1- Ecosystems

• Ecosystem


  A relatively self-contained community of interacting organisms and the environment they live in, and interact with
• Ecosystems


  • There is a flow of energy within an ecosystem and nutrients within it are recycled
  • There are both living (biotic) components and non-living (abiotic) components within an ecosystem
  • Ecosystems vary greatly in size and scale
  • Ecosystems vary in complexity
• Ecosystems


  • A small pond in a back garden
  • The open ocean
  • An individual human being
  • A desert
  • A tropical rainforest
• No ecosystem is completely self-contained as organisms from one ecosystem are often linked to organisms from another
• Biotic factor


  Anything that influences the populations within a community that is a result of another organism's activity
• Examples of biotic factors

  • Predation
  • Competition (inter-specific) for space, food, water, light etc.
  • Cooperation between organisms (can be between the same species or different species)
  • Parasitism
  • Disease
  • Camouflage
  • Mimicry
  • Mankind
• Abiotic factor


  Any physical or chemical factor (non-living) that influences the populations within a community
• Examples of abiotic factors

  • Availability of water
  • Light
  • Radiation
  • Temperature
  • Turbidity ('cloudiness') of water
  • Humidity
  • Atmospheric composition
  • pH
  • Salinity
  • Soil composition