Tallahassee -- U.S. scientists say an experiment with two populations of guppies shows that evolution's influence on ecology can be as great as the converse.
Professors Joseph Travis of Florida State University and David Reznick of the University of California-Riverside said they studied guppies who evolved to live in upstream communities of Trinidad, and genetically distinct guppies who evolved to live downstream.
The researchers said that because upstream guppies have fewer predators, they grow slowly and larger, reproduce later and less, and die older. In contrast, downstream guppies live where predators thrive, so that downstream guppies grow rapidly and smaller, reproduce quickly and die younger.