The biosphere includes everything living on Earth. Currently the biosphere has a biomass (or amount of living things) at around 1900 gigatonnes of carbon. It is not certain exactly how thick the biosphere is, though scientists predict that it is around 12,500 meters. The biosphere extends to the upper areas of the atmosphere, including birds and insects.
In a general sense, biospheres are any closed, self-regulating systems containing ecosystems. This includes artificial biospheres such as Biosphere 2 and BIOS-3, and potentially ones on other planets or moons.