New species evolve faster as mountains form
Mountains, like rainforests, are hotbeds of biodiversity. But scientists aren't sure why. For years, they've thought that it might be related to the new environments that arise when mountains form— as plants and animals adapt to the new micro-habitats and their populations become isolated by increasingly rugged terrain, they divide into new species at a faster rate than usual. However, there was little hard proof that this hypothesis was correct. In a new paper in PNAS, a team has put forth compelling quantitative evidence in favor of the hypothesis, analyzing thousands of plant species from China's Hengduan Mountains and adjacent regions. They found that as the Hengduan Mountains were forming, the plants there evolved into new species at a faster rate than in the nearby Himalayas, which are older.