What is an ecosystem?

An ecosystem is a natural environment and includes the flora (plants) and fauna (animals) that live and interact within that environment. Flora, fauna and bacteria are the biotic or living components of the ecosystem. Ecosystems are dependent on the following abiotic or non-living components:

  • climate - the temperature and amount of rainfall are very important in determining which species can survive in the ecosystem
  • soil - the soil type is important as this provides nutrients that will support different plants
  • water - the amount of water available in an ecosystem will determine which plants and animals can be supported

The biotic parts of the ecosystem, which include bacteria, flora and fauna, have a complex relationship with the abiotic components - changing one will lead to a change in the other.

Energy flows

Energy flows through an ecosystem in a number of food chains. Plants act as producers at the start of all food chains, making food from the process of photosynthesis. Herbivores then eat the plants - these are the first consumers. Herbivores are then eaten by carnivores - the second consumers.

The food chain from bottom to top: Leaves and algae, Caddis, Fish, Kingfisher.

Food chains inter connect in an ecosystem to form a complex food web.

Bottom layer: detritus, algae. Layer 2: midge larva, blackfly, mayfly, aquatic worms. Layer 3: great diving beetle, stonefly, caddis, dragonfly. Layer 4: fish. Top layer: heron, kingfisher.

Nutrient cycles move valuable minerals like nitrogen, magnesium, calcium, phosphorous, and potassium through the ecosystem. Decomposers such as small bacteria and fungi break down dead vegetation and animals and return nutrients to the soil.

Bacteria decomposes material in soil to create nutrients, which plants take in. Plants can be eaten by animals. Waste from dead plants and animals are added to the soil.