ecology

• food chain is showing the transfer of energy from one organism to the next, beginning with a producer
• food web is a network of interconnected food chains
• producer is an organism that makes its own organic nutrients, using energy from photosynthesis
• consumer is an organism that gets its energy by feeding on other organisms
• herbivore is an animal that gets its energy by eating plants
• carnivore is an animal that gets its energy by feeding on other animals
• decomposer is an organism that gets its energy from waste or dead organic matter
• ecosystem is a unit containing all of the organisms and their environment interacting together in a given area
• trophic level is the position of an organism in a food chain or a food web
• photosynthesis is the process by which plants manufacture carbohydrates using from raw materials using light energy
• Carbon dioxide is a greenhouse gas. This means that it traps heat in the Earth’s atmosphere. 
• Forests are ‘sinks’ for carbon dioxide: this means that they absorb most of the carbon dioxide produced by respiration and decomposition. Without these forests, the atmospheric carbon dioxide concentration will increase even more rapidly.
• Deforestation can cause:

  • species extinction
  • soil erosion
  • flooding
  • increased carbon dioxide in the atmosphere.
• sources of pollution of water: chemical waste, discarded rubbish, untreated sewage and fertilisers.
• If too much fertiliser is used, nutrients such as nitrates and phosphates will be washed into nearby water (lakes, streams, etc.). These nutrients cause eutrophication:

  • The nitrates and phosphates encourage the growth of algae.
  • The algae form a bloom on the surface of the water, which prevents sunlight from reaching other water plants.
  • The water plants die and are broken down by bacteria.
  • The bacteria use up the oxygen in the water, so other organisms die.