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Biology 0610

19. Organisms and their environment

Energy flow, food chains and webs, and nutrient cycles.

  1. 19.1

    Food chains, food webs and energy flow

    How energy moves through an ecosystem, and why it runs out.

    Full lesson2 questions5 cards
    • 19.1.1Describe food chains and webs and the terms producer, consumer, herbivore, carnivore and decomposer.
    • 19.1.2Explain energy loss between trophic levels and the shape of pyramids of biomass.
  2. 19.2

    The carbon and nitrogen cycles

    How carbon and nitrogen are recycled through ecosystems.

    Full lesson1 questions6 cardsReview first: 19.1
    • 19.2.1Describe the carbon cycle and the role of decomposers.
    • 19.2.2Describe the nitrogen cycle and the roles of the bacteria involved.
  3. 19.3

    Populations and population growth

    The phases of a population growth curve and what limits size.

    Full lesson1 questions6 cardsReview first: 19.1
    • 19.3.1Describe the phases of a population growth curve and the factors affecting population size.