© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 1 1Explain why the human world population has grown. A:More people have been born than died because there was plenty of food, space and other resources needed for living, and better treatment of disease or in childbirth. B1.30 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 2 2Figure B shows three different predictions that the UN has made for human population size in a What are the three predictions? A:Low (7400 million people), Medium (9000 million people), High (10600 million people). B1.30 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 3 b Suggest why the UN made three different predictions. A:Because it is difficult to predict exactly how many people will be born and will die, and the rate of population growth is changing. B1.30 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.30 Questions and answers c Suggest why different estimates give different predictions of human population size in the future. A:They use different estimates of birth rate and death rate over that time, because these are continually changing. Birth rate – death rate = population growth rate. 4

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 5 3Some estimates suggest humans use 60% of available fresh water yearly. Predict how this will change over the next 50 years. A:It is likely to increase because the world human population is still increasing, but at around 50 years it might start to level off. B1.30 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.30 Questions and answers 4Explain why fertiliser use is increasing. A:The human population is still increasing. More people need more food and fertilisers help crops to produce more food, so we need to use more fertilisers. © Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 6

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.30 Questions and answers 5Draw a flowchart to show how eutrophication is caused and how it can damage the environment. A:Diagram that includes the following correctly linked: fertilisers containing nitrates and phosphates  get into water surrounding fields  increased nutrients increases plant growth in water  plants block light from water below them  plants deeper in water can't get enough light and die  decay organisms break down dead plant tissues  as decay organisms respire they take oxygen from water  as oxygen concentration in water falls, animals can't get enough oxygen and die. 7

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.30 Questions and answers 6Explain in as much detail as you can why increasing population growth and industrialisation of a country could lead to increased pollution. A:More industrialisation means making more products, using more resources and usually burning more fossil fuels. If we are not careful to clean up the waste from these processes then we cause more pollution. A bigger population also needs more food, requiring more use of fertilisers and so a greater risk of eutrophication. 8

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 9 1Explain the term ‘indicator species’. A:An indicator species is a species whose presence or absence indicates the presence or absence of pollution. 2Why is clean air not good news for rose growers? A:Sulfur pollution in the air kills the fungus that causes blackspot disease on roses. So clean air means more fungus and more rose disease. B1.32 Questions and answers

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. 10 3Name two indicator species of clean water and two of polluted water. B1.32 Questions and answers Indicators of clean waterIndicators of polluted water stonefly larvaeblood worms freshwater shrimpssludgeworms

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.32 Questions and answers 4A Why do animals need oxygen? A:Animals use oxygen in respiration to release energy for all living processes. Without oxygen they will die. b Suggest why plants are not used as indicators of water pollution. A:Plants produce oxygen in photosynthesis so the oxygen they need for respiration is not limited to what is already there. 11

© Pearson Education Ltd Copying permitted for purchasing institution only. This material is not copyright free. This document may have been altered from the original. B1.32 Questions and answers 5Suggest why running out of gallium would be a problem. A:We will not be able to make flat-screen TVs in the same way as we do now. 6Describe fully the advantages of recycling. A:Recycling reduces our use of new resources and any pollution linked to getting them. It also reduces the use of land for waste disposal and any pollution from the waste. 12