7.3

• What is biodiversity?

  The variety of different species on Earth
• Why is biodiversity important?

  It maintains the stability of an ecosystem
• How does biodiversity ensure ecosystem stability?

  It reduces dependence on particular species
• What are two reasons for increased human consumption of resources?

  Rapid rise in population and living standards
• Where does pollution occur?

  Air, land, and water
• Name an example of water pollutants.

  Sewage, fertilizer, and chemicals
• How does eutrophication occur?

  Fertilizer pollution causes excessive algae growth
• State an example of air pollutants.

  Smoke and acidic gases
• State an example of land pollutants.

  Landfill waste and chemicals
• Which human activities reduce land for animals and plants?

  Building, farming, quarrying, and waste disposal
• Why have peat bogs been destroyed?

  To produce compost for food production
• How does the destruction of peat bogs contribute to the greenhouse effect?

  It releases carbon dioxide into the atmosphere
• Why have large-scale deforestation activities occurred?

  To provide land for cattle and crops
• What is the greenhouse effect?

  Greenhouse gases trap energy from the Sun
• What is causing global warming?

  Increase in greenhouse gases like CO2 and methane
• What are the harmful effects of deforestation?

  Destruction of habitats and greenhouse gas release
• What are the consequences of global warming?

  Rising sea levels and changing weather patterns
• What are the steps taken to maintain biodiversity?

  • Breeding programmes for endangered species
  • Protection and rebuilding habitats
  • Replanting field margins and hedgerows
  • Reduce deforestation
  • Reduce carbon dioxide emissions
  • Recycling instead of landfilling
• What is the purpose of replanting hedgerows and field margins?

  Higher biodiversity in the margins than fields