Back in 1988, evolutionary biologist Richard Lenski took some E. coli bacteria and put them in a dozen glass flasks. These 12 populations of bacteria have been there ever since, eating and dividing in isolation — over and over and over again. Now, some 25 years and 50,000 generations later, the strain has demonstrated some very noticeable changes.
What he and his colleagues at Michigan State University in East Lansing discovered was that, even in the static, boring lab flask, the bacteria never stopped evolving.
On it's own this may not sound surprising. Evolutionary theory would suggest that, even in the absence of any kind of selectional pressures, genes will slowly drift and degrade over time; there's very little to reinforce the integrity of genetic traits outside of basic biological functions, like replication.