Alexander W. answered • 09/14/20
Biology & Ecology for Middle School, High School, and College
There are many ways to answer this question, but we can start with some definitions about the different parts of the biosphere.The lithosphere is the solid area of earth's surface, the atmosphere is the surrounding air that is above the lithosphere, and water on the surface and in the air make up the hydrosphere.
Since all of these regions contain life, they all make up the biosphere. One common theme within all the spheres is the presence of oxygen, which is required for many kinds of life. Another common source of energy for life is light, which is used by plants and algae to photosynthesize, turning water and carbon into high energy sugars. Animals can then eat plants, and when they die, their remains are used by decomposing bacteria, where carbon and nitrogen based nutrients go into the soil or the ocean. These chemicals can then be used by other life. This cycle of nutrient exchange is what keeps the biosphere stable.
Therefore, parts of the biosphere can be thought of as areas where many ecosystems interact with each other in complex food webs, exchanging chemical energy within and between the lithosphere, hydrosphere, and atmosphere.
