An ecosystem consists of all living organisms and the physical environment in which they interact. This consists of living, biotic, features such as plants, animals and other organisms; and non-living, abiotic, factors such as the landscape, temperature, humidity and weather.
The biotic and abiotic features in an ecosystem are linked together by energy flows and nutrient cycles. Energy enters the ecosystem via photosynthesis, enabling it to be used by plants.
Every factor in an ecosystem depends on every other factor, directly or indirectly. For example, a change in temperature may change the plants that grow there, or may affect their location or the times they grow at. Animals that depend on these plants for food and shelter will have to adapt to the change, move to another ecosystem, or perish.
Ecosystems can vary widely in size. Tide pools, for example, are complete ecosystems on a very small scale. Earth’s surface is a series of connected ecosystems. Ecosystems are often connected by a larger biome. Biomes are large sections of land, sea or atmosphere. Forests, ponds, reefs and tundra are all types of biomes and are organised by the types of plants and animals within them. A variety of different ecosystems can be found within each individual biome.