If Humans Evolved in Africa, How Did We End Up All Over the World? — Here’s What Scientists Discovered

The Out-of-Africa theory states that modern humans, or Homo Sapiens, originated in Africa and then spread throughout the world. This theory is widely supported across the scientific community due to fossils and genetic evidence that substantiate it.

But how exactly did we reach all continents and create civilizations in each of them? This is a question that could be answered by understanding why humans migrate. These resettlements are often imagined to be a large group of human beings going on a journey together to find a place to survive. This is not exactly right, and the migrations most likely occurred in waves and not all at once.

Early Waves Didn’t Last—Then Came the Big Push

Homo Sapiens are estimated to be around 200,000 to 300,000 years old. We originated from Africa, and needed to migrate to other places to look for food, gather other resources, and survive climate change.

Scientists believe that some humans started venturing out of Africa around 125,000 to 270,000 years ago. However, these early waves of Homo sapiens did not survive for long and were not able to leave descendants. This is most likely due to a lack of technology, cultural adaptability, lack of genetic diversity, and the existence of other hominin populations like Neanderthals and Homo Erectus.

Then came the big migration around 70,000 to 50,000 years ago, where humans that are equipped with most of the necessary innovations to survive a new environment arrived. They spread all over Europe, Asia, and eventually the Americas.

Read more: Natural History Museum

Developing Ecological Flexibility Before Migration

What Is The Out Of Africa Theory?

The early humans who ventured out of Africa failed because they were not yet capable of surviving in different types of environments. It is only later on that humans within Africa had gained this ability.

Archaeologists have found evidence supporting this theory by being able to observe human presence in deserts, forests, and highlands, from around 70,000 years ago, which is when the big migration was believed to have begun.

These findings suggest that before the large group dispersed all across the globe, early humans had developed a way to thrive in various habitats, which increased their survival rate during the migration.

Routes Taken: From Africa into Eurasia

Scientists have found out 2 main paths for humans to venture out of Africa at their current technological level, about 50,000 to 70,000 years ago. The first one is the Levantine corridor through Sinai and Israel, which offered a green and thriving land route connecting Africa and Eurasia.

Later on, when the climate allowed, humans also used the Bab-el-Mandeb strait, where they crossed short coastal passages into Arabia. Then from there, they followed multiple inland trails and water routes into South Asia, reaching Australia after a few more thousand years.

Read more: Reuters

A Central Hub Before Global Spread

There is an idea that when humans migrated out of Africa that our ancestors went directly to the different continents and settled there. However, scientists have found some evidence that they created a central hub, where some of the population stayed in modern-day Iran, southeast Iraq, and northeast Saudi Arabia, for thousands of years, before finally dispersing.

This is also the same place where researchers believed humans and Neanderthals mixed. The reason is simple, because the land was habitable and resource-filled, which makes it ideal as a habitat not only for Homo sapiens but for other hominins as well.

The Out of Africa Theory: Understanding the Evidence

Author's Final Thoughts

Humans evolved from Africa, and although some ventured out as early as 270,000 years ago, most of them failed to survive. It is only after our ancestors have developed enough resiliency, adaptability, and cultural norms that they were able to live and thrive in different environments that each continent has to offer.

Read next: New Study Reveals Humans Were “Hypercarnivores”, Ruling as Apex Predators for 2 Million Years

References & Further Reading

Hershkovitz, I., et al. (2018). The earliest modern humans outside Africa. Science. https://doi.org/10.1126/science.aap8369

Mallick, S., et al. (2016). The Simons Genome Diversity Project: 300 genomes from 142 diverse populations. Nature. https://doi.org/10.1038/nature18964

Groucutt, H. S., et al. (2018). Homo sapiens in Arabia by 85,000 years ago. Nature Ecology & Evolution. https://doi.org/10.1038/s41559-018-0518-2

Skoglund, P., & Mathieson, I. (2018). Ancient genomics of modern humans: The first decade. Annual Review of Genomics and Human Genetics. https://doi.org/10.1146/annurev-genom-083117-021749

Ragsdale, A. P., et al. (2023). A weakly structured stem for human origins in Africa. Nature. https://doi.org/10.1038/s41586-023-06055-y