From micro- organisms inhabiting acidic springs to bears foraging in alpine meadows to people cultivating arid valleys, all forms of life within Greater Yellowstone are inextricably linked. Pull a string on one end of that web and you will find it attached to everything else. The park is also a refuge for hundreds of wildlife species, including rare trumpeter swans, our largest herds of elk, and free-roaming bison, wolves, and grizzly bears. Together they constitute one of the earth's most diverse and dynamic natural regions. Modern science has established that an ecosystem is a dynamic collection of plants, animals, and their physical environment interacting through a variety of processes and operating as a unit.
Plants grow by drawing energy from the sun and nutrients from soils and decaying matter.
Animals eat plants and each other. When animals die, their decomposing carcasses cycle nutrients back into the system. An ecosystem is self-sustaining, consuming and producing both organic materials and energy. An ecosystem can be as small as a pond or as large as the planet. The 18-million acre Greater Yellowstone Ecosystem is one of the largest, relatively intact temperate zone ecosystems left on Earth.