If the world’s tape were rewound and played again …
|June 21, 2014||Posted by News under Evolution, News|
Would it play out the same way?
This interesting Nautilus article interviews a number of interesting figures on the question:
The Long-Term Evolution Experiment, as the E. coli project is known, has surpassed 60,000 generations now, giving Lenski a deep data set from which to draw inferences about the interplay of contingency and convergence in evolution. Subtle changes in the bacteria’s DNA that make them larger and better able to proliferate in the flask have been relatively common across the groups. At the same time, Lenski has witnessed “striking” cases of contingency, in which one population did something completely different than the others. But as in convergence, he adds, these transformations weren’t entirely random.
“Not everything is possible,” no matter the process, Wake explains. “Organisms evolve within the framework of their inherited traits.”
Simon Conway Morriss says,
oes the rarity of any particular sequence of events imply that major shifts in evolution are unlikely to be repeated? The experiments suggest that’s true, but Conway Morris firmly answers, no. “You’d be daft to say that there aren’t accidents of one sort or another. The question is one of time scales,” he says. Given enough years and enough mutating genomes, he believes that natural selection will drive life toward the inevitable adaptations that best fit the organisms’ ecological niche, no matter the contingencies that occur along the way. He believes that one day, all of the E. coli in Lenski’s experiment would evolve to consume citrate, and that all of Liu’s viruses would eventually scale their adaptive Mount Everests. Further, those experiments were conducted in very simple and controlled environments that don’t come close to matching the complex ecosystems that life must adapt to outside the lab. It’s hard to say how real-world environmental pressures might have altered the results.
File under: We just don’t know.
See also: The Science Fictions series at your fingertips (origin of life)
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