50,000 generation experiment proves ‘adaptive evolution’ is relentless

In 1988, when evolutionary biologist Richard Lenski was an assistant professor at the University of California, Irvine, he started a simple experiment: toss E. coli into a new environment and watch what happens. He wanted to know how reproducible evolution would be, so he put the same strain of the bacteria into 12 flasks with the same simple medium and waited to see how they would evolve. E. coli normally lives in the guts of animals, so the experiment would allow for a way to observe adaptations to a new environment.

After about a year and 2,000 E. coli generations, Lenski and his colleagues published the first results of what they then considered to be a long-term experiment in evolution. Little did they know that 25 years and 50,000 generations later, the experiment would still be chugging along—those 12 flasks representing alternate universes of bacterial existence. “I guess I didn’t view it as [being as] open-ended as it clearly has become, not only as an experiment but in terms of the ability of the organisms to keep improving,” says Lenski.

The finding contradicts the “naive” view that an organism will cease getting fitter once it’s well adapted to an environment.

Read full original article: Self-Improvement Through the Ages

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