Why did humans first appear in Africa?

Our ancestors first appeared in Africa, but why there and not elsewhere?

Modern humans live all over the world and there is evidence that our ancestors Homo erectus also first appeared in Africa. So why did only the African descendants of Homo erectus give birth to modern humans?

Everyone on Earth can trace their ancestors to Africa, where Homo sapiens appeared at least 300,000 years ago.

But our Homo heidelbergensis ancestors lived across Africa, Europe and Asia, and Homo heidelbergensis, the descendants of Homo heidelbergensis, lived everywhere as well.

Heidelbergs gave rise to at least three human tribes in different places: Neanderthals in Eurasia, Denisovans in Asia, and modern humans in Africa.

So why did Heidelberg people give birth to intelligent people in Africa?

Population geneticist Brenna Henn at the University of California, USA, said that "this is an extremely difficult question" . According to her, to answer this question, we first need to consider the evolutionary process. The first evolution of intelligent people.

A study published in the journal "Nature" in 1987 found that all modern human mitochondrial DNA originated from a population in Africa 200,000 to 150,000 years ago.

However, geneticist Henn and other scientists question the idea that a single population gave rise to modern humans. When modern humans first emerged, our homo sapiens ancestors were scattered into dozens of specialized populations across Africa.

Africa is a vast continent with very diverse ecosystems, so these populations must adapt to suit the specific conditions in which they live.

In a study published in the journal "Nature" in 2023, geneticist Henn and colleagues said it was likely that at least two of these populations were the ancestors of homo sapiens.

Scientists believe that despite living separately for thousands of years, each of these populations merged with each other at some point, creating a common root population that eventually became our species. .

Scientists deduce that the ecological diversity of the African continent and the subsequent mixing of many populations caused modern humans to evolve.

Paleoanthropology professor Curtis Marean at the Institute of Human Origins, Arizona State University, USA, said that scientists are still divided on whether one population or a small number of populations created modern people.

However, he said these two hypotheses are more accepted than a newer hypothesis about the African continent.

The pan-African hypothesis states that hominins evolved at the same time across the African continent. Professor Marean said "this is not consistent with any theory of evolution". He agrees with geneticist Henn's opinion that Africa's large area may have created genetic diversity, creating conditions for modern humans to develop advanced cognition and cooperative abilities. festival.

He said that the more genetic diversity, the more likely it is to evolve good things. Although the continents of Europe and Asia combined are extremely large, the warmer climate of the African continent has created conditions for intelligent people.

Periods of harsh cold climates occurring every 100,000 years have limited the evolution of hominins in Eurasia, and African sapient humans lost very little living area during the same periods. that time. With a wider range of connections, smart people have more space to become diverse and interact with each other more, creating conditions for more gene flow.

"Studying human evolution is learning about the process by which we transformed to become what we are today. It's hard to imagine anything more important than that" - Professor Marean said.

He emphasizes that all of these observations are theoretical and that there is still much to discover, such as which population(s) evolved into modern humans and whether language played a role in the development of humans. cognitive development of modern people or not. He hopes future studies will answer these questions.