Plot: In this years Royal Institution Christmas Lectures ecologist Professor Sue Hartley - only the fourth woman to present the lectures since they began in 1825 - shows how the epic 300-million-year war between plants and animals has shaped us and the world we live in. Plants may seem harmless, but Professor Hartley reveals that the opposite is the case: they've had to develop terrifying and devious ways to defend themselves and attack their plant and animal enemies