THE-BIOSPHERE-AND-MASS-EXTINCTIONS

The Biosphere |

The biosphere is the sum of all living matter on the Earth. Highly specialized organisms have adapted to the extreme boundaries of the uppermost atmosphere and lowermost ocean depths. The biosphere is interconnected with three other spheres of the physical environment: the lithosphere, the hydrosphere, and the atmosphere.

The lithosphere is the solid outer layer of the Earth's crust, including rocks, sand, and soil. The Earth's lithosphere is a dynamic area, with processes such as erosion, earthquakes, and plate tectonics (shown in Figure 1) constantly altering and forming/destroying the surface. The tectonic cycle describes the formation of new crust in some areas and its destruction in others.