An ecosystem has two basic components: A. Abiotic (non living) B. Biotic (living organism). Any planet, moon or asteroid without life is NOT an example of an ecosystem. Stars are NOT examples of ecosystems. Molten lava in a volcanic caldera is NOT an example of an ecosystem. The inside of a nuclear reactor vessel is NOT an example of an ecosystem. You can not separate a living organism from abiotic environmental factors, even if that organism is an internal parasite. Atmospheric gases, water, light and temperature are examples of necessary abiotic factors in the life of any organism. There are man-made or artificial ecosystems, such as Biosphere 2. There are agricultural ecosystems and urban ecosystems. Anything with life is part of an ecosystem.