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Energy in ecosystem new

Energy in ecosystem new






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    Energy in ecosystem new Energy in ecosystem new Presentation Transcript

    • Food Chain and Energy Transfer
    • Food Chain Producers Primary Consumers Secondary Consumers Tertiary Consumers
    • Terminology - Ecosystem
      • Herbivore
        • animals that eat only plants.
      • Carnivore
        • animals that eat only animals.
      • Omnivore
        • animals that eat plants and animals.
      • Top Carnivore
        • animals not eaten by anything else.
      • Decomposer
        • organisms that live on dead material.
      • Trophic Levels
        • each step along a food chain.
    • Primary Production
    • Primary production
      • Primary production
        • is the production of organic compounds from atmospheric or aquatic carbon dioxide, mainly through the process of photosynthesis.
      • Gross primary production
        • is the total amount of energy fixed by primary producers in an ecosystem.
      • Net primary production.
        • Some fraction of this fixed energy is used by primary producers for cellular respiration and maintenance of existing tissues.
        • The remaining fixed energy is referred to as net primary production.
    • Primary production
    • Energy Flow
      • Plants convert a small portion of light energy into glucose (biomass)
      • The energy works its way through the food chain.
      • Energy transferred from one trophic level to the next is about 10%.
      • This means that at each step in the food chain, as much as 90% of energy is lost.
    • Energy Flow
    • Energy Flow
      • Energy flows in one direction.
      • Light energy is transferred into chemical energy through photosynthesis by autotrophic organisms.
      • Autotrophs spend some energy to respire and to perform other biological activities.
      • The remaining energy is available to heterotrophs at the next trophic level.
    • Energy Flow
      • Every time there is an exchange of energy between one trophic level and another, there is a quite a significant loss.
      • This means so many units of grass can only support a much smaller number of units of rabbits, who can only support a smaller group of jackals, who can only support a smaller group of predatory birds.
      • This is why trophic levels are usually portrayed as a pyramid, one that places plants at the bottom and top carnivores at top.
      • The top is always much smaller than the bottom.
      • Each level implies a loss of energy.
      • 1. The figure below shows part of a food web in Isle Royale National Park. The number of trophic levels shown in this web is _______.
      • 1
      • 2
      • 3
      • 4
      • 5
      • Primary producers get their energy directly from the sun.
      • The greatest amount of energy loss is through respiration.
      • Detritivores receive energy from all other organisms in an ecosystem.
      • Secondary carnivores receive a large proportion of the energy produced by photosynthesis.
      • Herbivores receive energy from primary producers
      2. Flow of energy through different organisms in an ecosystem varies widely (below). Which of the following statements regarding energy flow through ecosystems is false?
      • 3. As the number of individuals of the predatory species increases, the prey population
      • increases
      • Decreases
      • Stabilizes
      • first increases, and then begins to decrease