Why is Africa considered the cradle of humanity? This question has intrigued scientists and curious minds for decades. Throughout the ages, several hominin species roamed this vast land, but only
Homo sapiens originated there. Let's explore why.
The path of human evolution is complex. Our ancestor
Homo erectus lived in Africa, Europe, and Asia. Its descendant,
Homo heidelbergensis, gave rise to at least three species: Neanderthals in Eurasia, Denisovans in Asia, and modern humans in Africa.
Brenna Henn, a population geneticist at the University of California, Davis, emphasizes that understanding why
H. sapiens emerged in Africa requires examining the evolutionary process of the species. In 1987, a study in
Nature traced modern human mitochondrial DNA to an African population that lived between 200,000 and 150,000 years ago.
However, Henn and other scientists dispute the idea of a single origin. Our ancestors were dispersed in several specialized populations across Africa, a continent with diverse ecosystems necessitating specific adaptations.
In 2023, a study led by Brenna Henn, published in
Nature, proposed that two of these populations contributed to the emergence of
H. sapiens. These groups eventually intermingled, forming a common ancestral population.
Africa's ecological diversity and the interactions between populations likely facilitated the evolution of modern humanity. According to Henn, this genetic and behavioral diversity allowed for the development of a complex set of traits characterizing
Homo sapiens.
Curtis Marean, a professor of paleoanthropology at Arizona State University, notes that the scientific community still debates the precise origins of modern humanity. However, he concurs with Brenna Henn on the importance of Africa's size and diversity, highlighting that glacial periods in Eurasia restricted hominins, unlike the more interconnected African populations.
Marean stresses the theoretical nature of these hypotheses and the need for future research to answer key questions such as the role of language in human cognitive development.