Humans may owe their place on the planet to a mass extinction of fish 360 million years ago, it was claimed.

The cataclysmic event reset the evolutionary starting point for all vertebrates living today, said US scientists. If it had not occurred, humans and their ancestors may not have evolved - or could have evolved very differently. Key features shared by all modern mammals, birds and reptiles - such as five-digit limbs - originated when life re-emerged after the mass extinction, the experts believe. [ INDEPENDENT UK ]