Trivial
Biology

Ecosystems

Levels of organisation and interdependence, the carbon and water cycles, and biodiversity.

9 min read

An ecosystem is organised from individuals → populations → communities → ecosystems. Communities are affected by abiotic (non-living, e.g. temperature) and biotic (living, e.g. food supply) factors, which can change population sizes. Organisms depend on each other through predation, mutualism, parasitism and competition. Photosynthetic organisms are the primary producers of food and biomass.

The carbon cycle: CO2 in the atmosphere linked by photosynthesis, respiration, feeding, combustion of fossil fuels and decomposition.
Carbon moves between the air and living things via photosynthesis, respiration, combustion and decomposition.

The carbon cycle moves carbon between the air and living things through photosynthesis (removes CO₂), respiration and combustion (return CO₂), and decomposition. The water cycle continually recycles water, which all living things need.

Quadrats and belt transects are used to estimate the distribution and abundance of organisms, and to estimate the number in an area. Human activities such as fish farming, acid rain and eutrophication can have positive or negative effects on biodiversity.

  • Confusing abiotic (non-living) with biotic (living) factors.
  • Forgetting that producers (plants) are the base of every food chain.