General

• Biodiversity


  The variety of the different species on earth or within an ecosystem
• Importance of biodiversity

  • To maintain the stability of an ecosystem
• How biodiversity ensures the stability of an ecosystem

  It reduces the dependence on particular species for resources eg. food and shelter, so that even if one species is removed other species can still survive
• Rapid rise in human population

  Increase in standard of living
• Where pollution occurs

  • Air
  • Land
  • Water
• Water pollutants

  • Sewage
  • Fertiliser
  • Chemicals
• How eutrophication occurs

  1. Fertiliser from farms pollute the water, causing excessive algae growth, depleting the oxygen in the water, causing other plants and animals to die

  2. Dead plants are decomposed by bacteria and the oxygen level decreases further
• Air pollutants

  • Smoke
  • Acidic gases
• Land pollutants

  • Landfill waste
  • Chemicals
• Human activities that reduce the land available for animals and plants

  • Building
  • Farming
  • Quarrying
  • Disposing of waste
• Why peat bogs have been destroyed

  To produce compost to increase food production
• Destruction of peat bogs

  Greatly contributes to the greenhouse effect
• Why the destruction of peat bogs contributes to the greenhouse effect

  Peat bogs are stores of carbon (carbon sinks) and burning them releases a large volume of carbon dioxide into the atmosphere
• Reasons for large-scale deforestation


  • To provide land for cattle or rice fields
  • To grow crops to produce biofuels
• Greenhouse effect


  Greenhouse gases trap energy from the Sun as heat in the atmosphere, keeping the temperature on earth suitable for life
• What is causing global warming


  The increase in levels of greenhouse gases eg. carbon dioxide and methane, causing the temperature on earth to increase
• Harmful effects of deforestation


  • Destruction of many animals' habitats
  • Releases large amounts of greenhouse gases
• Consequences of global warming

  • Rising sea levels
  • Melting polar ice caps
  • Changing weather patterns
  • Migration of animals to find suitable habitats
  • Tropical diseases becoming more common
  • Extinction of species
• Steps taken to maintain biodiversity

  1. Breeding programmes for endangered species

  2. Protection and rebuilding habitats

  3. Replanting field margins and hedgerows

  4. Reduce deforestation

  5. Reduce carbon dioxide emissions

  6. Recycling rather than disposing in landfills
• Purpose of replanting hedgerows and field margins

  There is higher biodiversity in the margins than the fields that they surround