Scientists show evolution in action in decades-long E. coli study

By Stephen Ornes

Web edition: October 12, 2012

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A decades-long experiment finds bacteria evolved over that time to eat a new food. Flasks of the germs turned cloudy when the bacteria ate this food citrate.

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E. coli bacteria live naturally in the human gut. For almost 25 years, researchers at Michigan State University have been growing the germs in 12 glass flasks. The microbes have been growing, and reproducing — and growing some more. Meanwhile, biologists have been watching, watching, watching.

Richard Lenski and his coworkers recently reported a new finding from the long-term project. In one flask, the bacteria the scientists were nurturing did something momentous: They gradually evolved, or changed. In this case, the tiny organisms developed the ability to eat a new food — but only when oxygen is around.

Visit the new Science News for Kids website and read the full story: Bacteria learn new trick