Organisms & their environment ( 1 )

• Energy flow


  Energy flows through living organisms starting with the Sun, plants use light energy from the Sun to make their own food storing it as chemical energy in their cells, animals then eat the plants gaining energy from them, this energy is passed on when animals are eaten by other animals, eventually energy is returned to the environment through decomposition
• Producer


  An organism that makes its own organic nutrients usually using energy from sunlight through photosynthesis
• Consumer


  An organism that gets its energy by feeding on other organisms
• Herbivore


  An animal that gets its energy by eating plants
• Carnivore


  An animal that gets its energy by eating other animals
• Decomposer


  An organism that gets its energy from Dead or waste organic material
• Consumers


  • Primary
  • Secondary
  • Tertiary
  • Quaternary
• Food chain


  Shows the transfer of energy from one organism to the next beginning with a producer, the arrows between each organism in the chain always point in the direction of energy flow from the food to the consumer
• Food web


  A network of interconnected food chains
• Trophic level


  The position of an organism in a food chain, food web or ecological pyramid
• Trophic levels


  • Producers
  • Primary consumers (herbivores)
  • Secondary consumers (predators that feed on primary consumers)
  • Tertiary consumers (predators that feed on secondary consumers)
  • Quaternary consumers (predators that feed on tertiary consumers)
• Human impact on food chains and food webs

  Over harvesting of food species disrupts the food chains because the organisms that eat these species won't have enough food to survive, leading to population declines, introduction of foreign species to a habitat creates competition for resources which can harm the existing species and disrupt the food chain
• Pyramid of numbers


  Shows the number of organisms in each trophic level of a food chain
• Pyramid of biomass


  Shows the total mass of organisms in each trophic level of a food chain rather than the number of organisms
• Pyramid of energy


  Shows the flow of energy at each trophic level in an ecosystem, 90% of the original energy is lost at each trophic level, only 10% of the energy is available to the organism at the next trophic level
• Food chains usually have fewer than five trophic levels because there is significant energy loss at each level, making it difficult to sustain higher trophic levels
• It is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants, because energy is lost at each trophic level when we consume livestock