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If the world’s tape were rewound and played again …

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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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One Reply to “If the world’s tape were rewound and played again …

  1. 1
    bornagain77 says:

    Of related note:

    Darwinism more of a miracle worker than we thought:
    Evolution depends on rare chance events, ‘molecular time travel’ experiments show – June 18, 2014
    Excerpt: Tracing these alternative evolutionary paths, the researchers discovered that the protein – the cellular receptor for the stress hormone cortisol – could not have evolved its modern-day function unless two extremely unlikely mutations happened to evolve first. These “permissive” mutations had no effect on the protein’s function, but without them the protein could not tolerate the later mutations that caused it to evolve its sensitivity to cortisol. In screening thousands of alternative histories, the researchers found no alternative permissive mutations that could have allowed the protein’s modern-day form to evolve. The researchers describe their findings June 16, online in Nature.
    “This very important protein exists only because of a twist of fate,” said study senior author Joe Thornton, PhD, professor of ecology & evolution and human genetics at the University of Chicago. “If our results are general – and we think they probably are – then many of our body’s systems work as they do because of very unlikely chance events that happened in our deep evolutionary past,” he added.
    Lucky us! 🙂

    Playing Roulette with Life – Ann Gauger – June 20, 2014
    Excerpt: Think of it this way. When playing roulette, if you are looking for a specific number (mutation), you may have to wait a very long time to win your bet. You could then try again for another win, but you’d probably have to spin a long, long time to get the next winning bet. In fact, if you did keep on winning, spin after spin, everyone would wonder how you were cheating. Repeated bucking of the odds is always a sign of intelligent agency. Just ask the casinos.

    Also of note, rumor mill has it that Dr. Behe is also going to comment on Thorton’s latest paper.

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