Several hundred thousand years ago human beings walked out of Africa.

What's been a subject of debate amongst anthropologists is why it happened, how it happened, and how many times it happened.

The process by which Homo sapiens left their land of origin to

populate the rest of the world has been one of the fundamental questions in

anthropology. Learn more about the Out of Africa hypothesis and the origins of

humanity on this episode of Everything Everywhere Daily. The Out of Africa Hypothesis is perhaps more accurately called the Out of Africa Hypotheses

as there are several different theories. What all the various theories are in agreement on

is that humans originated in Africa.

To understand the theories, it's helpful to understand the origin of our understanding

of early humans.

In the 19th century after Darwin wrote the origin of species we didn't have a lot of

evidence for anything about early humans one way or another. Outside of

modern humans the only fossil evidence we had was from Neanderthal or

Homo erectus skeletons.

That and comparative anatomy with other animals like chimpanzees and guerrillas was it.

Initially, it was assumed that all the early hominids that were discovered were not related to humans at all.

As you'll see, the reason why theories of early humans have changed over time

is that more and more evidence has been collected,

primarily in the discovery of fossils, but also with improved techniques.

In the 20th century, more and more hominid fossils were discovered.

In particular, Australopithecus fossils were discovered in the 20s and 30s and

Homo Heidelberginta skulls in the 1950s.

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