HideShow resource information
View mindmap
  • Ecosystems
    • Closed loop system
      • All natural ecosystems are closed loop systems
      • In a perfect closed loop system no materials enter or leave the system.
      • Output of one becomes input of another
      • No ecosystem can be a perfect one as some input is lost
    • linear system
      • the waste products do not get feeded back as food products
      • you have to add new products to keep it going
    • waste products
      • oxygen is a waste product in photosynthesis used in respiration
      • Carbon dioxide is a waste product from respiration. It is used in photosynthesis.
      • Dead organic matter  is used directly as food or processed into useful nutrients by microorganisms.
    • nitrogen cycle
    • carbon cycle
    • damage to ecosystems by humans
      • agricultural waste
        • harvesting plants and animals can damage an ecosystem
        • harvesting timber can lead to soil erosion and loss of habitat
        • over fishing can damage ecosystems and cause the to become extinct
        • loss of hedges means less habitat for the birds
        • fertilisers get washed into rivers and kill animals
      • industrial waste
      • green house gases
      • household waste
      • bio-fuels destroy habitat and decrease biodiversity
        • lack of shade and the lack of moisture in the soil can cause desertification (when fertile land turns into relatively lifeless desert).
    • reproductive strategies
      • fish and amphibians  produce large numbers of eggs because fertilisation takes place outside the body.
      • When organisms produce large numbers of reproductive cells or reproductive structures, these ensure that reproduction is likely to be successful.
      • The unsuccessful cells are recycled into the ecosystem. They are usually used as nutrients for animals or microorganisms.
    • vegetation
      • it is important because it is used in photosynthesis
      • roots help stabilise soil
      • Trees provide shade from the sun and help to insulate the forest floor at night
      • Transpiration from trees helps to promote cloud formation.
    • sustainability
      • examples
        • Fish populations can be preserved if quotas are observed, which means that each country has an entitlement to catch only a certain number of each type of fish.
        • using biofuels - A biofuel is a fuel produced from renewable resources - such as plant biomass
        • Forests can be preserved if the trees are replanted
    • bioaccumulation
      • Is when toxins build up in a food chain.
      • The animals at the top of the food chain are affected most severely.
    • Eutrophication
      • When fertilisers are added to farmland in large quantities, plants and animals in nearby rivers and lakes can sometimes be killed, but not by poisoning.


No comments have yet been made

Similar Science resources:

See all Science resources »See all Biology resources »