Evolution Hidden in Plain Sight – Phenomena: The Loom

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It’s hard to believe that Escherichia coli could have any secrets left.

 

For over a century, scientists have picked the microbe apart–sequencing its genes, cracking its genetic code, running experiments on its metabolism, earning Nobel Prizes off of it, and turning it into, arguably, the most-studied organism in history.

But as deep as scientists dive, they have yet to touch bottom. That’s in part because Escherichia coli is not fixed. It continues to evolve, and even in the most carefully controlled experiments, evolution leaves behind a complicated history.

Twenty-five years ago, Richard Lenski used a single microbe to seed twelve lines of bacteria. He fed each line a meager diet of glucose, and the bacteria have been adapting to this existence in his lab at Michigan State University ever since. (Here I’ve gathered together a few pieces I’ve written over the years about the 58,000-generations-and-counting Long-Term E. coli Evolution Experiment.)

In 2003, Lenski’s team realized that something utterly unexpectedhappened. One of the hallmarks of Escherichia coli as a species is that when there’s oxygen around, it can’t feed on a compound called citrate. But one day a flask turned cloudy with an explosion of E. coli that were doing just that. The change was so profound that it may mean these bacteria had evolved into a new species.

Written By: Carl Zimmer
continue to source article at phenomena.nationalgeographic.com

3 COMMENTS

  1. Richard Lenski’s experiment is painstakingly described in the chapter ‘Before Our Very Eyes’ in The Greatest Show on Earth by what’s his name.

    I’d forgotten about that; from now on when someone questions evolution I’ll refer them to that account of Lenki’s work; and then leave them stew!

    Previously, I’ve always sited the Recurrent Laryngeal Nerve as the best evidence for natural selection, but now I’ve got two shots in my locker.

    Of course, there are many thousands more to choose from, but these two are clear, simple and easy to explain even for a lay person such as myself.

    However, much rides on the degree of obtuseness of those simply unwilling, or perhaps even afraid, to make the effort to grasp even the most easy to understand elements of the theory, despite the fact that it knocks imaginary friends into a cocked hat.

    • In reply to #1 by Stafford Gordon:

      Richard Lenski’s experiment is painstakingly described in the chapter ‘Before Our Very Eyes’ in The Greatest Show on Earth by what’s his name.

      I’d forgotten about that; from now on when someone questions evolution I’ll refer them to that account of Lenki’s work; and then leave them stew!

      Previousl…

      Add ring species to that list, I find that’s a great point to put forward to someone who demands to “see” evolution

      Although I think when it comes to arguing with the wilful ignorant it’s all a bit pointless. I have had to deal with someone stating unless they can see it happening in their own lifetime they refuse to accept it which to me is a bit like saying unless the victim tells us who did it I refuse to accept they were murdered

      • Add Culex molestus to our growing list!!!!

        i am using this article as an opener to our evolution unit. The unit follows our molecular genetics unit which I closed with an excerpt from The Ancestor’s Tale involving Spiegleman’s Monster (add that to the list too!!).

        And, thanks Stafford for reminding me of richard’s awesome description of Lenski’s research from TGSOE. I’ll be steering the students towards that as well.

        BTW, I also cherish obvious examples of the refuting of an intelligent designer. “Why not just DESIGN a DNA polymerase III that can travel both 5′ to 3′ AND 3′ to 5′??????” Then there is no lagging strand, no okazaki fragments, etc… Damn, that’s the way I would design it…. So would a kindergarten student.

        In reply to #2 by SaganTheCat:

        In reply to #1 by Stafford Gordon:

        Richard Lenski’s experiment is painstakingly described in the chapter ‘Before Our Very Eyes’ in The Greatest Show on Earth by what’s his name.

        I’d forgotten about that; from now on when someone questions evolution I’ll refer them to that account of Lenki’s work;…

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