The Pleistocene population bottleneck was a period in human evolution when the population of our species was reduced to a very small number of individuals. This bottleneck occurred around 930,000 to 813,000 years ago, during a time of significant climate change. The bottleneck had a profound impact on human evolution, shaping our genetic diversity, our vulnerability to diseases, and our ability to adapt to new environments.

The Pleistocene population bottleneck is thought to have been caused by a combination of factors, including climate change, volcanic eruptions, and disease. The climate at the time was becoming cooler and drier, which would have made it difficult for early humans to find food and water. Volcanic eruptions would have also caused widespread damage to the environment, making it even more difficult for humans to survive. Disease could have also played a role, as it could have spread more easily through a small population.

The bottleneck had a significant impact on human genetic diversity. When a population is reduced to a small number of individuals, the gene pool becomes smaller and less diverse. This means that the population is more vulnerable to diseases and other challenges.

The bottleneck also had an impact on human evolution. It is thought that the bottleneck may have accelerated the evolution of certain traits, such as intelligence and adaptability. This is because the small population was under selective pressure to evolve traits that would help them to survive and reproduce.

The bottleneck also had an impact on our ability to adapt to new environments. The small population was more likely to be isolated from other populations, which would have made it more difficult for them to adapt to new environments. This is thought to be one of the reasons why humans took so long to spread out of Africa.