EcosystemsOn this website you can explore the ways living things interact with the environment. An ecosystem is an environmental community functioning as a unit. The Earth is one large ecosystem. Another ecosystem can be as small as a pond or as large as the world's oceans. Different ecosystems are usually divided by landforms such as rivers, deserts, or mountains. In an ecosystem, all the parts work together: Atmosphere, light, heat, water, and living organisms. Subjects discussed on this page include: Water Everywhere, Getting Some Sun, Give Me a Little Air, Life in a Lake, Getting Down and Dirty, and The More the Merrier.