Final answer:
Human ancestors first migrated out of Africa around 200,000 years ago, with a major migration around 100,000 years ago. A second major wave of migration involved Homo erectus around 1.5 million years ago. Modern Homo sapiens later populated the entire globe, including the Americas.
Step-by-step explanation:
Archaeological evidence suggests that Homo sapiens began migrating out of eastern and southern Africa around 200,000 years ago, initially expanding within the continent. The first major migration out of Africa occurred approximately 100,000 years ago, marking the beginning of Homo sapiens' global migration, taking paths through Asia and eventually reaching other continents, such as Europe and Australia. The second major movement out of Africa is associated with Homo erectus, which occurred around 1.5 million years ago.
Early humans adapted to their new environments, leading to diversification within the species. These migratory patterns were influenced by various factors, including following game, seeking new food sources, and responding to climate changes such as the ice age starting around 36,000 years ago.
Theories like the "out of Africa" model indicate that modern humans spread from Africa and replaced all other human species. Despite controversies, it's broadly accepted that Homo sapiens were the first to settle the Americas, much later than their arrival in Europe and Asia, and there is no evidence of earlier hominin species in North or South America.
Significance of Early Migrations:
The early migrations of Homo sapiens and Homo erectus out of Africa represent significant events in human prehistory, shaping the genetic and cultural development of humanity across the globe. These migrations allowed humans to colonize nearly every habitable part of the planet, leading to the diverse and complex societies we see today.