Human evolution began with early hominins like Ardipithecus and Australopithecus around 4-5 million years ago in Africa. Key early species included Australopithecus afarensis like "Lucy" dated to 3.2 million years ago. Later hominins included Homo habilis around 2.4-1.4 million years ago, known for early stone tool use, and Homo ergaster around 1.7-2.5 million years ago in Africa, likely ancestor of later humans. Homo erectus emerged around 1.8-1.3 million years ago in Africa and spread throughout the Old World.