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