• An?ecosystem?in a?particular area?includes:
  • All the?living?components (i.e.?biotic factors?such as organisms and their interactions)
  • All the?non-living?components (i.e.?abiotic factors?such as temperature and rainfall)

   

• All ecosystems include (and depend on)?primary producers
  • Primary producers are organisms that?make their own glucose
  • For example,?plants?and?algae?produce glucose via?photosynthesis
  • Even deep-sea ecosystems such as those around hydrothermal vents (where there is?no light) depend on?primary producers?(in this case bacteria) that use a process known as chemosynthesis to make glucose from the chemicals released from these vents

   

• In ecosystems where?sunlight?and?water?is available, the process of photosynthesis enables plants to?synthesise?organic compounds (glucose?and other sugars) from?carbon dioxide
  • In?terrestrial?(land-based) ecosystems, plants use CO₂?from the?atmosphere
  • In?aquatic?(water-based) ecosystems, plants use CO₂?dissolved in the water

   

• The process of photosynthesis transforms?light energy?into?chemical energy?held in biological molecules
• The chemical energy in these biological molecules can then be used by other organisms within the community known as?consumers?(i.e. the organisms in?higher trophic levels)
  • Primary consumers?(herbivores or omnivores) feed on producers
  • Secondary consumers?(carnivores or omnivores) feed on primary consumers
  • Tertiary consumers?(carnivores or omnivores) feed on secondary consumers

   

Trophic levels for a simple food chain - the blue arrows show how the chemical energy originally produced by the primary producer (grass) is transferred to other organisms in the community