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Productivity

IB Environmental Systems and Societies • Unit 2

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Productivity in ecosystems

Productivity describes how fast plants and other producers turn energy (mainly sunlight) into living material such as leaves, stems, and roots. In simple terms, it shows how much new life an ecosystem can support.

Most productivity comes from producers (like plants and algae) through photosynthesis, which forms the energy base for all food chains.

  • Gross productivity (GP) — all the energy captured before anything is used.
  • Net productivity (NP) — the energy left for growth, reproduction, and feeding consumers.
NP = GP − respiration

Only net productivity is available to be passed on to the next trophic level.

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