Paper 2 biology

    Subdecks (1)

    Cards (38)

    • Population
      Species that occupy the same habitat
    • Community

      Populations of different species interacting
    • Ecosystem
      Interaction between biotic and abiotic factors of an ecosystem
    • Food chains
      Feeding relationships between different organisms and the flow of energy between the organisms
    • Biomass
      Total mass of living material
    • Trophic levels
      Stages in a food chain
    • Arrow in food chain represents direction of biomass transfer
    • Primary consumers
      Photosynthetic organisms that use sunlight to make their own food
    • In a stable community

      The number of predators and prey rise and fall in a cycle
    • Producers provide all biomass for the food chain, the rest of the food chain transfers this biomass
    • Belt transect
      Apparatus used to study the distribution of organisms across a gradient
    • Mode
      The most populous organism
    • Median
      The organism that represents the middle value when the organisms are arranged from lowest to highest
    • Material cycle through the living and non-living components of an ecosystem
      1. Organisms take up elements from the surroundings
      2. Elements converted to complex elements which become biomass
      3. Elements transferred along food chains
      4. Elements returned to environment by decomposition and excretion
    • Carbon cycle
      1. Plants release carbon dioxide into the atmosphere through photosynthesis
      2. Organic carbon containing molecules are passed onto organisms that eat the plants
      3. Carbon dioxide is released back into the atmosphere by respiration through animals and plants and from burning fossil fuels
    • Carbon containing molecules such as carbohydrates are needed for organisms to grow and provide energy for vital functions within cells
    • Water cycle
      1. Water from lakes and rivers evaporate
      2. The evaporated water then condenses into clouds and then returned back by precipitation
      3. The water is then back into the rivers and lakes again
    • Living organisms require water and the water cycle provides organisms that live on land a supply of water
    • Microorganisms return carbon to the environment by releasing carbon through respiration while they decompose dead matter. The decomposition of dead matter in soil returns mineral iron to the environment for other organisms to use