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In his fourth-floor lab at Harvard University, Michael Desai has created hundreds of identical worlds in order to watch evolution at work. Each of his meticulously controlled environments is home to a separate strain of baker’s yeast. Every 12 hours, Desai’s robot assistants pluck out the fastest-growing yeast in each world — selecting the fittest to live on — and discard the rest. Desai then monitors the strains as they evolve over the course of 500 generations. His experiment, which other scientists say is unprecedented in scale, seeks to gain insight into a question ( http://www.simonsfoundation.org/quanta/20140717-the-new-science-of-evolutionary-forecasting/ ) that has long bedeviled biologists: If we could start the world over again, would life evolve the same way ?
Many biologists argue that it would not, that chance mutations early in the evolutionary journey of a species will profoundly influence its fate. “If you replay the tape of life, you might have one initial mutation that takes you in a totally different direction,” Desai said, paraphrasing an idea first put forth by the biologist Stephen Jay Gould in the 1980s.
Desai’s yeast cells call this belief into question. According to results published in Science in June ( http://www.ncbi.nlm.nih.gov/pubmed/24970088 ), all of Desai’s yeast varieties arrived at roughly the same evolutionary endpoint (as measured by their ability to grow under specific lab conditions) regardless of which precise genetic path each strain took. It’s as if 100 New York City taxis agreed to take separate highways in a race to the Pacific Ocean, and 50 hours later they all converged at the Santa Monica pier.
http://www.wired.com/2014/10/evolution-paths-fitness/
(Score: 3, Insightful) by Immerman on Saturday October 04 2014, @05:36PM
That assumes you start high enough on the hill that it has only a single peak above you. Try doing the same thing starting at the bottom of a mountain range and you'll find there's an awful lot of different peaks above you.
As far as the yeast in this case is concerned there's only one peak, because they are being artificially selected for only one trait (speed of reproduction), so convergent evolution is almost inevitable. Out in the real world though we have these things called "ecological niches" wherein various unrelated species are continuously influencing each other's development through competition and collaboration. Once you've got a chaotic system in play you increase the number of local maximums dramatically and convergence becomes the exception rather than th norm.