Biodiversity

• Biodiversity - the variety of different species within an ecosystem.
• Environmental changes which affect the distribution of species;

  • Temperature
  • Availability of water
  • Atmospheric gas composition

  These changes may be caused by seasonal, geographical or caused by human interaction.
• If there is a high biodiversity in the ecosystem then it will be stable. This is because the species are less dependent on each other.
• Human activity which can affect biodiversity;

  • More land is used, for farming, houses, shops etc - this destroys habitats
  • Pollution from sewage, fertilisers, land fill and different gasses - kills plants and animals
  • Using up raw materials quicker than they are produced.
• Ways of improving biodiversity;

  • Breeding programmes
  • Protected areas
  • Reducing water pollution
  • Replanting hedgerows and woodlands to provide habitat
• Reasons to prevent extinction/maintain biodiversity;

  • Organisms may produce useful substances (e.g. medicine)
  • Have a duty to preserve
  • Provides resources for future generations
  • May affect other organisms
  • Cause a loss of environmental indicators
• Air pollution is due to poisonous gases, like sulphur dioxide, carbon monoxide.
• Water pollution due to fertillisers and toxic chemicals.
• Land pollution due to herbicides and toxic waste.
• Eutrophication is when sewage or fertiliser gets into water. This causes lots of algea to bloom, which is in a very dense layer.

  This means that no sunlight can get into the water and to the plants underwater, so they will be unable to photosynthesis.

  As a result, no oxygen is being produced, so marine organisms will start to die out and it will become a death zone.
• Examples of seasonal changes;

  • Temperature
  • Rainfall
  • Water availability
  • Gases dissolved in water
  • Number of daylight hours

  These affect distribution and growth in plants and migration of animals.
• Examples of geographical changes;

  • Soil
  • Altitude
  • Saltiness of water
  • Availability of water

  Plant and animals have adaptations to deal with these.
• Human interaction changes;

  • Deforestation
  • Burning fossil fuels
  • Farming
  • Hunting
  • Plastic waste