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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: 4, Interesting) by bzipitidoo on Saturday October 04 2014, @01:29PM
The analogy of a drive to anywhere on the Pacific coast isn't the best. A better analogy is hill climbing. Life is trying to optimize, that's the idea of survival of the fittest. Start anywhere on the same hill and "hill climb". You don't have to know which way to go, all you have to do is move higher. Everyone will arrive at the same top, even if they wander a little and don't take the most direct route, find the steepest climb. It's a common operation in computational geometry. Compute the gradient, then step upwards-- or downwards if you're looking for a minimum instead of a maximum.
Sounds more likely that the experiment as performed explored a small area that didn't have more than one hill.
(Score: 0) by Anonymous Coward on Saturday October 04 2014, @01:36PM
If this is true, then why has most of Africa always been stuck in a valley, even before Europeans ever visited? Why have people in pretty much every other area of the world, from ancient Mesopotamia to ancient Mesoamerica to ancient China through to modern Europe, Japan and North America, been able to achieve civilization at some point, while all of Africa aside from ancient Egypt has not managed this?
(Score: 0) by Anonymous Coward on Saturday October 04 2014, @02:00PM
One possible reason could be conservatism. No, not political, but "This is how we've always done things!" traditionalism and similar. Just as cities built today will be superior to towns built 200 years ago, and the towns from 200 years ago are basically still exactly the same now as they were then; so long as the elders of the African Tribes were still alive, holding on to the old traditions, there would be significant resistance to change things, such as switching the tribes from nomadic to sedentary lifestyles.
(Score: 2, Interesting) by UncleSlacky on Saturday October 04 2014, @05:23PM
Clearly you've never heard of Great Zimbabwe:
https://en.wikipedia.org/wiki/Great_Zimbabwe [wikipedia.org]
(Score: 0) by Anonymous Coward on Saturday October 04 2014, @07:18PM
It's not really worthy of consideration. In fact, it actually supports what the GP was saying. Great Zimbabwe is not at all remarkable. It's pretty basic brickwork by any standard, especially for being built between 1000 A.D. and 1300 A.D.
It's nothing compared to the great cathedrals that Europeans were building at the time. It's nothing compared to what the Romans had built a thousand years earlier. It's nothing compared to what various Middle Eastern, Central American and Southern American civilizations had been building at the same time, or had built some time earlier. It's nothing compared to what ancient Chinese dynasties had achieved.
Sorry, it just isn't impressive at all. It's somewhat disappointing that that's all that could be achieved.
(Score: 4, Informative) by HiThere on Saturday October 04 2014, @06:53PM
One reason is the tse-tse fly.
Seriously, think of humans as an invasive species. When they leave the area in which they've evolved, they leave behind the predators that have evolved together with them. Bears are dangerous, but they don't compare with leopards, when all you've got is a thrusting spear.
Then there's sleeping sickness, malaria, Ebola, etc. There are good reasons why Africa used to be called "the white man's graveyard" and they don't have much to do with the human inhabitants. It wasn't only the graveyard of white men, but the natives didn't get the same press.
That said, there's reasonable evidence that Africa is one of the places that discovered refining iron. So to claim that they've always been stuck in a valley is unfair. For that matter, Egypt is one of the ancestral civilizations. And Ethiopia was a strong enough country to keep them from expanding to the south (or we'd have had coffee a lot earlier).
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(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.
(Score: 2) by Non Sequor on Saturday October 04 2014, @07:56PM
The phenomenon of convergent evolution indicates that the shape of the terrain is dictated by the requirements of ecological niches with the preexisting gene pool being less important.
If you reran life on earth again, an awful lot of things would end up having analogous traits to what we have now because given sufficient time the same ecological niches would develop. Developmental biology would be different because evolutionary arms races might take place in a slightly different order and the organisms that get shoehorned into a particular niche might be different.
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