• Species?do not exist by themselves in their own isolated environment, they interact with other species forming?communities
• A community can be defined as:

Multiple populations (of different species) living and interacting in the same area

• For example, a garden pond?community?is made up of populations of frogs, newts, pond snails, damselflies and dragonflies and their larvea, water beetles, water boatmen, pond skaters and many other species all living and interacting within the pond habitat

Ecosystems

• Communities interact with the?non-living components?of the?environment?they live in, forming?ecosystems
• An ecosystem can be defined as:

The interaction between a community (the living, biotic part) and the non-living (abiotic) parts of the environment

• An ecosystem?is a?relatively self-contained?community of interacting organisms and the environment they live in, and interact with
• There is a?flow of energy?within an ecosystem and the?nutrients?within it are?recycled?(e.g. the carbon, nitrogen and phosphorus cycles)
• There are both?living?(biotic) components and?non-living?(abiotic) components within an ecosystem
• Ecosystems?vary greatly in size and scale
  • Both a small pond in a back garden and the open ocean could be described as ecosystems
  • A human being could also be described as an ecosystem (there are thousands of species of bacteria living on and in every person)

   

• Ecosystems?vary in complexity:
  • A desert is a relatively simple ecosystem
  • A tropical rainforest is a very complex ecosystem

   

• No ecosystem is?completely?self-contained as organisms from one ecosystem are often linked to organisms from another
  • For example, many birds species are able to migrate long distances to find food sources or breeding locations from various ecosystems

   

Example of an ecosystem

• A forest is a perfect example of a complex ecosystem
• There is a large community of organisms including trees, birds, small and large mammals, insects and fungi
• The non-living components of the ecosystem include the soil, dead leaves, water from the rain and streams, the rocks and any other physical or chemical factors
• The?non-living components?of the ecosystem?influence?the?community?of organisms

Levels of organisation in an ecosystem