For Lenski and his research team, the tubes full of 12-year old, microscopic bacteria mean a world of evolutionary possibilities and answers waiting to be discovered.

Since 1988, Lenski and a growing team of researchers have fed 12 identical populations of E. coli bacteria each day and observed their real-time evolution. Lenski’s work provides evidence against a long-standing creationist argument.

Bacteria can multiply and produce a new generation in as little as 20 minutes — as opposed to humans’, which can take 20 years. This fact allowed Lenski’s team to examine evolution during a short period, but one long enough to notice significant changes.

“Over the course of the experiment, each population has evolved for more than 56,000 generations,” said Dr. Zachary Blount, a postdoctoral researcher in MSU’s BEACON Center for the Study of Evolution in Action and Lenski laboratory associate. “The experiment therefore gives us a chance to examine many aspects of evolution that are hard to study in the natural world.”

Blount and Lenski fed E. coli samples a daily solution of glucose, or sugar, and citrate, a component of citric acid that makes fruits, such as lemons, sour. Usually, E. coli is unable to grow on citrate when oxygen is present.

“After 31,000 generations of evolution, bacteria evolved … that could grow on the citrate when oxygen was present,” Blount said. “We call this new ability Cit , and it allowed the … population to get much larger.”

Although Lenski, Blount and their colleagues now are focusing on determining whether Cit bacteria is a new species, examining its range of genes and other aspects, some students are processing the discovery in other ways.

“Evolution on a small scale does occur, and the effects are apparent,” said Grant Finlayson, a human biology senior. “Antibiotics used to be effective on certain bacterial strains … now there are resistant strains of MRSA and staphylococcus.”

Finlayson said Lenski’s work could lead to changes in how antibiotics are administered.

“I don’t think it’ll affect (MSU Waters Laboratory’s) research at all because it’s ubiquitous that evolution is what it is in the scientific community,” said Joshua Smith, biochemistry and molecular biology senior, and researcher at the Waters Laboratory. “The creation argument is just … unfounded because they don’t have the resources and the scientific knowledge to really understand the process.”

Blount said the E. coli’s evolution required so many mutations that, that itself, was important.
“Creationists have argued that evolution can’t work because … changes involving more than two mutations are impossible,” Blount said. “Here, we have concrete evidence of a pretty major change that required far more than two mutations.”