Alex Rogers has spent the past 30 years studying marine life, and is a consultant on the BBC series Blue Planet. Here, he shares his discoveries – underwater mountains, coral reefs and strange creatures – and explains the workings of this complex ecosystem, which contains 90 percent of the Earth’s life-forms. He goes on to warn of the threat it faces from overfishing, pollution and climate change, and suggests ways in which we can protect it.

Biologists have long observed the phenomenon of ‘convergence’, by which the same adaptations (such as eyes and wings) have evolved independently in different species. But is it inevitable that natural selection will produce these same outcomes, or do tiny, random changes make evolution less predictable? Losos describes the experiments, involving life-forms ranging from bacteria to lizards and foxes, by which he and his colleagues are beginning to resolve one of modern science’s great debates. Slightly off-mint and felt-tip mark on lower trimmed edge