Sometimes people claim that there is little evidence of evolution that we can actually see, or that the examples are of only trivial importance. I thought the article above on the research of Regina Baucom and coauthors was a wonderful example of evolution before our eyes.
When Roundup (containing the active herbicide glyphosate) is used to kill the pretty weed morning glory, some morning glory plants have genes that help protect them and therefore survive better.
But there is more. Morning glory plants have both male and female parts: pollen-producing anthers and the pollen-receiving stigma. Some of the Roundup-resistant morning glories have anther and stigma close together so they frequently self-fertilize, while other Roundup-resistant morning glories have anther and stigma far apart, so they are less likely to self-fertilize and more likely to be fertilized by another morning glory that might not be Roundup-resistant. Because the descendants of the Roundup-resistant morning glories with anther and stigma close together are more likely to inherit the Roundup-resistant genes, they will be more common in the next generation. Because these increasingly common descendants from self-fertilization of Roundup-resistant morning glories are also likely to have genes for anther and stigma close together, the population of morning glories shifts to a higher frequency of anther and stigma close together. Thus, Roundup causes the population of morning glories to evolve toward having anther and stigma close together—a different reproductive strategy—as well as causing the population of morning glories to evolve toward Roundup-resistance.