The Impact of Population Loss on Human Evolution and the Role of Climate Change

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This chapter explores the consequences of a significant population reduction of human ancestors around 900,000 years ago, including genetic changes and the emergence of the last common ancestor of Denisovans, Neanderthals, and modern humans, potentially caused by climate change.

In this episode:

00:30 Early humans pushed to brink of extinction

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.

Nature News: Human ancestors nearly went extinct 900,000 years ago

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.

Nature News: Antarctic research stations have polluted a pristine wilderness

07:43 Melting sea-ice causes catastrophic penguin breeding failure

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.

Science: Emperor penguins abandon breeding grounds as ice melts around them

09:23 The AI trained to describe smells

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.

Nature: AI predicts chemicals’ smells from their structures

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