Lenski’s Long Term Evolutionary Experiment
Richard Lenski began the LTEE with 12 populations (six 
and six 
) of the bacterium Escherichia coli on 24th February, 1988. The experiment is currently housed at Michigan State University and has run continuously apart from a short break while relocating to the present site and another during the height of the Covid-19 outbreak.
The method is very straightforward. Each 24 hours, from flasks of the bacterium in a growth medium known as Davis minimal broth dosed with glucose at 25 mg per litre (DM25), are extracted by pipette a random sample of 0.1 ml which is added to a new volume of 9.9 ml DM25 in new flasks which are then incubated at 37°C for 24 hours and the procedure repeated indefinitely.
What the experiment does is to provide a consistent, stable and simplified niche for the twelve lines allowing them to proceed in parallel isolation (great care is taken to avoid cross-contamination). This allows the researchers to test whether evolutionary change is inevitable, repeatable or unpredictable.
One objection often made by critics is that, being designed, the experiment is not a true test of natural evolution. But Lenski chose the environment, he does not design the bacteria. A random (the flasks are continuously agitated on a mixing plate to ensure uniform distribution of cells) sample makes it through to the next generation (70,000 and counting in the thirty years the experiment has been running) but, over time, the twelve lines have undergone changes that can be observed. Cells have become larger, redundant (in the experimental niche) parts of the genome have become broken.
The most spectacular change so far has been the arrival of the ability of one line to metabolise citrate aerobically. The change has been well-studied because deep-frozen samples are retained every 75 days and DNA sequences (thanks to cheaper and quicker DNA sequencing) can be compared to match genomic changes against phenotypic changes. The ability to digest citrate involved changes at more than one locus, a beautiful illustration of neutral evolution and genetic drift.
The LTEE also is an excellent refutation for Creationist John Sandford and his “Genetic Entropy” idea. I’m sure others can point out errors but this OP is meant only to provoke discussion and not to be authoritative so please jump in with comments.
Blount Lab
https://www.blount-lab.org/publications.html
There’s a PDF available for download at the Blount Lab link above, a reprint from Scientific American, that includes a not-too-technical description of the LTEE and the evolution of aerobic citrate metabolism.
ETA: Replaying Evolution
“The State of Israel has been accused of being a state-sponsor of terrorism,and also committing acts of state terrorism.”
I am just curious why you have commented about this. Is it because there have been so many acts of terrorism you can’t decide which one to talk about?
I know Israel pays students to post pro-Israel online, and on social media.
I am just curious why you haven’t posted anything about this…hmmmm.
I know you did post something to the affect of the reason Israel has to shoot Palestinian children is because they government hasn’t spent enough money. I think you also hinted it was the kids fault…
Weird Alan Fox (Dershowitz?).
Source for your quote. Who wrote it? When?
phoodoo,
Ah, 2013.
@phoodoo
Do you think we have student Israeli moles here at TSZ?
Nope. I was hinting that during the Troubles, youngsters would gather in numbers to confront British troops. Some suggested they were at times being organized by Nationalist activists, being exploited for headlines about the brutality of British oppression. If it was a strategy, it was effective in gaining sympathy for the Nationalist cause. Personally, I see no justification for Northern Ireland to remain as a UK possession and the sooner all the people of Ireland move to independence the better.
Equally, there needs to be an equitable solution to the Palestinian situation.
And the Rohinga
And the Uighurs
Hong-Kong
The problem with this assertion starts with the false equivalence of bacteria and humans and goes on from there. What the LTEE does do is show that fixation takes a lot of generations and given lots of generations a de novo functional sequence (not copied) did not evolve. It also showed that fixation takes very strong positive selection to be effective in providing evolutionary change.
What the experiment did do is help provide evidence for Behe’s concept of devolution.
So humans suffer from genetic entropy but bacteria do not? Is that your claim?
Try justfing it why don’t you.
Function changed. Therefore something evolved from the start to when it changed. Argue that it was a copy all you like, or that not really ‘new’ but the fact remains that function changed. And no designer in sight.
Did it? Why don’t you actually make that argument then?
And yet new function appeared and the bacteria are still going strong. There appears to be no devolution going on. Behe disproven.
It’s funny how you want to have it both ways. Genetic entropy does not apply to bacteria, for some unexplained reason, but nonetheless the bacteria are devolving.
If you want to call evolution devolution and accept that it works as evolution does, then that’s actually fine. You are aligned with everybody else in essence.
It’s amusing how specific colwed has to be:
It seems the only thing that would satisfy this constraint is Intelligent Design. i.e. a sequence that was not there in one generation is now there in the next, entire and complete.
colewd’s misunderstanding of how evolution is actually proposed to work by definition precludes evolution ever working. He has defined it away.
Things only evolve if they bear no relation to what came before.
Hey, colewd, remind me what the precursor to C++ was, that you were using as an example of something new with no precursors? It turned out that B came before C++.
Your misunderstanding there is the same as this. You simply don’t know enough about it to make statements like you are.
Hang on. Did I read correctly that you accept that evolution by natural selection is a real thing?
I think it depends on the day of the week. 🙂
I’ll take what I can get 😆
Corneel,
Sure it’s a real thing. What the experiment demonstrates is its capability and its limitations.
https://www.mcgill.ca/oss/article/critical-thinking/dunning-kruger-effect-probably-not-real
The stupid Dunning Kruger effect is even more stupid than you thought.
Skeptics can’t get anything right.
Well, I am very happy to hear that. Well done, Bill.
That was sort of the point of the experiment, yes. I believe we disagree what those capabilities and limitations are though. So why wouldn’t the findings of the LTEE generalize to other organisms?
Can you?
What is the origin of species according to phoodoo? To colewd?
If you never do anything at all you’ll never get anything wrong. That appears to be the tatic you and colewd have chosen. Criticize others for trying but don’t try yourself.
You seem to be happy with ‘evolution did not do it, ID did’ and indeed happy to just leave it at that. No more info needed. Case closed.
Five year olds have more curoristy then you two.
But isn’t revisiting and attempting to validate others’ results being skeptical. Not seeing your logic here phoodoo. And you can’t blame that on Dunning and Kruger now. 🤗
Compare and contrast to the Bible, unchanged since inception. God wrote it, phoodoo believes it. Slavery? Good thing.
Being critical about something you are doing much worse yourself is par for the course it seems.
They mistake their lack of flexibility for knowledge, and they mistake willingness to change when new information is found for uncertainty.
That’s why people like phoodoo and colewd find their last refuge in places like this with the few people willing to engage their sophomoric ID advocacy. They’ve nowhere else to go, professional avenues are blocked to them by their own unwillingness to engage.
Nobody is interested in what they are selling, apart from to poke fun and laugh.
OMagain,
I do find it odd that some still cling to the concept of “Intelligent Design”. I guess latecomers to the idea, as nonlin appears to be, are perhaps unaware of the history of the ID movement and its core dishonesty
I guess there’s a parallel with supporters of Trump still clinging to Trumpism. They’ll likely still be around long after Trump’s rejection by the electorate.
I imagine there’s a big overlap between Creationists and Trump supporters, too.
Not you, I know, phoodoo.
Corneel,
Single cell vs multicellular and all the differences that go with it including a confined environment, fast reproduction rates and simple cell division reproduction. The waiting time problem of fixation is a bigger challenge for a mobile multi cellular organism.
How, according to Intelligent Design, is that problem resolved?
Could it be design by any chance?
When and how does your designer make changes in multicellular organisms?
OMagain,
According to the Bible animals arrive on earth fully formed. Interestingly enough when you start from fully formed animals population genetics math works.
So you have resolved a scientific problem by invoking the Bible?
I’m sure humperdoo is proud. You do understand that’s not actually an answer to the question asked, right?
It’s like asking a child what two plus two is and they shit in their hand and proudly show you that instead. That’s you that is.
I also did not realise Intelligent Design has decided that the Bible is relevant. What makes you think the Intelligent Designer is also the god of your bible?
What evidence do you have for that?
narrator: colwed just shit in his other hand instead.
OMagain,
The existence of the Universe, Intelligent observers, and a book that tells us how it all started. It’s the only coherent worldview in my opinion.
How strange.
So, if you don’t start from fully formed animals then “population genetics math” does NOT work? That’s quite the claim!
Alternatively, you are not making any such claim and your “Interestingly enough” segue is an attempt to connect the unconnected. Woolly thinking yet again.
That’s only evidence that there’s a universe. Nothing else.
If we didn’t exist, nobody would be making the claim that we exist. But evidence of a magical being in the sky? Not at all.
There’s plenty of mythologies that “tell us how it all started.” Your book looks a lot like just one more mythology. Sorry.
If pretending that your mere existence is evidence for a magical being in the sky counts as coherent, I’d guess so.
But we all developed from single cells, Bill, even you. And math is a human construct that we use to build models. Reality doesn’t care.
Did you expect a book of mythology to state that animals arrived on earth unformed? Like one day a leg, the next day a brain, the next one a cell from the stomach, and so on?
How could anybody apply population genetics to unformed animals? Where do we find those? How would that work? Do you mean to say that geneticists have to put complete animals in a blender, rather than take, say, a tissue sample? Otherwise population genetics won’t work?
And you think that your worldview is coherent?
Entropy,
I disagree the Bible is mythology. I believe it is objective truth. You continue to reason in a circle.
DNA_Jock,
This is a burden shift Jock. Can you argue the position without committing a logical fallacy.
Alan Fox,
We are not a single cell reacting to an environment. Equating humans and bacteria is quite a stretch. 🙂
I don’t reason in circles. I think you mistake me for some guy who thinks in cart-before-the-horse terms. However, I reason according to the evidence, and the evidence shows that it’s but another book of mythology. Still, to the question: what else did you expect it to say if not that the animals came fully formed? One day a leg, the next day a brain, the next one a cell from the stomach, and so on?
Job.
You are correct. We are more bacteria then not if we count the cells.
https://www.nature.com/news/scientists-bust-myth-that-our-bodies-have-more-bacteria-than-human-cells-1.19136
Once again, shows what you know.
When asked a scientific question you respond with the bible did it. You asking for that is laughable.
When did it all start?
When did animals arrive on the earth fully formed?
6000 years ago? Or longer?
Why do we find a succession of forms in the fossil record instead of fully formed, say, horses?
etc etc. If your worldview is actually coherent it’d be trivial for you to answer these questions. It’s only coherent by your internal standards of ‘thinking’.
colewd,
I’m not talking about bacteria, Bill. You were once a single cell in your mother’s womb. As were all of us humans.
Entropy,
If you make a claim of truth without showing how the evidence supports it then you are reasoning in a circle. There is competing evidence in the Bible alone that it is Divinely inspired. From its cohesiveness over centuries to its prophetic claims. The fact that you are not supporting your claims beyond assertion supports the objective truth of Christianity. The tremendous investment made in Christian institutions in the last 2000 years support the belief that Christianity is the most coherent worldview. People don’t often invest money in something the do not agree with.
Alan Fox,
You are trying to compare bacteria with a eukaryotic cell that can differentiate and build body plans. You are essentially comparing a ball point pen to the space shuttle.
In addition the experiment did not even build an enzyme with the equivalent of 2 million human years of evolution. Why do you think Michael Behe cites this experiment as evidence of the limits of evolutionary theory.
Nah. I’m just not showing the evidence. That’s not the same as reasoning in a circle, since I’m not showing you any premises, let alone circular ones.
I doubt it. But that’s not what I’m asking.
I’m not discussing whether the bible is mythology or not, I already know it is. I’m asking a very specific question that you keep neglecting to answer.
Nope. It just reflects it to be in the main beliefs of the involved people.
Though the agreement is but a creedo.
Now, to the topic: what else did you expect it to say if not that the animals came fully formed? One day a leg, the next day a brain, the next one a cell from the stomach, and so on?
Really, I wasn’t. But eukaryota are simply a neat combination of an archaeon and a bacterium. Why reinvent the wheel when you can engulf and enslave what you need?
Because Mike is an idiot.
If that’s right, why should I worry? Six million years separates us from Pan paniscus and there was huge bias from the niche to reinforce the necessary changes. Lenski’s environment is stable. It’s strange we see any change at all, is it not?
Entropy,
He’s managed to make a career and supported a wife and nine kids. And he has some amazing hats. It’s not black or white.
If that’s all that’s a problem….
https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.15299
No problem!
It’s from this century, so you may not have seen it yet.
Also colewd:
Is your evidence for that claim the fact that the bible says it? If so, your idea of making a claim of truth and showing how the evidence supports it is wildly different from what a normal person would understand by that phrase.
By that metric Harry Potter really can do magic. It does, after all, say so in the books!
Because there’s no Intelligent Design experiments to cite?