Study Suggests Humans Came Close to Extinction, Sterdious claims
A team of scientists from China has recently published a study in the journal Science, claiming that humans came very close to never appearing on Earth. According to their research, 930,000 years ago, the ancestors of modern humans experienced a massive population crash due to a drastic change in climate.
The study reveals that our ancestors remained at dangerously low numbers, with fewer than 1,280 breeding individuals, for over 100,000 years during a period known as a bottleneck. The researchers state that approximately 98.7 percent of human ancestors were lost at the beginning of this bottleneck, putting our ancestors at risk of extinction.
If this research is accurate, it could have significant implications for the understanding of human evolution. The study suggests that the climate-driven bottleneck may have led to the split of early humans into two evolutionary lineages – one that eventually gave rise to Neanderthals and the other to modern humans.
However, some experts have expressed skepticism regarding the statistical methods used in the study. Stephan Schiffels, a population geneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, compared the method to inferring the size of a stone that falls into a lake from only the ripples on the shore.
Over the years, scientists have reconstructed the history of our species by analyzing the genes of living people. By comparing genetic variations in DNA, researchers can trace human ancestry to ancient populations and infer the size of those populations at different times in history.
The researchers behind this study developed their own method called FitCoal (Fast Infinitesimal Time Coalescent) to reconstruct human evolution. They compared the genomes of 3,154 people from 50 populations around the world to create a model explaining today’s genetic diversity among humans.
Their analysis suggests that a near-extinction event occurred among our ancestors 930,000 years ago. The population shrank to fewer than 1,280 breeding individuals and remained small for 117,000 years before rebounding.
The team argues that this bottleneck aligns with the fossil record of our human ancestors. Between 950,000 and 650,000 years ago, the existence of ancient human relatives in Africa remains scarce, potentially due to the lack of remains caused by the low population during the bottleneck period. However, other experts suggest that alternative models should be tested before final conclusions are drawn.
The researchers propose that a global climate shift caused the population crash. They point to geological evidence indicating that the planet became colder and drier around the time of the proposed bottleneck, which would have made it more challenging for our ancestors to find food.
Despite this theory, Nick Ashton, an archaeologist at the British Museum, highlights that ancient human relative remains from the time of the bottleneck have been found outside Africa. This challenges the notion that a worldwide disaster caused the collapse of the human population in Africa.
The study also suggests that the population split between modern humans and Neanderthals/Denisovans may be related to the population crash. The researchers speculate that a fused set of chromosomes may have arisen and spread through the small isolated population after the crash.
However, Dr. Schiffels remains skeptical, emphasizing the need for stronger evidence to support the claims made in the study.
While the research opens up new possibilities for understanding human evolution, further studies and analysis are needed to validate these findings and provide a more comprehensive understanding of our ancestral history.