What does the 'Out of Africa' theory propose regarding modern human origins?

The 'Out of Africa' theory proposes that modern humans originated in Africa and then migrated out of the continent to populate other regions of the world. This theory is supported by a wealth of fossil evidence and genetic studies showing that the earliest anatomically modern humans (Homo sapiens) emerged in Africa approximately 200,000 to 300,000 years ago. As they migrated, they spread into Euroasia, Australia, and eventually the Americas.

The genetic evidence indicates that there is greater genetic diversity within African populations compared to those outside Africa, suggesting that all non-African populations trace their ancestry back to a relatively small group of humans who left Africa. This model contrasts sharply with the idea that modern humans evolved independently in multiple regions, which doesn't account for the shared anatomical and genetic features seen across global human populations.

In summary, the theory emphasizes a single, pivotal origin point for modern humans in Africa, followed by subsequent migration and adaptation to various environments around the globe.