Populations, communities and ecosystems
Population: organisms of one species living in the same area at the same time, with the potential to interbreed.
Populations of several species that live and interact in the same area make up a community. When that community is considered together with the non-living environment it interacts with, it forms an ecosystem.
Ecosystems occur on very different scales, from a small pond to an ocean. Energy flows through an ecosystem, while nutrients are recycled, including through the carbon, nitrogen and phosphorus cycles.
Organisation at a glance
- Individual: one organism.
- Population: members of one species occupying an area at the same time.
- Community: interacting populations of different species.
- Ecosystem: the community interacting with its abiotic environment.