What Is an Ecosystem?

An ecosystem encompasses all the living (biotic) components — plants, animals, fungi, bacteria — and the non-living (abiotic) components — water, soil, sunlight, temperature, minerals — within a defined area, and the complex interactions between them. Energy flows through ecosystems primarily from the Sun through producers (plants), to consumers (herbivores, predators), to decomposers. Nutrients cycle continuously between organisms and the physical environment. Ecosystems can range from a small tide pool to the entire Amazon rainforest. They provide essential services: clean air and water, pollination, carbon sequestration, and flood control.