Neapolitan

I guess what I mean is when two scientist are in a lab doing a study of something scientific, or doing an experiment for the sake of science, the mention of "evolution" in a conversation is quite mundane and non-eventful, but say two non-sceintist are conversing about science the mere mention of "evolution" outside of scientific world that dialogue can spiral out of control into an heated argument. That's what I want to avoid.

And right now I feel like you're implying the general populace is me.

I think the evolving part is just as interesting as in the result of multi-cellularity.

Well I wasn't excited too much about the experiment because they seem to rig it for the desire result, not because I do or don't believe in the frequency that mutations occur.

I guess the page I was coming from was like: Was multi-cellularity already a forgotten part of this organanism pre-historic past? Was there some environmental change that forced this multi-cell yeast of the past to evolved in singlular cellularity of today. But still even after the evolutionary step it kept those multi-cellular codes in it's DNA but they remained dormant, it never reach multi-cellularity form because whatever environment that organonsim once live no longer exist, and in the new environment singular-cellularity was more advantageous for survival. Then along came a scientist and he did an experiment by shaking vials, in reality he didn't forced evolution on the yeast but unwittingly unlocked a pre-existing code that was already there - the multi-cellularity code. I think that is more my point than the validity of evolution or how much I know about evolution.

That's the whole problem I don't really trust the procedure - not that that I lack the understanding of what is going on with the experiment.

Well it depends - they might die out. I wouldn't rule that out entirely, statistically speaking there could be some environment somewhere on this vast planet where multi-cellular brewer's yeast could survive in - in a hypothetical scenario - there could an environment that could be similar to that of the experiment.

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Guybrush

The reason the evolving part is not as interesting is that it's been proven many times before and would show nothing new. Many times, micro organisms have adapted to artificially induced selection pressures

This is pretty much the plasticity scenario I mentioned in my earlier post. I'm sure they're trying to keep up with the genetic changes of the organisms and will document proof.

I should perhaps mention that an example of evolution does not necessarily require new mutations. We call it evolution even when the allelic frequencies differ from one generation to the next. That means that if there is two versions of a clumping gene, one which creates a unicellular yeast and another which makes a multicellular type yeast and in the generation you're looking at there is 9 unicellular genes for every 1 multicellular gene .. if the multicellular type yeast have more reproductive success, in the next generation you could have 7 unicellular gene versions for every 3 multicellular genes.

We call versions of genes alleles. In this case, even though both alleles were present at the start, the ratio between two alleles has changed from one generation to the next. As a result, the genetic makeup of the yeast population has changed somewhat. That's also called evolution.

edit :

The good old Hardy Weinberg principles demonstrate what conditions you'd have to meet in order not to evolve.

• Population size has to be huge (infinite size basically)
• Mating has to be random (no sexual selection)
• There can also be no non-sexual selection pressures
• There can be no mutations
• There can be no gene flow (gene migration from other populations)

These criterias are used as a reference to see how fast a population of animals evolve by looking at specific alleles and monitoring how they change in frequencies from one generation to the next.

If you understand the concept of evolution and these principles, you'll see that life can't not evolve.

edit 2 :

For the record, I don't believe that what we're seeing in the study is merely a change in the frequency of old alleles. I'm just saying that you could call it evolution even if that was the case. As it's a novel trait which the yeast seem to have adapted over time (gradually changing the way they work/look/behave), I'm still sure they will document changing DNA and not just changing allele frequencies.

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Janszoon

So you want to avoid talking about reality because there are some crazy people who get offended by it?

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MoonlitSunshine

That's.... kinda the point. You understand the concept of Natural Selection? The scientists wanted to show that a usually uni-cellular organism could be forced to evolve into a predominantly multi-cellular organism, provided that it was "optimal" to do so. In order to show this, they "rigged" the experiment so that the multi-cellular version should thrive and dominate. This is exactly what happened.

The "removing" of the uni-cellular free floating yeast at intervals was used to emulate "dying out" in nature - think of it like a plant evolving in two strains, one which kills what eats it and the other which doesn't - the predators would learn over time to eat only the non-lethal one and thus the non-lethal one would eventually die out (or at least shrink vastly in population) over time, provided it didn't have other more profitable mutations like a faster propagation rate.

"Evolution" isn't just the random mutation of organisms. Mutation happens as a matter of course, everything mutates, Evolution is the combination of Mutation and Natural Selection, where the Mutations which survive more successfully naturally grow to form the dominant part of the base population.

To relate that to this experiment, the environment was set up so that multi-cellular life had a greater survival chance. Their method of doing so might have been rather crude, but it was as effective and essentially equivalent to the free-floaters "dying out" due to other more natural reasons.

Or at least, that's how I've come to understand it.

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duga

This thread is the perfect example of a lack of understanding and thus non acceptance of firm data. Neapolitan, I applaud you getting in on the discussion but seriously... You don't understand what is going on fully. Either that or you are trying so hard to play devils advocate that it is coming off that way.

Trust me when I say a scientist's biggest critics are other scientists. Paper go through scrutinous reviews from peers and experts in the field so when the paper comes out, you can be fairly confident it represents a reliable piece of evidence towards the concept they are studying. Granted, this isn't always the case which is why we are still critical.

This study in particular seems like a solid bit of research. It doesn't prove evolution on a grander scale, but it is just one more piece of evidence (on top of mounds I other bits) that prove the concept.

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Neapolitan

^ Duga,

Instead of whole heartily agreeing with this experiment I think to myself isn't there something in this experiment that should had done differently. How about you are you totally fine with the proceedure? If there was something you would had done differently what would it be? Many experiments I hear of uses a placebo, maybe in this case a placebo should had been used. Say for instance have three unmarked vials give two scientist the brewer's yeast and the third scientist amoebae as a placebo and see if the same result of multi-cellularity would happen for all three or just the first two.

Yeah, pretty much most of the time - MB in a way is an exscape of reality for me.

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Janszoon

*Waves to Neapolitan from the back of a giant blue dragon.*

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Guybrush

I think you misunderstand the point of having a placebo. When testing drugs, you use placebos because people taking drugs commonly have something called a placebo effect. What that means is that whenever someone takes a drug which is not very harmful, the drug should be expected to have a positive effect regardless of whether or not the chemicals in the drug actually have an effect. People's belief in medicine makes it work, even when it has no effect on it's own.

That makes it hard to test new drugs because when you see beneficial effects, you don't know whether it's caused by the drug or just the placebo effect. So, because of this, people partaking in medical experiments may recieve placebos (they don't know whether they get the placebo drug or the real drug). Then the effect on their health is registered. For a drug to pass such a test, it needs to have an effect which is significantly better than the placebo effect.


Needless to say, a placebo is not needed for this evolution experiment as there are no placebo effects going on here. They're not testing a drug. In my opinion, the experiment is just fine and I was actually impressed with how easy and elegant it was.

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duga

Agreed.

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Neapolitan

*waves back to blue dragon*

Yeah I guess we can agree that there's a sort of elegance to this experiment by how it was conduct with simplisticity, a few brewer's yeasts, an organically rich broth, and a vial to be shaken (not stirred) but imo the methodology of scientific endeavor is suspect. I guess I was expecting more information from what was going on behind the scene genetically. Like during the first stage of the experiment when the heavier yeast fell to the bottom presumably they were bi-cellular, was this an actual mutation taken place or alleles? And in the one of the final stages of the experiment those multi-cellular grouping (when they shook the vial some fell apart and the strong bounded multi-cellular yeast remain those other that fell apart) those that were loosely bound, was there specialization going on within the loosely bound multi-cellular group, because if there was why was there a specialization before a strong cellular bound that would keep them together as a multi-cellular organism?

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