Our ancestors lost nearly 99% of their population, 900,000 years ago
Sep 6, 2023
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900,000 years ago, human ancestors faced extinction with a population crash, impacting genetic diversity and driving the evolution of modern humans. Antarctica's research stations have left high levels of pollution, but the extent of the impact is unknown. Melting sea-ice around Antarctica is causing emperor penguins to abandon breeding colonies, resulting in the deaths of many chicks. AI is being trained to describe smells, with potential applications in perfumes and food products.
Around 900,000 years ago, the ancestors of modern humans faced a population crash, reducing their breeding population to just 1,280 individuals for 117,000 years, potentially driving the evolution of important features like brain size.
Poor waste practices at Antarctica's research stations have resulted in high levels of pollution, including hydrocarbons, heavy metals, and carcinogenic pollutants, with unknown long-term consequences on biodiversity.
Deep dives
Human ancestors nearly went extinct around 900,000 years ago
A recent article in Nature discusses how human ancestors in Africa were on the verge of extinction around 900,000 years ago. The research, based on a new model using genetic data from present-day humans, estimates that the population of our ancestors drastically reduced from 100,000 individuals to 1,280 breeding individuals and remained at that level for 117,000 years. The study suggests that this period of bottleneck may have played a significant role in the emergence of the last common ancestor of Denisovans, Neanderthals, and modern humans.
Antarctica's marine environments show signs of pollution
A study published in the journal Plus One reveals that marine sediment near Australia's Casey Research Station in Antarctica contains high concentrations of hydrocarbons, metals like lead, copper, and zinc, as well as carcinogenic pollutants. The research suggests that past waste disposal practices, such as dumping waste near research stations, have contributed to this pollution. While efforts are being made to develop processes for reducing the impact of research station facilities and remediate contaminated soil using bacteria, the long-term consequences on biodiversity are still unknown.
Emperor penguin populations threatened by sea ice melting
A report published in Communications Earth and Environment highlights the impact of sea ice melting on emperor penguin colonies in West Antarctica. Record low levels of sea ice in 2022 caused four colonies to abandon their breeding grounds, resulting in the loss of an entire generation of chicks. While the overall emperor penguin population is not yet critically affected, future sea ice melt poses a threat to these colonies. With trends of sea ice reduction continuing, the long-term future of these colonies remains uncertain.
Around 900,000 years ago the ancestors of modern humans were pushed to the brink of extinction, according to new research. Genetic studies suggest that the breeding population of our ancestors in Africa dropped to just 1,280 and didn’t expand again for another 117,000 years. This population crash would likely have had an impact on human genetic diversity, and may have driven the evolution of important features of modern humans, such as brain size.
3:49 The pollution legacy of Antarctica’s research stations
Poor historical waste practices have left high levels of pollution around Antartica’s research facilities. By surveying the seafloor near Australia’s Casey research station, researchers have revealed high concentrations of hydrocarbons and heavy metals.This pollution is likely to be widespread, but its impact on the continent is unknown.
Persistently low levels of sea-ice around Antarctica have caused emperor penguins to abandon their breeding colonies early, resulting in the death of large numbers of chicks. Although the affected populations only represent a small number of the total emperor penguins on the continent, it’s unclear how they’ll fare if trends in sea-ice melt continue.
Researchers have developed an artificial-intelligence that can describe how compounds smell by analysing their molecular structures. The system’s description of scents are often similar to those of trained human sniffers, and may have applications in the food and perfume industries. Currently the AI works on individual molecules, and is unable to identify the smells associated with complex combinations of molecules, something humans noses do with ease.