biodiversity (human)

• polluting water with fertiliser and sewage

  • farmers spread fertiliser on fields.
  • rain washes fertiliser into rivers and ponds
  • sewage is released directly into rivers
  • fertilisers and sewage cause an increase in growth of algae.
  • when the algae die they are decomposed by bacteria that use oxygen
  • other animals die due to a lack of oxygen
• using land

  • humans construct buildings, create quarries and farm
  • habitat for plants and animals is reduced
• destroying peat bogs

  • humans use peat to provide compost to increase food production
  • removes habitat, reducing biodiversity
  • decay or burning of peat produces carbon dioxide
• deforestation

  • to provide land for cattle and rice fields
  • to grow crops for biofuel
  • burning or decomposing trees releases carbon dioxide
  • fewer trees to remove carbon dioxide from the atmosphere
  • less biodiversity
• producing acidic gasses

  • combustion of fossil fuels releases carbon dioxide, sulphur dioxide and nitrogen oxides
  • these gases dissolve in water making it acidic
  • acid rain
  • damages plants
  • can cause rivers or lakes to become acidic, killing plants and animals
• polluting water with toxic chemicals

  • pesticides and other toxic chemicals (e.g. from landfill) are washed into rivers and lakes by rain
  • toxic chemicals accumulate in animals
  • the further up the food chain, the greater the accumulation
  • top predators die or fail to breed
• increasing global warming

  • humans release extra greenhouse gases (carbon dioxide and methane) into the atmosphere and less carbon dioxide is absorbed by plants through photosynthesis
  • greenhouse gases absorb heat and stop it escaping into space
  • loss of habitat as sea levels rise; animals and plants can no loger survive in certain areas; reduced biodiversity; change in migration patterns of animals