Ecosystem

• Source of energy in all ecosystems

  The sun
• How green plants convert energy

  1. Convert light energy from the sun into chemical energy (food) through photosynthesis

  2. Chemical energy transferred to primary consumers

  3. Transferred to secondary and tertiary consumers in the food chain and food web
• Organisms in an ecosystem

  • Producers
  • Consumers
  • Decomposers
• Producers


  Green plants that produce their own food through photosynthesis
• Types of consumers


  • Primary consumers
  • Secondary consumers
  • Tertiary consumers
• Primary consumers


  Eat producers (plants) and are normally herbivores and omnivores
• Secondary consumers


  Eat primary consumers and are normally omnivores and carnivores
• Tertiary consumers


  Eat secondary consumers and are mostly carnivores
• Decomposers


  Break down dead animals and plants into simpler materials or nutrients, e.g. mushrooms and bacteria
• Saprophytism


  The interaction between decomposers and dead organisms
• Decomposers


  • Mushrooms
  • Bacteria
• Food chain


  1. Shows feeding relationships between organisms

  2. Energy flows from producers to consumers
• The arrow in a food chain represents the flow of energy
• In a food chain, the producer is eaten by the primary consumer, which is then eaten by the secondary consumer, and so on
• Food web


  Formed by combining multiple food chains
• Energy is not completely transferred from one organism to the next in a food chain/web
• Energy is lost through movement, respiration, undigested food/faeces
• Symbiosis


  An interaction when two or more organisms of different species live very closely together and interact with each other
• Types of symbiosis


  • Mutualism
  • Commensalism
  • Parasitism
• Mutualism


  An interaction or relationship that benefits both organisms living together
• Examples of mutualism


  • Clownfish and sea anemone
  • Fungi and algae (lichen)
  • Miner bird and buffalo
• Commensalism


  An interaction where one organism benefits while the other is neither harmed nor benefited
• Examples of commensalism


  • Remora fish and shark
  • Bird's nest fern and tree
• Parasitism


  An interaction where one organism (the parasite) benefits by harming the other organism (the host)
• Examples of parasitism


  • Tapeworm and human
  • Lice and human/animal
• Prey-predator


  An interaction where one organism (the predator) eats another organism (the prey)
• Examples of prey-predator


  • Cheetah and deer
  • Bear and fish
• Competition


  An interaction where organisms compete for limited resources like food, space, mates etc.
• Examples of competition


  • Cheetah and lion competing for food
  • Zebras competing for mates
• Biological control


  Using natural predators, parasites or pathogens to reduce the number of pests in an area
• Examples of biological control

  • Owls to control rats in palm oil plantations
  • Bacillus thuringiensis bacteria to control rhinoceros beetles
  • Ladybird beetles to control aphids
  • Ducks to control snails and insects in paddy fields
• Advantages of biological control

  • Environmental friendly
  • Cheaper
  • Does not affect human health
• Disadvantages of biological control

  • Takes a long time to see effects
  • Can disturb the balance of the ecosystem
• Symbiosis


  An interaction when two or more organisms of different species live very closely together and interact with each other
• Types of symbiosis


  • Mutualism
  • Commensalism
  • Parasitism
• Mutualism


  An interaction or relationship that benefits both organisms living together
• Examples of mutualism


  • Clownfish and sea anemone
  • Fungi and algae (lichen)
  • Miner bird and buffalo
• Commensalism


  An interaction where one organism benefits while the other is neither harmed nor benefited
• Examples of commensalism


  • Remora fish and shark
  • Bird's nest fern and tree
• Parasitism


  An interaction where one organism (the parasite) benefits by harming the other organism (the host)