A clear signal of urbanisation has been identified in the evolution of organisms, which has implications for sustainability and human well-being.<br/><br/>In analysis of more than 1,600 cases around the globe, researchers said the changes could affect ecosystem services important to humans. More than half of the world's human populations now live in urban areas, and this proportion is set to grow.<br/><br/>The findings appear in the Proceedings of the National Academy of Sciences.