This document provides information about prehistory and the geologic timeline of Earth. It discusses the major eras - Precambrian, Paleozoic, Mesozoic, and Cenozoic - and how life evolved during each era. Key events include the emergence of oxygen-producing cyanobacteria, the five major mass extinctions, the rise and fall of the dinosaurs, and the dominance of mammals in the Cenozoic era. Interactive labs and videos are suggested to help students learn about Earth's 4.5 billion year history in an engaging way.