In “Evolution to the Rescue: Species May Adapt Quickly to Rapid Environmental Change, Yeast Study Shows” (ScienceDaily, June 23, 2011), we learn:
… according to McGill biology professor, Andrew Gonzalez, the question arises, “Can evolution happen quickly enough to help a species survive?” The answer, according to his most recent study, published in Science, is a resounding yes.
By using a long-armed robot working 24/7 over a period of several of months, McGill Professors Graham Bell and Gonzalez were able to track the fate of over 2000 populations of baker’s yeast for many generations. Yeast was chosen for the experiment because a lot is known about the genetic makeup of this model organism and because it can reproduce in a matter of hours.[ … ]
What they observed was that the likelihood of evolutionary rescue depended on the severity and rate of change of the environment and the degree of prior exposure of populations to the environmental stressor (salt). The degree of isolation from neighboring populations also affected the capacity of the yeast populations to adapt through the accumulation of beneficial mutations.
Gonzalez and his team were in effect watching evolution at work. And what they discovered is that it can happen surprisingly fast, within 50 to 100 generations.
Then the wheels fell off.
“The same general processes are occurring whether it’s yeast or mammals,” said Gonzalez. “At the end of the day we can’t do the experiment with a panda or a moose, for example, because the time it would take to study their evolution is far longer than the time we have given the current rate of environmental change. At some point we have to work at the level of a model and satisfy ourselves that the basic reality we capture is sufficient to extrapolate from.” While there has been theoretical work on the subject done in the past, this is the first time anyone has done a practical experiment of this kind, and shown evolutionary rescue at work.
This isn’t what most people mean by evolution at work, in the sense of leading to new species, and it won’t likely apply to most species. Nice try though, and interesting experiment.