Charles Darwin embarked on a voyage in 1831 which led him to conclude that species evolve over generations from lower forms. In 1859, he published On the Origin of Species, arguing that humans and apes descended from a common ancestor. Fossil evidence shows early hominids like Australopithecus lived 4-2 million years ago in Africa with adaptations for walking upright. Homo habilis emerged around 2 million years ago, exhibiting more advanced tool-making abilities. Later Homo species migrated out of Africa and demonstrated behaviors such as controlling fire and crafting diverse stone tools.