On Start the Week Tom Sutcliffe explores life in the oceans. The biologist Luke Rendell studies the evolution of social learning in whales and dolphins, and seeks to define their culture beneath the waves. The seahorse is a creature with a rich mythical history and is the subject of Andrew Motion's latest poem, while the biologist Helen Scales weaves science, natural history and culture in her story of the seashell. The biochemist Nick Lane looks back over 4 billion years to explain why life is the way it is and believes energy flux is the vital factor that has driven the origin and evolution of life. Producer: Katy Hickman.