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Exploding stars could have kick-started our ancestors’ evolution

Exploding stars could have kick-started our ancestors’ evolution

New Scientist

Image: USFWS/Southeast

Was the rise of humankind written in the stars? A nearby star exploding 8 million years ago might have triggered more frequent lightning on Earth. Wildfires ignited by that lightning could help explain the rise of east African savannahs – which many researchers think provided a vital backdrop for the early evolution of hominins.

The rise of African savannahs, beginning about 8 million years ago, has long been a mystery to biologists.  They are dominated by plants called C4 grasses – but those grasses appeared 20 million years ago, long before they rose to dominance. Some botanists now wonder whether the trigger was a spate of wildfires 8 million years ago. Grasses bounce back quickly after a wildfire while trees are slower to recover, so frequent wildfires would have favoured the expansion of savannahs.

Now researchers led by Brian Thomas at Washburn University in Kansas, Georg Feulner at the Potsdam Institute for Climate Impact Research in Germany and Adrian Melott at the University of Kansas have provided a possible explanation for the surge in wildfires 8 million years ago. Read more on…