Extinction is the normal fate of almost every species that has ever lived — but five times in Earth's deep history, the losses spiked into catastrophe, wiping out huge fractions of all life in a geological instant. This episode explores the Big Five mass extinctions, what caused them, and the hard question of whether we're now living through a sixth.

You'll come away understanding the difference between everyday extinction and a mass extinction, what drove the great dyings of the past, why the end-Permian event nearly ended life altogether, and how scientists weigh the evidence about today.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: Natural History Museum (London) – "Mass extinctions"; Smithsonian – "The Big Fi ...