Span of geologic time from с 543 million years ago, the end of the Proterozoic Eon , to the present.
The Phanerozoic, the eon of visible life, is divided into three major eras: the Mesozoic , and Cenozoic . Although life originated in {{link=Precambrian time">Precambrian time , it was in the Phanerozoic that many forms arose and evolved. The Earth gradually assumed its present configuration and physical features through such processes as plate tectonics , mountain building, and glaciation.