This document provides an overview of the timeline of life on Earth based on emerging geological and biological evidence. It begins with the earliest geological record of the Earth around 4.6 billion years ago when conditions were violent and chaotic without oxygen in the atmosphere. The first evidence of life appears around 3.5 billion years ago in the form of prokaryotic organisms like bacteria. Around 3 billion years ago, the first photosynthetic cyanobacteria produced oxygen. Eukaryotic, multicellular organisms emerged around 2 billion years ago. The document then outlines the major eras in the timeline of life on Earth from the Paleozoic through the Cenozoic, when humans evolved. It also summarizes theories on the origin