An ecosystem is all the living organisms in a particular area, interacting with each other and with the non-living (physical and chemical) parts of their environment. It includes the biotic (living) and abiotic (non-living) components.Some key terms:
• Habitat: the place where an organism lives.
• Population: all the individuals of one species living in the same area at the same time.
• Community: all the populations of different species living in the same area at the same time.
• Niche: the role of a species in its ecosystem, including what it eats, where it lives and how it interacts with other organisms and the environment.Ecosystems can be any size. OCR uses examples on very different scales:
• a rock pool on a shore, with seaweeds, anemones, crabs and small fish, and conditions that change as the tide goes in and out;
• a playing field, with grasses, clover, earthworms, insects and the birds that feed on them;
• a large tree, which supports lichens, mosses, insects, birds and fungi.Ecosystems are dynamic: they are constantly changing. Population sizes rise and fall, organisms move in and out, and conditions such as temperature and light vary daily and seasonally.Two processes link all ecosystems. Energy flows through them, entering as light captured by producers and leaving as heat. Nutrients such as carbon and nitrogen are recycled within them. The following lessons look at the factors that affect ecosystems, and at these flows and cycles.
• Habitat: the place where an organism lives.
• Population: all the individuals of one species living in the same area at the same time.
• Community: all the populations of different species living in the same area at the same time.
• Niche: the role of a species in its ecosystem, including what it eats, where it lives and how it interacts with other organisms and the environment.Ecosystems can be any size. OCR uses examples on very different scales:
• a rock pool on a shore, with seaweeds, anemones, crabs and small fish, and conditions that change as the tide goes in and out;
• a playing field, with grasses, clover, earthworms, insects and the birds that feed on them;
• a large tree, which supports lichens, mosses, insects, birds and fungi.Ecosystems are dynamic: they are constantly changing. Population sizes rise and fall, organisms move in and out, and conditions such as temperature and light vary daily and seasonally.Two processes link all ecosystems. Energy flows through them, entering as light captured by producers and leaving as heat. Nutrients such as carbon and nitrogen are recycled within them. The following lessons look at the factors that affect ecosystems, and at these flows and cycles.