Earth as a System

Nothing influences the subsystems that contribute to Earth's dynamic behavior more than heat, which comes from two sources: solar energy and radioactivity in the Earth's core. Because of the angle at which the sun strikes Earth, Earth's surface is heated unevenly. This affects Earth's climate, which in turn, influences what types of animals and plants can survive in a particular location. The uneven heating also controls Earth's weather systems. The heat absorbed by the oceans and carried by its currents is constantly being released into the atmosphere. This heat and moisture drives atmospheric circulation and sets weather patterns in motion. The weather patterns then influence vegetation, as well as erosion and sediment transport.

The other heat source, deep within Earth's core, is responsible for plate tectonics, which gives the Earth its topography: mountain ranges and valleys, ocean basins and lake beds, and islands and trenches. The heat from Earth's core generates convection cells within its mantle, which help drive plate activity.


Source: Teachers' Domain, Earth as a System, published December 17, 2005, retrieved on December 29, 2009, http://www.teachersdomain.org/resource/ess05.sci.ess.earthsys.hologlobe/