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Environmental biology

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Environmental biology

  1. 1. Topic deals with how humans affect the environment In a negative way In a positive way
  3. 3. Extinction is when a species no longer exists Species: a group of organisms that are able to interbreed and produce fertile offspring.
  4. 4. An increase in human population affects the environment in 3 ways: 1.Agriculture 2.Housing 3.Industries
  5. 5. 1. Intensification of agriculture  forests are cut down to plant crops
  6. 6. 1. Intensification of agriculture  Pesticides and fertilisers are applied
  7. 7. How do pesticides and fertilisers end up in the sea?
  8. 8. 2. Urbanisation  land is lost to build towns
  9. 9. 2. Urbanisation  problems in refuse and sewage disposal  disease may result
  10. 10. 2. Urbanisation  burning of fossil fuels for:  heating & transport pollute the air
  11. 11. Fossil fuels are: coal oil Natural gas [methane is major component]
  12. 12. 3. Industrialisation  more factories more pollution
  13. 13. Soil erosion means that soil is: blown away by the wind or washed away by rainwater
  14. 14. Three causes of soil erosion: 1. deforestation – cutting down of trees
  15. 15. Three causes of soil erosion: 2. bad farming methods – crop rotation not used – heavy use of artificial fertiliser
  16. 16. 3. Overgrazing – herbivores are allowed to graze very often in the same field
  17. 17. Soil erosion leads to: desertification :the land cannot be used for agriculture
  18. 18. Three ways to reduce soil erosion: 1. contour ploughing - ploughing around hill instead of up-down Ploughing vertically increases soil erosion. Contour ploughing reduces soil erosion.
  19. 19. Water settles in furrows.
  20. 20. 2. strip cropping alternate strips of crops are planted in the same field
  21. 21. Crops are planted: 2. at right angles to the wind direction. 1. following the natural contours of the land.
  22. 22. 3. terracing
  23. 23. Is it a good idea to build a brick wall instead of a rubble wall? no
  24. 24. Why do farmers quickly rebuild rubble walls after damage by rain?
  25. 25. Monoculture is when one type of crop is grown over a large area
  26. 26. Advantage of monoculture:  land can be used intensively, that is more food for more people
  27. 27. Disadvantages of monoculture: 1. trees had to be cut down so the natural environment is destroyed; biodiversity is reduced
  28. 28. 2. repeated ploughing and the use of artificial fertilisers damage the soil
  29. 29. 3. a pest spreads quickly as plants are close together and natural predators are killed by pesticides.
  30. 30. Question: SEP, 2008 Monoculture is a farming method that involves growing one type of crop over a large area. Suggest TWO negative effects of this method on the environment. (4 marks) 1. Favours spread of pests that thrive on the crop plant. 2. Reduces biodiversity (directly or indirectly)
  31. 31. Why are trees cut down? 1. to clear the land to build houses, roads and factories 2. to convert the forest into agricultural land 3. to use the wood from trees as a fuel 4. wood is used as a building material
  32. 32. 5 harmful effects of deforestation: 1. Imbalance in the water cycle  less rain forms in deforested areas due to less transpiration
  33. 33. 2. Has a severe impact on soil – roots & leaves no longer protect the soil.
  34. 34. 3. Drives countless plant and animal species to extinction – due to loss of habitat and food. Loss of biodiversity
  35. 35. Biodiversity: the variety of life on Earth Monoculture: LOW biodiversity Forest: HIGH biodiversity
  36. 36. 4. CO2 levels rise, contributing to the greenhouse effect (global warming).
  37. 37. 5. A valuable natural source is wasted e.g. seeds, fruit, rubber, resins rubber resin
  38. 38. Cellulose can be used to make threads. Threads are woven into cloth. Cellulose Dress made of viscose. Mop made of viscose.
  39. 39. Explain the poster. How can trees be saved? Recycle paper
  40. 40. 5. A valuable natural source is wasted e.g. medicinal compounds.
  41. 41. Afforestation: the planting of trees
  42. 42. Question: SEP, 2009 Give a biological explanation for each of the following statements: It is estimated that deforestation will increase in the coming years. (3) Human population is estimated to increase. Forests are cleared to make way for houses, roads , factories and to grow crops. Trees are cut as a source of wood as fuel or building material.
  43. 43. Question: SEP, 2010 Give a biological explanation for each of the following statements. If trees are cut down in an area, there will be a reduction in the bird population. (3) Birds lose their natural habitat and source of food. They sleep on the branches, hide from predators and seek shelter on trees.
  44. 44. Pollution  is any process which leads to a harmful increase in the amount of a chemical substance in the environment
  45. 45. Pollutants are harmful  Pollutants can be:  substances  energy Light pollution Noise pollution
  46. 46. Three types of pollution: 1. Air 2. Water 3. Land
  47. 47. Air pollution:  Lead  Chlorofluorocarbons [CFC’s]  Carbon dioxide & carbon monoxide  Oxides of nitrogen & sulfur dioxide
  48. 48. Air pollution:  Lead  Chlorofluorocarbons [CFC’s]  Carbon dioxide & Carbon monoxide  Oxides of nitrogen & sulfur dioxide
  49. 49. Lead  Leaded petrol:  lead - antiknock  lead ends up in air from car exhaust  Lead harms the brain & liver of young children  Malta stopped using leaded petrol in Jan 2003 and lead replacement petrol (LRP) in Jan 2011
  50. 50. Question: MAY, 2011 (2B) Give a biological explanation for each of the following statements. Most cars now run on unleaded petrol and leaded petrol is becoming less readily available. (5) Most cars run on unleaded fuel because lead compounds in fuel are absorbed into the body from inhaled air and may slow down mental development and damage the liver.
  51. 51. Air pollution:  Lead  Chlorofluorocarbons [CFC’s]  Carbon dioxide & Carbon monoxide  Oxides of nitrogen & sulfur dioxide
  52. 52. Chlorofluorocarbons (CFC’s)  liquefy when compressed  were invented in 1928 – very unreactive  some CFC’s have a lifespan of up to 75 years!  used as refrigerants, propellants in aerosol cans and plastic foams
  53. 53. CFC’s destroy the ozone layer (O3)
  54. 54. Role of the ozone layer: absorbs UV rays
  55. 55. Chlorine in CFC’s changes: ozone into oxygen and keeps on doing this
  56. 56. What happens if the ozone layer is destroyed? Solar UV rays Solar UV rays
  57. 57. Destruction of the ozone layer: 1. leads to increased ultraviolet radiation which:  causes skin cancer  damages plants 2. interferes with the O2 cycle 3. distorts weather patterns Increase in ozone hole over the years.
  58. 58. To avoid damage by CFC’s: 1. use ozone-friendly products 2. ban of products containing substances that damage the ozone layer
  59. 59. Question: MAY, 2011 (2B) Give a biological explanation for each of the following statements. In many countries aerosols containing chlorofluorocarbons (CFC’s) have been reduced. (5) CFCs are very unreactive compounds that spread through the atmosphere without reacting with other substances and drift into the upper atmosphere. There they meet ozone that oxidises CFCs and in doing so is converted into oxygen. This is causing thinning of the ozone layer that protects animals and plants from ultraviolet radiation. Thus countries are taking measures to reduce the use of CFCs.
  60. 60. Air pollution:  Lead  Chlorofluorocarbons [CFC’s]  Carbon dioxide & Carbon monoxide  Oxides of nitrogen & sulfur dioxide
  61. 61. Burning of fossil fuels produces:  SOOT:  Blackens buildings  Reduces photosynthesis  Causes irritation of lungs
  62. 62. Carbon dioxide is  released when burning fossil fuels  a greenhouse gas  contributes to the greenhouse effect
  63. 63. Air warms up inside a greenhouse
  64. 64. The Greenhouse Effect Some sunlight that hits the earth is reflected. Some becomes heat. Some sunlight that hits the earth is reflected. Some becomes heat. Greenhouse gases in the atmosphere trap heat, keeping the air warm.
  65. 65. The greenhouse effect
  66. 66. Methane is also a greenhouse gas
  67. 67. Ice melts as temperature rises  some animals lose their habitat
  68. 68. How can a rise in air temperature be: 1. helpful to plants?  Higher rate of photosynthesis 2. harmful to plants?  Lose water and wilt.
  69. 69. Mention 4 ways of how release of greenhouse gases can be reduced from passenger vehicles
  70. 70. 1. Increase number of car-free days 2. Use public transport
  71. 71. 3. Encourage car-sharing
  72. 72. 4. Encourage people to use the bicycle. - provide lanes & parking places
  73. 73. Carbon monoxide  combines with haemoglobin instead of oxygen  Result:  less oxygen in blood
  74. 74. Air pollution:  Lead  Chlorofluorocarbons [CFC’s]  Carbon dioxide & Carbon monoxide  Oxides of nitrogen & sulfur dioxide
  75. 75. Sulfur dioxide and oxides of nitrogen  form on burning fossil fuels  the gases dissolve in rainwater and form ACID RAIN
  76. 76. Acid rain has many harmful effects
  77. 77. Effects of Acid rain:  dissolves limestone
  78. 78. Effects of Acid rain:  reduces the growth of plants and damages leaves
  79. 79. Effects of Acid rain:  makes lakes acidic, killing fish and invertebrates
  80. 80. Question: SEP, 2008 A recent study showed that the water in the river is acidified. A characteristic feature of acidified water in rivers is the slow rate of decomposition of organic matter. Explain. (3 marks) Decomposers like bacteria function best at an optimum pH. At an acidic pH, decomposition occurs slowly.
  81. 81. Effects of Acid rain:  dissolves out nutrients, leaving the soil infertile
  82. 82. Question: MAY, 2011 (2B) Give a biological explanation for each of the following statements. Many industries are using sulfur-free fuel. (5) Sulfur-free fuel reduces the emission of sulfur dioxide in the atmosphere; thus this reduces the risk of acid rain caused by sulfuric acid and other acids.
  83. 83. To reduce pollutants in air, cars are fitted with: 1. Filters – diesel engines
  84. 84. 2. catalytic converters – petrol engines Normal exhaust consists of:  unburnt petrol  carbon monoxide  oxides of nitrogen The catalytic converter causes a reaction between these badly polluting exhaust gases to produce harmless gases which include:  nitrogen  oxygen  carbon dioxide  water vapour
  85. 85. To reduce pollutants in air, chimneys are fitted with filters
  86. 86. Renewable & Non-renewable  renewable energy sources:  can be replenished (made again) naturally [e.g. solar and wind energy]  nonrenewable energy sources:  cannot be replenished in a short period of time[fossil fuels]
  87. 87.  Clean energy
  88. 88. Non-renewable energy  Cause of air pollution
  89. 89. Solar energy Wind energy
  90. 90. Water pollution:  Sewage  Fertilisers  Pesticides  Oil Raw sewage: Bangkok
  91. 91. Sewage  may contain bacteria which cause cholera and typhoid  if the bacteria enter drinking water the disease spreads to many people
  92. 92. Sewage & fertilisers :  contain nitrates & phosphates  both cause: the enrichment of natural waters with nutrients which allow great growth of algae
  93. 93. Plants need nitrates & phosphates to produce proteins More proteins = More growth
  94. 94. Algal bloom Satellite image
  95. 95. Eutrophication
  96. 96. Dead fish in China [2010]
  97. 97. Question: MAY, 2009 Give a biological explanation of the message in the poster: Eutrophication leads to algal blooms. Algae die and are decayed by bacteria. Bacteria use oxygen from the water, causing fish and other aerobic organisms to die.
  98. 98. Is there a way to make sewage safe to pour into the sea? Use a sewage treatment plant.
  99. 99. Saprophytic bacteria in sewage treatment plants remove harmful nutrients from raw sewage An aerial view of the Gozo sewage treatment plant
  100. 100. Sant’ Antnin Sewage Treatment Plant [Marsascala]
  101. 101. Fig. 6 A sewage treatment plant. Sludge: solid part Effluent: liquid part
  102. 102. First settling tank
  103. 103. Sludge may be:  dumped into the sea  dried for fertiliser  fermented to make methane gas
  104. 104. Malta: Water from sewage treatment used for plant irrigation
  105. 105. What happens to the effluent? EFFLUENT sea irrigation
  106. 106. Sewage at Mellieha [2009]
  107. 107. Question: MAY, 2012 Ta’ Barkat sewage treatment at Xghajra has significantly reduced the amount of raw sewage disposed at sea. a) Air is pumped in one of the sewage tanks where bacteria are metabolically active. Explain the importance of this process. (2) b) Give TWO reasons why it is important to reduce raw sewage disposal at sea. (4) c) Describe ONE way how the pumped water by-product of sewage treatment may be used. (1)
  108. 108. Water pollution:  Sewage  Fertilisers  Pesticides  Oil
  109. 109. Fig. 7 How fertilisers reach the groundwater. runoff
  110. 110. To avoid contamination of ground-water: i) use natural fertilisers as these are less soluble ii) do not over-apply fertiliser
  111. 111. Water pollution:  Sewage  Fertilisers  Pesticides  Oil
  112. 112. Pesticides are chemicals that kill pests
  113. 113. Pesticides can be: 1. Persistent:  remain active for a long time after they have been released e.g. DDT 2. Non-persistent:  break down in the environment soon after they have been released
  114. 114. Harmful effects of pesticides: 1. Can kill beneficial organisms.
  115. 115. 2. Can build up along the food chain, killing the top carnivore.
  116. 116. 3. Causes water pollution.
  117. 117. 4. Causes insects to become resistant to the pesticide.
  118. 118. DDT & dieldrin are now banned from most countries
  119. 119. What is ‘organic food’? Food that is produced using methods that do not involve pesticides and chemical fertiliser.
  120. 120. We can get rid of pests by: 1. Chemical control:  spray with chemicals 2. Biological control:  making use of other organisms which kill the pest
  121. 121. Examples of biological control Fig. 9 Wasps are used to kill caterpillars.
  122. 122. Ladybirds feed upon aphids (greenflies)
  123. 123. Fish eat larvae of mosquito
  124. 124. Biological control gone wrong: Cane toads in Australia
  125. 125. Advantages of biological control: 1. it avoids polluting the environment 2. pests never develop resistance to it
  126. 126. Disadvantages of biological control: 1. the introduced organism dies out as the environment does not suit it 2. the control agent may eat up all the pests and then starts eating a useful species
  127. 127. Water pollution:  Sewage  Fertilisers  Pesticides Oil
  128. 128. Oil spillages from tankers cause harm
  129. 129. What is the effect of an oil spill on birds and fish?
  130. 130. Birds die: too heavy to fly
  131. 131. Fish die: gills become clogged with oil Dead fish in a clump of oil [2010]
  132. 132. Beaches are spoilt
  133. 133. Seashore animals & plants become covered with oil
  134. 134. What about plastic at sea?
  135. 135. Plastic in the sea harms animals
  136. 136. Land pollution: 3. Land pollution:  dumping of rubbish
  137. 137. Waste Management involves:  the collection and transportation of materials from households, businesses, schools and so on, to be processed or disposed of
  138. 138. Landfill is the most common method of waste disposal all over the world Landfill involves dumping waste in unused/unwanted sites such as disused quarries
  139. 139. In order to fit more in:  rubbish in landfill sites is regularly squashed  soil is added – why? 1. To reduce odour 2. Prevent lightweight waste from becoming litter
  140. 140.  this squashing, removes air which leads to the landfill becoming anaerobic (without air)  methane gas is produced
  141. 141. What can be done for a landfill to take long to become full?  Burning  Compressing  Extracting certain materials for reuse
  142. 142. Remember the 3R’s with regards to waste management
  143. 143. Some landfill sites are engineered  To capture methane  methane is used to generate energy
  144. 144. What is an ‘engineered landfill’?  landfill is lined with plastic to prevent leaching
  145. 145. Plastic lining at a landfill
  146. 146. Engineered landfill at Maghtab
  147. 147. 1. Rotting rubbish emits explosive gases and polluting liquids.
  148. 148. Toxins leach out of the landfill & contaminate the sea
  149. 149. 2. Visual pollution
  150. 150. 3. Rotting rubbish:  produces an odour  encourages pests
  151. 151. Question: MAY, 2010 The Yelkouan Shearwaters (il-Garnija) is a special bird for Malta. Several of these birds breed at Rdum tal- Madonna in L- Aħrax tal- Mellieħa.
  152. 152. Describe how each of the following threats lead to a decrease in the population of Yelkouan Shearwaters: i) uncollected rubbish from the camping site at L- Aħrax tal-Mellieħa; (3) Rubbish leads to a proliferation of rats these will kill the chicks therefore population in number. Also prevent them from reaching sexual maturity and breeding.
  153. 153. ii) loud music on lit boats during boat parties. (2, 2) Loud music prevents communication between birds. The light and loud music interfere with reproduction, thus fewer eggs are laid. This results in a decrease in the population.
  154. 154. iii) Pushing old cars off the cliffs. (3) The cars may close entrances to burrows where the birds nest therefore they do not breed.
  155. 155. Question: MAY, 2009 Discuss the environmental disadvantages of:  dumping of rubbish. (3) Dumping sites have an impact on the surroundings – unsightly rubbish and impact of smells; dumping sites can attract pests such as flies and rats and these spread disease; damage to air pollution from possible burning of items; ground water and run off pollution; habitat destruction. Accept any reference to dumping in the sea/nonbiodegradable rubbish
  156. 156. Fish farming is the:  rearing of aquatic organisms under controlled conditions Started in 1980’s in Malta
  157. 157. Fish can be grown in tanks on land Guatemala
  158. 158. in nets in the sea
  159. 159. Malta farms 84% of all the fish it produces
  160. 160. Bluefin tuna are caught from the sea and fattened in cages Bluefin tuna Towing a cage with bluefin tuna
  161. 161. What are ‘fish stocks’? Fish growing naturally at sea.
  162. 162. Eggs from females are fertilised & the young fish are grown Advantage: Natural fish stocks are conserved
  163. 163. Reared fish are intended for: 1. food (have a high protein content) Sea bream (awrat) Sea bass (spnott)
  164. 164. Reared fish are intended for: 2. recreation (when lakes are restocked with fish for fishing as a hobby) Fish farmer releases carp into the lake
  165. 165. What can be grown on a fish farm?  Fish  Lobsters  Shrimps  Oysters  Mussels  Algae Oyster fish farm
  166. 166. Algae are grown for food
  167. 167. Seaweed may become an abundant source of biofuels.
  168. 168. More fish can be grown on a fish farm than in nature, in the same volume of water But fish must be fed!!
  169. 169. Is all the food eaten by the fish?
  170. 170. A fish farm causes damage to the environment by: 1. Fish waste 2. uneaten food
  171. 171. Advantages of fish farming: 1. Fish do not move much and so are more efficient in converting food into biomass 2. Fewer lost to predation 3. Conservation of wild fish stocks 4. Easier to catch 5. Food quality can be controlled 6. Can be genetically engineered
  172. 172. Disadvantages of fish farming: 1. Disease is more likely 2. More antibiotics are thus used 3. High cost of food 4. Expensive to set up 5. Pollution of environment by uneaten food and fish wastes 6. Food chain is affected due to pollution
  173. 173. Question: MAY, 2012 (2A) Comment on the biological significance of each of the following statements. Fish farming is a possible way of limiting the decrease in fish stock, however it has a number of disadvantages. (5) Fish farming can help to limit the decrease in fish stock by farming species of fish under captive conditions. (2 marks) However fish farming has a number of disadvantages including: spread of disease higher than normal, excessive use of antibiotics, pollution from the fish waste, excessive use of pesticides to control parasites affecting fish, farmed fish may escape and compete for food with wild fish; may be fed on fish meal made from wild fish. (3 marks) (Award 1 mark each for each disadvantage mentioned.)
  174. 174. What is ‘conservation’? To conserve something means to protect it and keep it in a healthy state.
  175. 175. Ways to conserve the environment: 1. Setting up of nature reserves to protect endangered species
  176. 176. What are ‘endangered species’? Endangered species are present in small numbers that risk extinction. e.g. of endangered species in Malta: Great white shark Basking shark A great white shark was caught in Malta by Alfredo Cutajar in April 16, 1987. This shark was also estimated to be around 7.13 m (24 ft).
  177. 177. Ways to conserve the environment: 2. Setting up laws to prevent overhunting and overfishing. Police stop illegal bird trapping in Malta
  178. 178. Overhunting/overfishing is when more individuals are caught than nature can replace Bison skulls (1890)
  179. 179. Overhunting/overfishing is when more individuals are caught than nature can replace Overfishing of cod.
  180. 180. What are ‘protected species’? Species that cannot be caught, sold or killed Examples:  Dolphins  Turtles  Frogs Narcissus Loggerhead turtle [Narcis]
  181. 181. Maltese Rock Centaury Widnet il-Bahar Blue Rock Thrush 'Merill' Sandarac gum tree is- Sigra tal-Gharghar
  182. 182. Ways to conserve the environment: 3. Helping rare animals to reproduce in zoos to prevent their extinction. Artificial insemination of a panda in a zoo.
  183. 183. Ways to conserve the environment: 4. When fishing, nets must have large holes to let the young escape.
  184. 184. Ways to conserve the environment: 5. Damaged rubble walls must be rebuilt to:  prevent soil erosion  conserve the wild life living in them
  185. 185. Il-Buskett is considered as an area of ecological importance: 1. Many trees are present = many types of birds
  186. 186. 2. There is a freshwater stream in which many species live. Such streams are not common in the Maltese Islands. Wied il-luq
  187. 187. Question: SEP, 2009 Give a biological explanation for each of the following statements: Human activities can lead to extinction in many ways. (5) Extinction is when a species does not exist any more. Humans destroy the natural habitat of plants and animals by:  cutting down of trees  overhunting and overfishing  changing the climate due to global warming
  188. 188. Question: SEP, 2009 Give a biological explanation for each of the following statements: Shipping adds pollutants to oceans. (3) Ships may release raw sewage into the ocean. Tankers may accidentally spill oil. People on ships may dump plastic or other solid waste.
  189. 189. What is the main problem related to the conservation of agricultural land in the Maltese Islands? There is so little of it, that it is overused with the possible risk of soil erosion.
  190. 190. THE END