Microbial experiments on adaptive landscapes

The adaptive landscape is one of the most widely used metaphors in evolutionary biology. It is created by plot-ting fitness against phenotypes or genotypes in a given environment. The shape of the landscape is crucial in predicting the outcome of evolution: whether evolution will result inpopulations reachingpredictable endpoints, or whether multiple evolutionary outcomes are more likely. In a more applied sense, the landscape will deter-mine whether organisms will evolve to lose ‘costly ’ resis-tance to antibiotics, herbicides or pesticideswhen the use of the control agent is stopped. Laboratory populations of microbes allow evolution to be observed in real time and, as such, provide key insights into the topologyof adaptive landscapes. BioEssays 27:1167–1173, 2005. 2005 Wiley Periodicals, Inc