For the first time, scientists at Exeter University have captured on film the process by which plants alert each other to possible dangers.

When a plant is under attack it releases a gas which warns neighbouring plants to protect themselves.

In a new BBC Two series, Professor Iain Stewart explains how the Earth's development was driven by plants and how they have adapted for survival.

How To Grow A Planet is broadcast on BBC Two at 21:00 GMT on Tuesdays 7,14 and 21 February or catch up via BBC iPlayer.