The early Earth was hot magma. Was hit by a meteorite crash all the time. Elements heavier elements such as iron and nickel sank down into the Earth's core. While the lighter elements such as silicon floating up to the surface. Very light elements and compounds such as hydrogen, carbon dioxide and water vapor from the surface, trying to insert itself into the atmosphere. When the Earth cooled crust crystallized minerals and rocks. Water vapor condensation from rain. Rain water has dissolved carbon dioxide to accumulate on the surface. Flowing into the seas and oceans Two billion years later, the evolution of life. Frozen carbon dioxide in the air to photosynthesis. Create food and energy Production and release the gas oxygen. Oxygen to float up into the upper atmosphere. Then split the single oxygen atom. And combines with the oxygen atom double the existing ozone is a gas. This helps prevent damage from ultraviolet radiation. Ever since then, making a living on the land, they have increased. Oxygen plays a significant role in changing the Earth's surface at a later time (Figure 2), ratio of living organisms such as plants and animals as a factor controlling the amount of carbon dioxide and oxygen in the atmosphere. And control greenhouse gas emissions to be in equilibrium. You can follow the evolution of the Earth by geologic history.