Plate tectonics is a theory that explains how internal forces and energy cause continual changes within Earth and on its surface. Weathering, erosion, and deposition continuously reshape the surface of the Earth. The presence of life affects the characteristics of other systems. Earth's cycles and natural processes take place over time intervals ranging from fractions of seconds to billions of years. Materials making up planet Earth have been recycled many times.
Fossils provide the evidence that life has evolved interactively with Earth through geologic time.
Evolution is a theory that explains how life has changed through time. All material in the universe, including living organisms, appears to be composed of the same elements and to behave according to the same physical principles. All bodies in space, including Earth, are influenced by forces acting throughout the Solar System and the universe. Nine planets, including Earth, revolve around the sun in nearly circular orbits. Earth is a small planet, third from the Sun in the only system of planets definitely known to exist.