A+ A A-

In this unit, students will understand the meanings of the terms habitat, population, community and ecosystem. With this knowledge, they will be able to discuss how energy is loss at each trophic level in a food chain. Students will draw food chains and food webs using terms like producers, consumers and decomposers. Knowledge of the carbon cycle will enable students to be able to describe the effect of burning fossil fuels leading to high carbon dioxide level and thus creating global warming.

Learning targets

Relationships of organisms with one another and with their environment

Energy flow

  • State that the Sun is the principal source of energy input to biological systems
  • Describe the non-cyclical nature of energy flow

Food chains and food webs (emphasis on examples occurring locally)

  • Define the terms:
      • food chain as a chart showing the flow of energy (food) from one organism to the next beginning with a producer (e.g. mahogany tree ? caterpillar ? song bird ? hawk)


    Discuss our place in the food web and or actions as Global Citizens.

    • food web as a network of interconnected food chains showing the energy flow through part of an ecosystem
    • producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
    • consumer as an organism that gets its energy by feeding on other organisms
    • herbivore as an animal that gets its energy by eating plants
    • carnivore as an animal that gets its energy by eating other animals
    • decomposer as an organism that gets its energy from dead or waste organic matter
    • ecosystem as a unit containing all of the organisms and their environment, interacting together, in a given area e.g. decomposing log or a lake
    • trophic level as the position of an organism in a food chain, food web or pyramid of biomass, numbers or energy
  • Describe energy losses between trophic levels
  • Draw, describe and interpret pyramids of biomass and numbers
  • Explain why food chains usually have fewer than five trophic levels
  • Explain why there is an increased efficiency in supplying green plants as human food and that there is a relative inefficiency, in terms of energy loss, in feeding crop plants to animals

Nutrient cycles Core

  • Describe the carbon and the water cycles
  • Describe the nitrogen cycle in terms of:
    • the role of microorganisms in providing usable nitrogen-containing substances by decomposition and by nitrogen fixation in roots
    • the absorption of these substances by plants and their conversion to protein
    • followed by passage through food chains, death, decay
    • nitrification and denitrification and the return of nitrogen to the soil or the atmosphere (names of individual bacteria are not required)
  • Discuss the effects of the combustion of fossil fuels and the cutting down of forests on the oxygen and carbon dioxide concentrations in the atmosphere

Population size


Discuss the notion of population in relation to being a Global Citizen.

  • Define population as a group of organisms of one species, living in the same area at the same time
  • State the factors affecting the rate of population growth for a population of an organism (limited to food supply, predation and disease), and describe their importance
  • Identify the lag, exponential (log), stationary and death phases in the sigmoid population growth curve for a population growing in an environment with limited resources
  • Describe the increase in human population size and its social implications
  • Interpret graphs and diagrams of human population growth
  • Explain the factors that lead to the lag phase, exponential (log) phase and stationary phase in the sigmoid curve of population growth making reference, where appropriate, to the role of limiting factors.

Presentation media

Labs and activities

Main Menu


Find Us

Saint Maur International School Science Center

83 Yamate-cho, Naka-Ku Yokohama
Kanagawa (Greater Tokyo)
JAPAN 231-8654
Tel +81-45-641-5751 | Fax +81-45-641-6688

Connect with Us