Tectonic cycle

It involves creation and destruction of solid outer layer of Earth, lithosphere. Lithosphere is broken down into several large segments called plates, which are moving relative to one another. The force originating deep within the interior of the Earth causes movement of the rigid plates, called tectonic plates (about 100 km thick). Plate tectonics has important environmental effects of two kinds: physical and chemical.

Physical effects:  Tectonic movement causes changes in location and sizes of the continents that alter atmospheric and oceanic circulation thereby altering climate. Also movement of continents led to the breakup of continental areas creating ecological islands. Because of this breakup closely related life forms are isolated for millions of years leading to evolution of new species. This way plate tectonics greatly affect life.

Chemical effects: As the plates collide, materials they are made of are subjected to heat and pressure, and are altered in chemical form. Materials like sea shells are buried, converted to limestone (sedimentary rock), and vegetation converted to coal or natural gas.

Boundaries between plates are geologically active areas — most volcanic activity and earthquakes occur there.

 Internal structure of Earth