What does the "out of Africa" theory propose?

The "out of Africa" theory proposes that modern humans, Homo sapiens, originated in Africa and then migrated out of the continent to populate the rest of the world. This model is supported by genetic, archaeological, and fossil evidence suggesting that all modern human populations today can trace their ancestry back to African populations.

This theory highlights that the initial emergence of anatomically modern humans occurred in Africa, indicating a single origin point for the species. As modern humans dispersed from Africa, they migrated into Europe, Asia, Australia, and the Americas, leading to the global distribution of humans we see today.

Support for the "out of Africa" theory includes findings of the earliest fossils of modern humans in Africa and studies of genetic diversity, which show that African populations generally possess greater genetic variation than those from other continents. This reflects longstanding human presence in Africa as opposed to more recent colonization of other regions.

The other propositions suggest alternative scenarios, such as multiple independent origins or simultaneous diversification, but the prevailing evidence aligns more closely with the single-origin hypothesis put forth by the "out of Africa" theory.