Guppies are small fresh-water fish that biologists have studied for long. UC Riverside-led study shows wild Trinidadian guppies adapted in less than 30 generations to a new environment RIVERSIDE, Calif. – How fast can evolution take place? In just a few years, according to a new study on guppies led by UC Riverside's Swanne Gordon, a graduate student in biology. Gordon and her colleagues studied guppies — small fresh-water fish biologists have studied for long — from the Yarra River, Trinidad. They introduced the guppies into the nearby Damier River, in a section above a barrier waterfall that excluded all...