Chapter 1 - The Evolution of Earth—The Geochemical Partner of the Global Ecosystem (5 Billion Years of History)

Abstract

This chapter describes the formation of Earth and its place in our planetary system. The chapter concerns the Earth's evolving ecology, where ecology is defined by the study of the relationship between organisms and their physical and chemical surroundings. It begins with an account of geological chemistry starting from the Big Bang theory, which created the first light chemical elements—especially hydrogen and helium—from which stars were formed. The chapter also provides a brief description of the geological development of the Earth over a period of almost five billion years. The initial stages occurred at close to equilibrium giving a reduced core and a solid mantle of more oxidized chemicals. The mantle separated the core and much of itself from any of the chemicals that accumulated later on or above the surface. These chemicals were again mostly reduced, though carbon was mainly in the form of carbon dioxide and carbon monoxide. It is at this point of time that the original sea and atmosphere were formed. The role of the chemical elements, rather than particular types of compound, in evolution of the Earth's mineral surface and life are focused in the chapter. The physical nature of the Earth, geological periods, and formation of minerals are also discussed in the chapter. The chapter concludes with a discussion on the role of oxygen in the changed Earth's surface chemistry in atmosphere and water.