Primary Producers (AQA A Level Biology): Revision Note

Synthesis of organic compounds in ecosystems

• Living organisms need a supply of organic compounds in order to respire and build their tissues, e.g.:

  • carbohydrates

  • proteins

  • lipids

• In ecosystems, organic compounds are synthesised by plants during photosynthesis

• Plants use the carbon present in carbon dioxide to produce organic molecules

  • In terrestrial ecosystems plants use CO₂ from the atmosphere

  • In aquatic ecosystems plants use dissolved CO₂

• Plants are described as the primary producers in an ecosystem because they produce their own organic molecules

• The organic compounds produced by plants are passed to other organisms in an ecosystem when herbivores consume plant tissue