Human

## Evolutionary Timeline of Humans The evolutionary history of humans spans millions of years, marked by major transitions from arboreal ancestors to modern Homo sapiens. Key pressures included climate-driven habitat changes, such as the expansion of savannas, which favored bipedalism, tool use, and larger brains. Important ancestors include early hominins adapting to diverse environments. ### Key Milestones - **~7-6 million years ago (Mya)**: Divergence from chimpanzee lineage; Sahelanthropus tchadensis, possible earliest hominin, in forested African environments. - **~4-2 Mya**: Australopithecus species (e.g., A. afarensis like 'Lucy') develop bipedalism amid drying climates and grassland expansion. - **~2.5-1.8 Mya**: Homo habilis emerges with stone tools, responding to variable climates and increased scavenging. - **~1.8 Mya - 200,000 years ago**: Homo erectus spreads out of Africa, adapts to diverse environments with fire use and advanced tools. - **~300,000 years ago - Present**: Homo sapiens evolves in Africa, migrates globally, influenced by ice ages; cultural evolution accelerates with language and art.