Energy Flow

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•  Chemical energy in carbon compounds flows through food chains by means of feeding

Energy enters most ecosystems as sunlight, where it is converted into chemical energy by producers (via photosynthesis)

  • This chemical energy is stored in carbon compounds (organic molecules) and is transferred to heterotrophs via feeding

Trophic Levels

The position an organism occupies within a feeding sequence is known as a trophic level

  • Producers always occupy the first trophic level in a feeding sequence
  • Primary consumers feed on producers and hence occupy the second trophic level
  • Further consumers (e.g. secondary, tertiary, etc.) may occupy subsequent trophic levels

The trophic levels in a community are:

trophic level

Food Chains

A food chain shows the linear feeding relationships between species in a community

  • Arrows represent the transfer of energy and matter as one organism is eaten by another (arrows point in direction of energy flow)
  • The first organism in a food chain is always a producer, followed by consumers (primary, secondary, tertiary, etc.)

Examples of Food Chains in Different Habitats

          Term:             Grassland Food Chain                    Marine Food Chain                     Pond Food Chain