the densest planet in 2030), copper (current estimated peak date 2040) and dissolved materials out of solution in water. Weathering the solar system. This is mainly because the core consists uranium (current estimated peak date 2030s), are finite. explain the rock cycle describe surface and subsurface mining of iron surrounded by a mantle of rock. However, it is only the very outside part of the Earth, above the mantle, It is therefore important that we limit the use of these A The probab processes release describe the reasons small for extracting rocks mineral particles that accumulate and minerals that humans can use. The material that makes up this resources, and reuse and recycle them whenever we can. be calculate rals describe the impact of rock and mineral extraction on the environment and human populations to form discuss sediment. Over time, methods of landscape restoration after rock and minerallayers extraction of sediment build up to region is what we call rocks and minerals. Although this represents a vast amount of material, the quantity of it, like by open-pit everything else, is limited. What is more, extraction and essure explain the terms sustainable resource and sustainable development form sedimentary rock. discuss how rocks and minerals can be used sustainably. use can cause environmental and other problems. We are difficulties t miners’ elevators 3 in danger of using up the available sources of many rocks, coal elevators the most well known of which is probably coal. The sediments include different-sized mineral particles. Peak mineral is a concept that provides a date after which there will only be less extraction of a mineral. Peak coal, for which leads t The smallest particles are clays, followed by silts and then example, is the date at which it is calculated that the most coal is being extracted, after which it will decline. Because Deeper dep Key terms sands. andparticles These definitions - Clear andinstraightforward are important the formation of we do not know exactly how much coal exists, estimates B This is more of peak coal vary. Some say it is 200 years away, others explanations soils (see of the Section most 3.1). important terms Larger particles are provided for Managementof gravels and small 2 say it could be soon, maybe 2020. This unpredictability because of future unknowns is illustrated by the situation Figure 1.0 A giant bucket wheel excavator in use in an open-pit mine. Cambridge IGCSE and O Level Environmental per tonne w each topic. boulders can also be found in sediments. 1.1 Formation of rocks Igneous rocks deposits of When molten rock from the crust and upper mantle cools, The planet Earth was formed about 4.5 billion years ago. igneous rocks are formed. The molten rock is called this way. case study The force of gravity pulled the heavier elements together magma when it is still below the surface and lava when it The Keyone-child teRMS policy in China Self-assessment C questions – Check your knowledge first, forming the core. The lighter elements then formed reaches the surface. iv the Earth’s crust about 3–4 billion years ago. The mantle Magma is found in the outer mantle; it is hot, liquid rock The quality and understanding, and track that your progress by it.answering developed as a layer between the dense core and the light By the early 1970s the population of China had 1 600 000 000 is under pressure from the rocks above predictedcrust. This structure still exists today (Figure 1.1). When it Rock: a combination of one or more minerals reached almost 1 billion. The response of the actual factor in de questions Figure 1.14 A drift mine with a horizontal entrance,provided throughout each chapter. Answers are 1 400 000 000 crust continental crust government was quite simple. Couples who had 10 called 0–100 km Mineral: a naturally occurring inorganic substance with a only one child were rewarded with money and 1 200 000 000 mantle yield more Population oceanic crust other benefits. Those who had more children 1 000 000 000 at the back of the book. an adit. B Sloping tunnel. outer core low-grade o 2900 km specific chemical composition than this received no such rewards and, in many 800 000 000 cases, were fined. It is estimated that about inner core 5100 km Igneous rock: rock made during a volcanic 600 000process 300 million fewer Chinese are alive today (2016) 000 than there would have been if the policy had not 400 000 000 6370 km The size of d Magma: molten rock below the surface of the1950 been implemented. Predictions suggest that the Earth1970 Self-aSSeSSment queStionS mantle Small depo 1990 2010 2030 2050 population of China will begin to fall in about Year 2030.Solution: formed when a solid is dissolved inThe Figure 8.14 a actual liquidand predicted growth of the be worth m It can be concluded that the policy has been population of China from 1955 until 2050. 1.3 What factors need to be considered before Precipitates: when a substance comes out of solution successful, but there have been many problems. In Figure 1.1 The structure of the Earth. low-value o rural areas, people rely on young family members Questions starting up a new mine? Ion: an atom in which the number of positively to work in the fields. This meant that the one-child charged protons known rese 1 Use the information in Figure 8.14 to: policy had to be relaxed in such areas. As a result is not equal to the number of negatively charged a calculateelectrons 1.4 Suggest reasons why developing surface mines the plan to limit the population to 1.2 billion was the predicted increase in the population because tec not achieved. There will also be problems in the Sedimentary rock: a rock formed from bmaterial derived from of China from 2020 until it starts to fall is easier than developing mines underground. future, when one person may have both parents and calculate what the population of China would have been in 2015 if the one-child policy had because of the weathering of other rocks or the accumulation of dead four grandparents to look after alone. In the past not been implemented. most older people lived with their family, but it is 184 plants and animals likely to become more common for older people to 2 In late 2015 it was announced that the one-child It is possibl live in some type of nursing home. policy was to be abolished and people would be The natural preference for boys in rural allowed to have two children. Suggest three reasons many facto communities has meant that many girls were why you think this was done. Factors affecting the viability of extraction factors are Practical abandoned activity – Opportunities and have been raised as orphans. for 3 developing Suggest why the one-child policy may have been Men now outnumber women in China by many practical millions. skills are provided throughoutinthe more successful in China than it would have been other book. countries. of minerals extraction. Once a mineral deposit has been located, a mining life, then ot practical activity 8.1 company has to decide whether it should mine the deposit important i Seven billion and counting or not. Mining companies need to consider a range of On a large sheet of paper (at least A3), draw the world Mines that a The world population is assumed to have reached 7 billion issues when planning to open a mine, including: population size from 1500 to the present day. You can get help with this on the website. likely to pre in October 2011. Danica May Camacho of the Philippines was designated as the 7 billionth human. Mark your birth number on the world population time line. the costs of exploration and extraction Transportin Materials Choose five historical world events and five events Access to the internet from your country’s history. Mark these events on your geology be difficult a poster. A3 or larger sheet of paper Marker pens Question a deposit b 1 Estimate the world’s population at the time your chosen climate links to the Method historical events happened. For example, when the If you go to the BBC website (www.cambridge.org/links/ scspenv4002) you can find out what number in the Second World War ended, the world population was accessibility port for exp about 2 300 000 000. world’s population you were when you were born. These trans the environmental impact so there wil supply and demand. transportin  How to use this book Case study – A variety of examples of real world scenarios End-of-chapter questions – Use the questions at are included in every chapter to illustrate relevant aspects the end of each chapter to check your knowledge of the syllabus, with questions to develop your higher order and understanding of the whole topic and to practise thinking skills. Answers are provided at the back of the book. Cambridge IGCSE and O Level Environmental Management answering questions in a similar style to those you might encounter in your exams. Answers are provided at the back of the book. Chapter 3: Agriculture and the environment case study Acid rain in China Heilongjiang End-of-chapter questions Beijing Jilin Xinjiang Ningxia Liaoning 1 a Name the four components of soil. [4 marks] Inner Mongolia Tianjin b How would a drought affect the balance of these four components? [1 mark] Hebei Shandong Qinghai Shanxi Shanghai 2 How might changing the pH of the soil affect the growth of a crop? [1 mark] Gansu Shaanxi Henan Jiangsu Tibet Sichuan Anhui 3 Give three ways the ‘Green Revolution’ has helped feed a growing Hubei Zhejiang world population. [3 marks] Cambridge IGCSE and O Level EnvironmentalChongqing Management Hunan Jiangxi Guizhou Fujian 4 Explain how crop rotation can help increase the yield of a crop. [2 marks] key Yunnan Taiwan Guangxi Guangdong < pH 4.5 5 Describe three ways farmers can improve the efficiency of their water use. [3 marks] pH 4.5–5.0 Macau Hong Kong quality for irrigation (low in dissolved salts pH 5.0–5.6 and levels of challenges Hainan the world currently faces. To rise to this 6 Describe the impact of applying too much fertiliser to a crop. [2 marks] > pH 5.6 pollution) but does not have to be as clean as required for challenge, environmentalists need to understand and 7 Intercropping is identified as a useful way of helping prevent soil erosion in potable 166 (drinking) water and water supplied to livestock. manage a number of competing factors. Figure 7.5 The distribution of acid rain in China. certain soil conditions. In addition to the prevention of erosion, what other Sustainable agriculture uses alternative water supplies, The need to understand the nature and composition of benefits might this technique have? [3 marks] reserving water Chinafrom bore holes is experiencing rapidand other clean industrialisation. In sources 2011 soils: how the individual components have an impact for other uses. Forgovernment China’s example,published the collection of water a report that claimedfrom on how the soil reacts to changing circumstances. the roofs of that 258 Chinese buildings cities for is ideal wereirrigation. suffering from the is This effects knownof acid rain. The acid rain falls in the south and east of the as rainwater harvesting: collecting Why soil is important for plant growth: the need country, where the majority of therainwater from population, industry buildings andandhard-standing power stations areareaslocatedmeans it can (Figure 7.5). be China In 2014 stored for sufficient nutrients and how to manage the was the world’s in tanks or reservoirs largest until energy consumer, needed. The water accounting is thenfor soil to maximise the nutrient availability (and the 23% of all global energy consumption, and the dominant consequences of getting it wrong). pumped through an irrigation system from the fuel is coal, providing 66% of the country’s energy storage 85 container toconsumption. where it isWhen needed, when the coal it isinneeded. is burnt factories and How to manage soils with different characteristics to power stations, it releases sulfur dioxide and nitrogen In systems where a large oxide, which formamount acid rain.of water iscar Expanding being used,is ownership maximise their performance. the irrigationalso run-off leadingcan beemissions to high collected and gases. of these returned to The role of different types of agricultural systems: how the storage The pointeffects for ofre-use acid rain in China later. Thisare is anumerous. Lakes riskier method to address the different aims of different farmers. and rivers have become more acidic, killing fish, crop because salts may be leached out into the water and build yields are lower and commercial timber is being lost as up over time. Siltdie. can also bedamage carried in the run-off Ways in which yields can be improved and how the trees Structural to buildings is being and caused potentially block the irrigation by chemical weathering.system. The 71 m high and 28 m wide choice of different practices has an impact on the local Leshan Giant Buddha, which has stood for more than ecosystem and local people. 1000 years, has been badly affected (Figure 7.6). Key term The impact different practices have on soil erosion and China first attempted to reduce sulfur dioxide emissions in 2007, before the 2008 Beijing Olympics. In 2011, as Rainwater harvesting: the collection of rainwater, for what can be done to reduce it. part of the government’s Five-Year Plan, ambitious example from theforroofs targets of buildings, emission and reductions storage were in a tank or set. Several Figure 7.6 The Leshan Giant Buddha is starting How agriculture can produce the yields needed in a way to show the effects of acid rain. Cambridge IGCSE and O Level Environmental Management v reservoir for later use that is sustainable for the planet. 84 These are issues as much for the future as they are for extended case study today, because the challenges will not diminish. Other Towards a sustainable future? Controlling pests naturally: a flawed decision questions will come to the fore, such as the role of genetic Summary As a major employer and the largest land user of any – A brief industry in the world, agriculture summary has a major part to play is included at the end of modification and its potential to feed the hungry of the world, or whether global food problems can be solved by in the maintenance of a healthy and viable ecosystem. each chapter, The pressures on agriculture providing a clear reminder of the key themes to supply an increasing dictating what people are allowed to eat, using land for a larger quantity of crops rather than the luxuries of fine population but in a sustainable way is one the biggest discussed. foods and flowers that are available now. Summary After completing this chapter, you should know: the components of soil techniques used to increase agricultural yield where the soil components originate methods of controlling pests, diseases and weeds how to evaluate the proportions of these components the techniques of selective breeding and genetic the availability of nutrients and the impact of modification deficiencies methods for controlling the growing environment the relative merits of different soil types the impacts of poor agricultural management different types of agriculture different approaches to maintaining soil fertility. 86 Figure 3.22 The cane toad: introduced into Australia with a huge environmental impact. Extended case study – Longer case studies related to Sugar cane plants were introduced into Australia as the country became populated by Europeans. Records show that there were plantations in the Brisbane area as early as 1862. Plantations were densely planted, more complex real world settings provide opportunities tended to be grown as monocultures (only the one crop grown in an area) and today are highly mechanised. As the numbers of sugar cane plantations grew, so did the incidence of pests. Two native beetle species to practise higher order thinking skills and prepare for this cause major problems: the adults eat the leaves of the crop and their larvae eat the roots. These beetles have proved to be difficult to control because the adults have a tough skin that repels pesticides and the larvae are buried in the soil so are not easy to spray. When pesticides are used, not only are they not very element of your examinations. Answers are provided at the effective on the pests but they also kill many other insects and upset the natural ecosystem. Australian scientists looked at other areas of the world and read reports of increased yields in plantations in Hawaii, back of the book. the natural location of cane toads. Cane toads are relatively large in size and eat a wide range of different insects (Figure 3.22). A small number of cane toads were imported into Australia in the 1930s, bred successfully and released into the local plantations. Unfortunately, it was then discovered that the cane toad was not particularly effective at controlling the beetles on the Australian sugar cane, but preferred to eat other insects and animals in the area. It has been estimated that there are now over 200 million cane toads in Australia. They have bred rapidly because: they outcompete native animals for food they outcompete native animals for habitat space  Introduction Managing the environment might be the most important they are sciences that deal with interactions. You are a thing humanity has to do over the next century and part of the biosphere and each time you take a breath, beyond. But what is the environment and how can we you affect the atmosphere by adding carbon dioxide and manage it? In its broadest sense, the environment is water vapour and removing oxygen. Every time you eat, everything around us. Your environment includes the for example vegetables, you are taking in minerals that room you are sitting in, the air in that room, the people in have passed round and round a mineral cycle for millions the room next door, the aeroplane flying overhead and of years. This is at the heart of the difficulty of managing the atmosphere it is flying through, among many other the environment: anything and everything we do, either things. But how do we go about managing all of this? It is by design or by accident, may affect any aspect of the clear that we need to break things down so that the tasks environment. This is known as the law of unintended become manageable. That is what the syllabus and this consequences. book attempt to do. Food webs provide a good example of this law. In The environment can be split into four major categories: the complex interactions between species, feeding the lithosphere, hydrosphere, atmosphere and biosphere. relationships make it almost impossible to predict what Chapter 1 deals with the lithosphere: the rocks that make will happen if just one of species increases or decreases up our planet Earth, on which all life is found. Chapters 4 in number. Take Barro Colorado Island, formed when the and 5 deal with the hydrosphere: the ceaseless cycle of Panama Canal was constructed in the early twentieth water and what we do with it in its various forms. Chapter 7 century. Some decades after this area of tropical jungle vi looks at the atmosphere: the air around us, which contains was isolated from its surroundings, it was observed that vital oxygen and carbon dioxide and is the place where many species had been lost. These included birds such weather occurs. Chapters 8 and 9 look at the living world, as the curassow, the wood quail and the ground cuckoo. or biosphere: the people and all the animals, plants and The reason for this loss is thought to have been a medium- other organisms with which we share the Earth. Weaving sized racoon, called a coati, becoming abundant. through all of this is the use we make of energy, without (Figure 0.1) which nothing much of what we regard as our modern world could occur. Chapter 2 considers how we acquire the energy we need and the problems we create in using it. The environment is not necessarily well-meaning, although this might seem difficult to believe on a warm sunny day with the birds singing and soft wind blowing. Chapter 6 looks at the natural hazards that human and other life is constantly exposed to, from high winds and heavy rain that might cause problems for a few weeks, to the effects of earthquakes and volcanoes, which are the result of the incredibly slow movement of the tectonic plates on which we live. Finally, Chapter 3 covers that most vital of human activities: Figure 0.1 A coati family looking for food. farming. Recent studies have shown that nearly half of the Earth’s land area is used to produce food, and this is Coatis eat the eggs and young of birds like the curassow, almost certain to increase over the next few decades. wood quail and ground cuckoo. But why was there a big increase in coatis? In their jungle habitat, coatis are preyed However, having said all this, it is important to realise upon by jaguars and pumas (Figure 0.2); the new island, that every aspect of the environment affects every other. with an area of under 15 km2, was simply too small to This is the nature of environmental science and ecology; support these large cats.  Introduction Figure 0.3 Two great curassows. Figure 0.2 A female puma. that the numbers began to soar. By 1869 hunters were killing 2 million rabbits every year with no effect on the The cats would have died out in this isolated habitat and population. The huge numbers of rabbits in Australia have the coatis would escape being eaten. This would not have caused massive species loss and even geological changes, been predicted at the time: an unintended consequence of such as extensive gully erosion. the construction of the Panama Canal was the extinction of the curassow in a 15 km2 patch of tropical jungle, now The story of the cane toad, again from Australia (see an island (Figure 0.3). Chapter 3’s Extended case study), is another example of the important principle of unintended consequences in An even more dramatic example comes from the story vii environmental management. of rabbits in Australia. This European mammal was introduced into Australia in 1788 on the so-called First We all have an environment around us and we are all part Fleet (the first fleet of ships that left Great Britain to found of everybody else’s environment. This simple fact makes a penal colony in Australia). However, it was not until the managing the environment one of the most important deliberate release of just 24 individuals in October 1859 challenges for humans in the future.  Key skills in Environmental Management When thinking about an investigation in environmental (one variable has an effect on the other). The results are management you need to find out about a problem and not due to chance and they are significant in terms of how it is affecting the environment. An investigation has a supporting the aim being investigated. sequence of stages: A hypothesis can be accepted or rejected by testing. This is 1 planning the investigation achieved through data collection and analysis. 2 identifying limitations of the methods that were used A good hypothesis should: and suggesting possible improvements be a statement not a question 3 presenting reasoned explanations for phenomena, patterns and relationships that you have observed in be a prediction with cause and effect your data state the independent and dependent variables being 4 making reasoned judgements and reaching conclusions tested based on qualitative and quantitative information. be short in length. All these stages involve certain skills and techniques, all of which are explained below and in the following chapters. An example of a good hypothesis is ‘There will be a decrease in soil pH with increasing distance from a site of coal mining waste’. Planning investigations Planning an investigation involves formulating an aim and Key terms viii one or more hypotheses. An aim identifies the purpose Aim: identifies the purpose of your investigation of your investigation and you should have a suitable aim Hypothesis: a statement on the topic that you are investigating in mind when planning. ‘To investigate the effects of coal Independent variable: the variable that is deliberately mining waste on soil pH’ is an example of an aim. From the changed in an experiment aim, the hypothesis or hypotheses arise. Dependent variable: the variable that is measured in an A hypothesis is a statement on the topic that you are experiment investigating. It is a testable prediction that proposes a Null hypothesis: a hypothesis stating that there is no relationship between two variables: relationship between the two variables being investigated Alternative hypothesis: a hypothesis stating that there is a the independent variable, which is not changed by relationship between the two variables being investigated other variables you are measuring e.g. the age of a person the dependent variable, which is what you are measuring. Collecting data When planning an investigation, you need to plan how to In research, the hypothesis is written in two forms: the collect your data. There are two types of data: qualitative null hypothesis and the alternative hypothesis (called and quantitative. the experimental hypothesis when the method of investigation is an experiment). Qualitative data is non-numerical, descriptive data. The null hypothesis states that there is no relationship Quantitative data can be either discrete or continuous: between the two variables being investigated (one variable discrete data: numerical data that have a finite number does not affect the other). Results are due to chance and of possible values and can only take whole numbers, are not significant in terms of supporting the aim being e.g. the number of trees or 1, 2, 3, 4 investigated. continuous data: numerical data that have infinite The alternative hypothesis states that there is a possibilities and can take any value, e.g. temperature, relationship between the two variables being investigated time, speed or 1.5, 1.51, 1.512.  Key skills in Environmental Management Both qualitative and quantitative data can be either Once you have decided on the type of sampling to use, you primary or secondary: then have to decide on a suitable sampling method. There are three types of sampling methods. Primary data is data collected by you or a group doing the investigation. random sampling: sample points are selected using random numbers to avoid bias. Tables of random Secondary data is data that has already been numbers can be used or generated by calculators collected by people unconnected with the (see Chapter 9). investigation but that are relevant and useful. Examples include data from the internet, newspapers, systematic sampling: sample points are selected books or past investigations. using a regular pattern or order, e.g. conducting a questionnaire on every tenth person or surveying Sampling vegetation cover every 5 metres. It is often unnecessary and sometimes impossible stratified sampling: when a population is divided up to carry out your investigation on the whole of the into groups, e.g. different ages or gender, taking a target population as it would be too expensive or time stratified sample ensures that each group is asked in consuming. For example, it would be impossible to ask the correct proportion. everyone in a large town for their views on the effects of air pollution or to count all the plants in a big field. For this Key term reason a sample must be taken. Bias: encouraging one outcome over another A sample should be representative of the target population. If it is, then a larger sample size tends to yield more reliable results. The target population is the subset of people or Figure 0.5 summarises the different types of sampling organisms to which the conclusions of the study can be methods. applied. For example, if only women were questioned about ix random systematic stratified their views on air pollution the conclusions could only be applied to women, which would be the target population. point A Before deciding on the sampling method you need to think B about how you are going to take the sample. This could be by: line point sampling: data collection is done at an exact point, e.g. a pedestrian count line sampling: data collection is done along a line (Figure 0.4) or transect, e.g. changes in plant height quadrat area or quadrat sampling: data is collected within quadrants, e.g. vegetation cover surveys. Figure 0.5 Different types of sampling methods. For example, imagine you wanted to give a questionnaire to a sample of 50 people from a farming area. The area has three villages. How many people should be given a questionnaire from each village? Village 1 Village 2 Village 3 356 people 233 people 426 people Table 0.1 Population of the three villages. a The total number of people is 356 + 233 + 426 = 1015 Figure 0.4 Students carrying out a line sample across a dry river valley.  Cambridge IGCSE and O Level Environmental Management b  To find the number of people from each village to or ‘no’, or by a definite answer to the question being be given the questionnaire, we multiply each village asked. Open questions are those which require more sample size 50 thought and require more than a simple one-word population by which in this case is total population 1015 answer. They take longer to record but are useful if more information is required. However the answers Village 1 Village 2 Village 3 might be difficult to record and analysis. Sample size 50 50 50 365 × 233 × 426 × Always thank the respondent once the questionnaire has 1015 1015 1015 been completed. = 17.5 = 11.4 = 20.9 Rounded numbers 18 11 21 An interview involves talking to a small group of people of people to be or an individual. You should have pre-planned questions questioned and the answers are usually longer than those from a questionnaire. Table 0.2 Sample size calculations. A further example of stratified sampling is when soil types Risk assessment are being investigated in an area where 70% of the area To collect data safely, you must be aware of potential consists of rock type A and the remaining 30% consists of health and safety issues relating to the equipment you rock type B. 70% of the soil samples should be taken on are using (e.g. sulfuric acid or a Bunsen burner) or to the rock type A and 30% of the soil samples on rock type B. location of the investigation. You need to decide what equipment you might use and then ensure that the Questionnaires and interviews equipment is tested and, if necessary, calibrated before This data collection method is used when trying to the investigation starts. You should always carry out a obtain people’s opinions. Stratified sampling is used for pilot survey. x questionnaires and careful consideration should be given to the day, time and location when the data are collected Key terms to avoid bias. Pilot survey: a trial run of a survey, which aims to discover any Questionnaires can be carried out by approaching problems with the survey people in the street, knocking on people’s doors, posting Calibrated: to check and make any necessary adjustments questionnaires or, if applicable, placing them on the to a piece of equipment to ensure its accuracy internet. Each method has its own advantages and disadvantages. Can you think what they are? Questions should be pre-planned and it is always Recording data important to do a pilot survey to ensure that the people It is useful to record data in a table format. The table interviewed understand the questions (five respondents should be created before data collection. When drawing would be sufficient), and the answers provide the up a table, remember the following guidelines: information you want to analyse. Always explain the aim When two or more columns are used, the first column of the questionnaire and be polite when asking people to should be the independent variable (i.e. the variable complete them. Stress that the answers will be anonymous chosen by you, the experimenter) and the second and although you should record the age and gender of the and other columns should contain the dependent respondent, remember these are sensitive questions and variable(s) (i.e. the readings taken for each change in should not be asked directly. the independent variable). A good questionnaire should: Columns should be headed with the name of the be carefully worded so people understand the variable and the appropriate unit. questions and questions are not ambiguous Numerical values inserted in the table should just be be quick to complete and therefore have a limited numbers, without units. number of questions in a logical order Practical activity 9.1 in Chapter 9 involves estimating plant have closed questions at the beginning. Closed coverage using quadrats. Table 0.3 is an example of a questions are those which can be answered by a ‘yes’ results table for this activity.  Key skills in Environmental Management Independent variable/ Dependent variable Dependent variable Dependent variable Dependent variable units 1/units 2/units 3/units 4/units Distance/m Species 1/% cover Species 2/% cover Species 3/% cover Species