From PhysOrg.com:
Two years ago, Voytek managed to develop a second, unrelated enzymatic RNA molecule that also can continuously evolve. This allowed her to set the two RNAs in evolutionary motion within the same pot, forcing them to compete for common resources, just like two species of finches on an island in the Galapagos.
In the new study, the key resource or “food” was a supply of molecules necessary for each RNA's replication. The RNAs will only replicate if they have catalyzed attachment of themselves to these food molecules. So long as the RNAs have ample food, they will replicate, and as they replicate, they will mutate. Over time, as these mutations accumulate, new forms emerge — some fitter than others.
When Voytek and Joyce pitted the two RNA molecules in a head-to-head competition for a single food source, they found that the molecules that were better adapted to use a particular food won out. The less fit RNA disappeared over time. Then they placed the two RNA molecules together in a pot with five different food sources, none of which they had encountered previously. At the beginning of the experiment each RNA could utilize all five types of food — but none of these were utilized particularly well. After hundreds of generations of evolution, however, the two molecules each became independently adapted to use a different one of the five food sources. Their preferences were mutually exclusive — each highly preferred its own food source and shunned the other molecule's food source.
In the process, the molecules evolved different evolutionary approaches to achieving their ends.
More here.