Human Evolution

Around 900,000 years ago, our early human ancestors faced a severe population bottleneck that brought them perilously close to extinction. 

Genetic studies of modern human DNA reveal that the breeding population plummeted to roughly 1,300 individuals, representing a loss of nearly 99 percent of the ancestral group. 

This drastic decline coincided with the Mid-Pleistocene Transition, a period of intense climate upheaval when Earth entered longer and harsher ice ages. 

In Africa, enhanced aridity transformed landscapes into expanding savannas and arid zones, depleting food and water resources for early Homo populations.

Faced with these dire conditions, a mass migration out of Africa became a lifeline. As global sea levels dropped due to expanding ice sheets, new land routes opened across continents, allowing hominins to disperse into Eurasia. 

Archaeological evidence shows a cluster of habitation sites in Europe and Asia dating precisely to this era, confirming the timing. 

This rapid exodus not only helped survivors escape the worst effects of climate change but also enabled adaptation to new environments, facilitating population recovery and contributing to the genetic diversity observed today. 

The migration, driven by necessity, likely prevented total extinction and paved the way for later human evolution.

Source: Proceedings of the National Academy of Sciences (PNAS), study by Muttoni and Kent.