Physical Geography is a sub field of geography that focuses on the systematic study of patterns and processes within the hydrosphere biosphere atomsphere and lithosphere. It aims to understand the physical layout of the earth its whether and global flora and fauna patterns. Many areas of physical geography make use of geology particularly in the study of weathering and erosion. The geology of other planets is discussed at Geological features of the solar system. Physical geography as a scientific discipline is usually contrasted with and complemented by its sister science human geography. Over geological time the earth has changed physically.
A product of these changes was the creation of conditions in which life became possible. Once established, the burgeoning life-forms which the earth supported became a part of the substantive matrix of earth evolution. Some of the latest-developed of these opportunistic life-forms were small, bipedal apes. From the forests and savannahs of Africa, some of the hominid ancestors of these apes evolved into people. As people, and like the other life-forms with which they shared the planet, they responded in different ways to the environment of which they had become a part. And out of these responses, empowered by the development of language and bonded by the crystallization of ritual into religion, their influence upon it began to enlarge. Human groups became culturally differentiated : some became sendentary as the realization of agricultural systems and incipient urbanization signalled the possibilities of societal enlargement and the extension of socio-political ambition through the control of other people and of earth space. It was some of these groups that were to be primarily responsible for 'The Great Transformation'.