Lenski experiment and falsifiability

Faith & Science Conversation
59

Very much appreciated, and I think I follow you. Let me clarify, and see if I follow you properly, I fear I may not have explained myself properly:

—I have no issue whatsoever with the continued existence of bacteria, or the fact that some bacteria have remained unchanged. If they are “fit” and functional, they will remain. One branch may develop some new and novel feature, but unless its fitness is so significantly greater, or the environment changes to make the previous version significantly less fit, then the old version will certainly stay around.

For instance, in the presence of an antibiotic, ALL the previous versions will die out, and only those with the resistance will remain to continue to live and pass on their genes. But there are certainly cases where a new, novel feature develops, and provides enough of a novel benefit so that the new version will grow and thrive… but there’s nothing in the environment that makes the old version particularly unhealthy, so the previous version will continue to thrive.

I have no issue with that aspect of evolutionary theory at all. When I say I have problem if bacteria remain unchanged for 2 billion years, I mean to say that my problem is if EVERY AND ALL bacteria remained so unchanged for 2 billion years, and NONE of them exhibited ANY change. Surely, some of them are fit enough, have their “niche,” and will continue. But if I observed a population that never evolved a new characteristic whatsoever, this I feel would disprove the basic theory.

That is of course why I fully embrace the basic microevolutionary theory - it is clearly demonstrable, repeatable, testable, and observable. I’ve done it myself. We see it in animal breeding as well as on Petri dishes.

So to summarize by example, and see if you follow my objection: At one point, a bacteria without a flagella evolved to have a flagella. Perhaps the flagella provided such a benefit that all its descendents had an advantage in survival, and thus the population of flagella-bearing bacterial grew and thrived. But this did not mean the previous version was in any way “unfit,” so the previous version, without the flagella, continued unchanged. — This basic concept I have no issue with whatsoever.

My objection would be if we observed a particular population of bacteria for a zillion years, watching zillions times millions of generations and having allowed for billions of zillions of organisms to live and thrive and experience zillions of mutatations, but during that whole period, they never evolved anything novel and complex that was even remotely comparable to a flagella…

At THIS point, I start to doubt whether the proposed mechanism (unguided natural selection acting on random variation) could actually accomplish what it claims to be able to do. It isn’t the continued existence of the old model, it is the failure to produce any new models, from which my skepticism would stem… which leads me to your other points, but I’ll get to those in a separate entry…

60

These are very thoughtful and apposite analogies, so if I may respond…

I wouldn’t disagree with this in principle. The difference for me being, with a clock, I can open it up, inspect it, see this gear connected to this one, see that if I move this it moves this one, and there is nothing at all to me that is categorically different that would have to happen that isn’t already built into the mechanism of the clock.

For this reason, I have no issue when people line up multiple fossils of horses, or of elephants and mammoths, or similar dinosaurs, or the like. The micro evolution that creates this very kind of variation is well documented, tested, repeated, utilized, and easily explains that kind of variation, and if there are “gaps” in the fossil record between two such exitinct animals, the process we are capable of observing is an adequate explanation for such, and thus I can assume they are related even if I don’t have a specific fossil.

But then there changes that don’t have that kind of explanation. If someone told me that a digital clock also changes with slow movements… that the digital 2 for instance becomes a 3 by that vertical line on the bottom slowly moving from the left to the right… and I open up the clock and find no mechanism that would account for that movement, then I remain skeptical.

These are the kinds of leaps I see in prokaryotes to Eukaryotes, to multi-celled animals, land animals to whales, echolocation, flight, etc. I do not see a mechanism observed, repeated, tested, etc., that is capable of producing that kind of change.

Which leads to…

We do see some significant changes, certainly. But consider, I could take some work of fiction, create a random letter generator in my computer, and set it up so it cross references the dictionary, and accepts only those variations and mutations and pass that make a new word. Occasionally that may make some impressive changes that are “beneficial” on the micro-level, changing “Brother” to “Bother” or “son” to “sin”. That process could conceivably “improve” Hamlet or Henry V. There are plenty of internet examples where a “mistake” of one letter made what some would call an “improvement” (usually with very comical results). So any particular instance or case is hardly worth disputing.

But if someone tried to tell me that a particular novel had been constructed by using this process, with all the detailed plots, the complex relationships between the characters, the carefully crafted mystery or the flow of the story… I’d remain very skeptical indeed.

That is the basic point at which I lose faith in evolution… when someone points to a small change as “proof” of a large scale macro change; the large change simply explained as being the cumulative effect of the small changes we are able to witness, no?

By that logic, No one should doubt that I could swim unassisted from Guam to Hawaii. After all, I can swim 2 miles unassisted, and the trip from Guam to Hawaii (3,950 miles) is simply the cumulative outcome of one 2-mile swim after another.

61

On one hand we have a human conspiracy involving science. On the other hand we have a God conspiracy involving revelation. Or

On one hand we have science and the OT, and
On the other hand, we have personal interpretation issues. Science cannot rest and establish dogma, because it is in a constant state of change. The OT was given thousands of years ago, and does not evolve. Calling the results of empirical endeavor a truth, leads to misleading conclusions. Just because empirical evidence seems to be the most reliable, it does not nor cannot approach the whole of a reality that includes spiritual reality.

If you dismiss the OT as just a product of human endeavor with no spiritual connection at all, then most would bet on today’s empiricism. If you are going to include a spiritual side to reality, empiricism only gets you half of the picture.

62

But Bible interpretations and theology certainly do.

Something can be true without speaking to the whole of reality. 2+2=4 even though it does not have a spiritual dimension. Science certainly can make true claims about reality, even though it lacks the tools to describe the spiritual dimension of reality.

63

Theology is the abstract work of figuring out the spiritual. Mathematics is the abstract work of figuring out the physical. But theology is the human interpretations of the spiritual not the authority. I think math is God’s work at figuring out the physical. God lets us use math as an authority, because God does not claim authority over math.

64

I’m wondering what your evidence is for this assertion. I’m not seeing it, but maybe I’m not understanding you correctly.

Take humans and “primitive primates” (whatever you mean by that). Would you accept the last human/chimp common ancestor as “primitive”? If so, we can directly look for the necessary changes by comparing the present-day human and chimp genomes.

When we do that analysis, we do not see evidence that much change is needed. Very little, in fact - and easily obtainable within the timescale (4-6 MY).

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65

Indeed, I am sure you could do so, so long a boat picked you up every 2 miles for rest and refueling. After awhile, you might even make 3-4 miles daily.
The conversation sort of reminds of the now nearly iconic example of bacteria growing across a gradient of increasing antibiotic concentration

In the lab experiment, recall that the environment was a homogeneous agar plate with the only variable being antibiotic concentration, and each of the branches represent mutations. Now, expand the Petri dish to the size of primordial oceans, and the environmental changes to those of the whole earth, and imagine where the branches lead.

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66

Going back to the original question, it might be good to review what the Lenski experiment did prove:

  1. All 12 lines evolved a fast glucose metabolism quickly
  2. 5 of 12 lines developed speciation the fast glucose metabolizers made a lot of anenergy rich waste product (acetate if I recall correctly) which some e coli developed a metabolic pathway to use
  3. One line exhibited a contingent mutation which with a second mutation vastly increased its population i.e success showing that contingent changes in evolution are possible.
  4. The e coli evolved in 3 discernibly different ways which show that the changes were not pre-programmed into the original e coli genes

So it showed evolutionary processes, It did not answer all questions but what experiment ever does that?

Could the Lenski experiment be considered meso-evolution?

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67

The duck-billed platypus: part bird, part reptile, part mammal — and the genome to prove it.

68

Or another example for us non-swimmers.
I can walk from my house to the local shopping centre; about 1 mile. Hence I could walk from my house in Brisbane to Australia’s capital, Canberra, 745 miles. And if I can do that I could walk from Canberra to Wellington, New Zealand, 1446 miles, it’s only twice as far.

Well, you could try it …

69

You totally have that capability, with adequate rest and refueling. You probably walk that distance in an average year anyway. Not really sure what point this is trying to make.

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70

The basic idea is that, while any one small step is not improbable by itself, the cumulative effect is not so. If I came in my home and saw a 6-sided die on the floor with “6” showing on top, it being dropped that way randomly is a very reasonably hypothesis.

If I saw 20 6-sided dice all with 6 facing up, not so much. Someone was without any doubt at work.

Similarly, I know that I can swim, unaided, without stopping, for 3 miles. But I would not accept the claim that someone swam, unaided, without stopping, from Hawaii to California, even though the latter is simply the cumulative effect of the former, repeated many times.

71

Hi Daniel,

You should be thinking of swimming whales, not swimming humans. A whale swims maybe 100 miles in a day, but it can swim a distance of many thousands of miles over a period of months.

Yours,
Chris

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72

With a little bit of robotics and computer vision, I could design a machine that rolled the dice, then selected for whatever number I thought appropriate. It would be a simple random variation + selection algorithm, also known as an evolutionary algorithm.

Likewise, I believe that evolution, like everything else in the universe, has a Designer. If we see evidence of an evolutionary algorithm being carried out by robotic arms and computer vision, though, why not just follow that evidence to its logical conclusion? This is what biologists are doing; they see evidence of the evolutionary algorithm at work, and they see the forces involved. Unfortunately, IMO, not all of them perceive the Designer.

Yours,
Chris

73

To walk from Canberra, Australia, to Wellington, New Zealand? No I totally do not have the capability to hold my breath that long.

74

We can dicker about the “swimmability” or “walkability” of this or that, but to do so is still to accept a bad analogy. It’s encouraging the relapse back into thinking that evolution has to accomplish things nearly all at once. Or that hundreds of mutations all need to be nearly simultaneous to make an eye ball (or some other appendage) suddenly pop out where none was before. But it doesn’t work like that.

A better analogy would be to note that ancient people in boats were able to traverse several hundred miles of ocean to reach such-and-such island. If they could do that, then their boating descendents may spread out even farther … (and they do; spreading Polynesian populations around the South Pacific). But it almost certainly wasn’t one early heroic adventurer that made the entire journey to all these islands the moment their boating skills became sea-worthy. It unfolded most likely over many generations.

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75

Reminds me of the game of Yatzee. The highest point is achieved when all the dice are the same. You roll the dice, keep what you want and roll again. Ultimately, you get all 6s but it is achieved by randomness along with selection.

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76

I think it’s quite a good analogy. Mutation + Natural Selection will allow an organism to explore the island of its population gene pool but to get to another island requires a leap beyond the capability of that mechanism.

That’s why we can observe rapid adaptation such as Trinidad guppies, beaks on Darwin’s finches, nylonase, Cit+, etc, but have a dearth of observation of real novelty.

77

I think that is a valid observation, and indeed is the struggle we have in visualizing how things came about. It is easy to see how all cats are related, but to follow the process further and further back to where there was a common ancestor with an elephant and with us is difficult. Yet, that is where the fossil record takes us, and it is confirmed with genetics, and is consistent with the measures of deep time.

78

What stops this process (over longer timescales)? What (for example) was “unreachable” when it came to humans and chimpanzees diverging from a common ancestor?

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