Something Almost Entirely Killed Our Ancient Ancestors, Scientists Say


On the Ropes

Based on recent studies, it appears that our ancient ancestors faced almost complete extinction before Homo sapiens could even begin to evolve.


A study that was published in the journal Science discovered genetic evidence of an astonishing collapse of an unidentified human ancestor's population 900,000 years ago. The results indicate that, following an unexplained disaster, there may have been as few as 1,280 breeding people left, compared to a peak of 100,000 – a figure that would not rise for an additional 117,000 years.


According to Haipeng Li, a population geneticist at the University of Chinese Academy Sciences in Beijing and co-author of the study, "about 98.7 percent of human ancestors were lost," she told Nature.


According to archaeologist Nick Ashton of the British Museum, the community must have "occupied a very localised area with good social cohesion" in order for it to have survived for such a long time.


"If this is correct," he continued, "then one imagines that it would require a stable environment with sufficient resources and few stresses to the system."


Close Knit Community

For prehistoric history, the years 600,000–1,000,000 years ago were tumultuous. Droughts and little ice ages occurred periodically, and the climate was unpredictable overall. Regarding how our forefathers were born under those circumstances, many questions persist.


Still, this most recent finding offers a significant new understanding. The researchers examined 3,154 individuals' genomic data from 50 distinct populations in order to look back in time. They then created a kind of evolutionary history for those communities by comparing the emergence of distinct genomes in each community.


Their findings suggest that the pressure of evolution leading to the emergence of Homo sapiens may have come from this bottleneck. According to the researchers, forcing our ancestors to live in close quarters may have eliminated up to two-thirds of genetic variation, giving rise to characteristics unique to humans, such as a large brain.


"It was fortunate, but evolutionary biology tells us that new species can emerge in small, isolated populations," Sapienza University of Rome anthropologist Giorgio Manzi, a senior author, told TheGuardian.


But it's anyone's guess as to what created the congestion. Li speculates that abrupt changes in the climate might be to blame. London's Natural History Museum's Chris Stringer, head of human origins, isn't so sure.


"Maybe this bottleneck population was stuck in some area of Africa surrounded by desert," he told the British newspaper.

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