What's not Macro about Chlorella v?

I responded to an off-topic question with an off-topic answer in another thread; my bad. But I thought the response deserved attention, so I'm hoping to redirect the discussion here.Hanno2 asked: To which I replied: To which Hanno2 responded: To which I now reply. It's not known to do so, and anyway, the only other organism in the culture was its predator, the flagellate. What about the evolution of an entirely new mode of existence - multicellularity - doesn't count as macroevolution? This is lightyears more advanced than new limbs or organs. This is an entirely new mode of existence for these organisms. These did gain something that was never there - multicellularity. Why would it?

Thread moved here from the Proposed New Topics forum.

At best, this experiment, shows that some Chlorella variants already had this ability and the predation highlighted those variants. But it looks more like they don't know what kinds of algae they had to begin with.Also, what is so amazing about multicellularity in algae? I should not be surprised if many forms of algae can exhibit, under various conditions, either unicellularity or multicellularity. They're algae.Furthermore, how could it possibly be known that Chlorella v. does not ever do this under any circumstances except this lab experiment? Wouldn't we have to carefully examine every Chlorella population on the planet to even begin to say that Chlorella couldn't already do this under various conditions? (And apparently they can because they did in this case...that is, if it there wasn't actually Coelosphaerium in the sample all along, and the flagellates simply gave the Ceolosphaerium the upper hand by eating most all the Chlorella).But this goes back to our old argument about it being "proof" of evolution, when all it does is show (unless it was actually a contaminated sample) that the variants with this ability already existed prior to the experiment...either that, or THIS is a case of on-demand evolution, which everybody, I thought, agreed doesn't happen. [color=#00ff00]{No, I remember now that CrashFrog does consider such examples to be evolution on the spot}Apparently Chlorella enjoy rapidly evolving: Here they go again!At least this example doesn't leave one wondering if the scientists involved can distinguish between Chlorella and Coelosphaerium. But it also leaves no doubt (to me) that the variants pre-exist the experiment (although I think they'd rather you not get that impression...they seem to be wording things so it appears that the Chlorella evolved on-demand.) Or did I misunderstand everybody, and ya'll DO believe in on-demand evolution?"Tired of waiting millions of years for things to evolve? You need Chlorella!"--an idea for an evolution commercial :^)Tear it up,
--TLThis message has been edited by TheLiteralist, 01-27-2005 04:59 AMThis message has been edited by TheLiteralist, 01-27-2005 04:59 AMThis message has been edited by TheLiteralist, 01-27-2005 05:03 AM

Which ones? If they had been known to already have this ability, they wouldn't have been keyed out in a different family. Your analysis is completely wrong. An algae that, hitherto, has always been unicellular? Oh, right. Nothing amazing about that. They key out in a different family! That's not just a new species or genus; that's macroevolutionary change at a very high level. Because if they did, we'd only ever find them this way. As it said, the new configuration was stable for decades; this is because it's so much better than the old form at resisting predation. Yes, of course, in the same way that almost everything is possible through mutation and natural selection. It was a monoculture of Chorlella, so no, there were no Coelosphaerium in the sample. There was nothing but Chlorella v. until the paramecium predator was mistakenly introduced. The problem for you is explaining where these variants came from in a monoculture. We have an explanation, of course - mutation. Your explanation appears to be that variants can just beam in to the chemostat whenever they please. I'm sorry? Where did I ever say this? Support or retract, please. Where? Where were these variants? How did they get into an isolated monoculture of Chlorella v.? The culture didn't start with these variants, because the Chlorella of this culture were unicellular. Where did these "pre-existing variants" come from, and how did they get into the culture? If the Chlorella that were already there were these variants, then why were they unicellular? If these variants have the ability to switch back and forth, then why haven't they switched back now that the predators have been removed?Your argument appears to be "this can't be macroevolution, because it actually happened." Pardon me if I don't find that very convincing. Or rather, it convinces me that you'll accept absolutely nothing, under any circumstances, as evidence that you're wrong.Edited to remove off-topic, mistaken dig at TheLiteralist. My apologies to him.This message has been edited by crashfrog, 01-27-2005 15:11 AM

What do you mean by on-demand-evolution? It seems to me you mean non-random mutations happening that guarentee a solution to the problem? If you don't mean a non-random mutation then i'm not sure what the problem is, because there's nothing bad for evolution if a helpful mutation randomly occurs after the predation starts.I'm no expert, but I imagine if you looked at the genome before and after you'd find many different changes, most of which do nothing to help stop the predation. These things reproduce so fast that they just get many more mutations, with more chance that once of them will have some sort of positive effect.It seems to me that you're ruling out any helpful mutations that happen after the predation as non-random mutations as if they happened because they needed to happen. If this is the case, i'm not sure exactly what you WOULD accept as evolution because the only other alternative is that mutations are not needed as some particular individual already had the capability. As has already been mentioned this isn't a possibility here because all the organisms originiated from a single sample that didn't have the ability to be multicelluar. The only option is that one of them aquired it through mutation.

Hi CrashFrog,Well, let me deal with this first. I said: I thought you did. I got this impression from This Message.From That Same Message, I also got the impression that you believed that variations prexist the conditions of natural selection.At any rate, in THIS thread, in the message to which this post replies, you indicate a belief in on-the-spot evolution, don't you? I find the idea of "monoculture" contradictory to the idea of random mutations. You can't have it both ways, can you? Start off with one cell, get all kinds of variations or start off with one cell and get a culture of clones. Which way is it?You are saying, then, that the Chlorella v. experienced ABSOLUTELY NO RANDOM MUTATIONS before the flagellates were introduced? Then, once the flagellates were introduced (via lab malfunction) SUDDENLY they started mutating away until they AMAZINGLY and QUICKLY hit the right mutation that would confer resistance to the flagellates--i.e., colonization. I find this difficult to believe. It is TOO AMAZING. It is not too amazing to think that Chlorella v. variants prexisted (via creation, mutation, evolution or what not) the experiment. But suddenly they hit the flagellate-resistant form at the same time that a lab malfunction floods them with flagellates, which begin eating them up into oblivion? Seems very non-random to me.I am still amazed that the Chlorella alagae managed to evolve into a form of algae that already exists. That's why I still tend to think that this is a contaminated sample.OTOH, let's say it's all true (I REALLY doubt it, but...), then you might consider that it began as algae and it ended up as algaie. So, no, I wouldn't consider it macro-evolution even if you could convince me of all the other stuff first, which would be difficult. Well, I missed it, I'm afraid. But thanks for removing it and apologizing. Unfortunately, I have not always succeeded in catching and deleting MY digs at various of you evolutionists.

Umm, its a strawman? The fact that the population is not clonal does not mean that it is going to have radically novel morphologies, such as the Coelosphaerium morph. If the culture is derived from 1 individual then you know that at that specific point in its history there was no genetic variation. A Chlorella monoculture is not the same as a completely clonal culture. If all of the organisms had the Chlorella morphology then the culture was entirely composed of Chlorlla morph Chlorella, subsequently the culture contained Coelosphaerium morph Chlorella. They weren't actually Coelosphaerium they would just key out to that species based on morphology.TTFN,WK

Okay. Monocultures are NOT clonal cultures, then. I can go with that. A monoculture would just tend to have a lot less variation than a non-monoculture, then, right? (But there WOULD be variation.)Unfortunately, I don't really understand what is meant by "key out." However, it is enlightening to me that: I will withdraw the idea that it was a contaminated sample then...it suddenly becomes idiotic. But, to me, it also makes it seem even a less-than-great example of macro-evolution. It was Chlorella before...it is Chlorella now.What do you think of the idea that the variant didn't exist until the flagellates were released into the sample? Personally, and at this point, it seems ridiculous to me that they variants didn't pre-exist the flagellate introduction--it just seems like a completely amazing coincidence that the chlorella population in this lab that's about to have this accident that will release flagellates into the population would just happen to develop this flagellate-resistant trait after the accident and before all the chlorella are eaten--I mean, THAT is SO AMAZING! The variants might not have been colonizing for any number of reasons, I think. Isn't it correct that algae that can colonize do not necessarily colonize? Or could they have been making very small, unnoticeable colonies?Thanks for the comments and the correction.--TLThis message has been edited by TheLiteralist, 01-31-2005 07:17 AM

That is correct. A key is a sort of algorithm used to identify an orqanism as belonging to a particular species. It usually takes the form of a series of binary options to describe the organisms characteristics, see here for an example. I find it quite reasonable that it could be a very low abundance trait which in the normal course of the chlorellas life would not confer any advantage. With the introduction of a high selective pressure such infrequently ocurring traits may be amplified and are likely to come to predominate.If you read the Boraas(1998) paper , which actually details the experimental replication of this change, you will find that they see normal predator/ prey fluctuations between the flagellate and the unicellular chlorella but that within 100 generations, not exactly instantaneous, they saw multicellular forms develop and begin to predominate.It is true that some organisms are only colonial some of the time, but the paper studied this possibility by culturing the colonial chlorella for several generations in the normal permissive media, and never observing any reversion to the unicellular form, until they were denied light.It is possible that there would be a weak form of this trait already, that every generation or so 1 or 2 clustering cells might arise, but the exprerimenters observed the normal culture of Chlorella over a long time period and never saw any sign of a frequent occurrence of such a phenotype, although there were occasional clusters they could not be ascribed to anything other than artefactual effects. It is not impossible to rule out some weak form of this trait pre-existing, but the trait has been radically intensified and stabilised to a set number of cells per colony, it is very hard to ascribe all of these to a pre-existing variant which went unnoticed in the parental population.I really reccommend that you read the paper, let me know if you have any problems with it.TTFN,WKP.S. While the larger colonial groupings may resemble Coelosphaerium the final steady state 8 cell colony doesnt very much, at least to my eye, do a google image search for Coelosphaerium and it should bring up a few examples to compare to the one in the paper.P.P.S. I'm wondering if this is another one that, like the nylon bug, should be treated rather circumspectly. This whole confusion over the keying issue and the frequency with which the same C+P phrase turns up in message boards all over the place makes me think that a lot of people put this forward as an argument who have absoloutely no familarity with the actual literature, especially since the reference given is almost always the 1983 Transactions of the American Geophysical Union paper rather than the much more recent, and actually easily available, 1998 paper in Evolutionary Ecology.This message has been edited by Wounded King, 01-31-2005 10:11 AM

No, I don't. Environment does not drive mutation, or determine the outcome of mutation.But mutations are constantly occuring. Certainly, in this culture, a mutation occured that allowed the Chlorella to become colonial. Probably many other mutations occured as well, for entirely unrelated things, but there was a selection pressure for resistance to predation, and colonality was selected.That's evolution. It doesn't matter when the mutation occured, and when it did had nothing to do with the conditions of the culture. What mattered was that a selection pressure existed that made that mutation highly beneficial, and as a result, that mutation was fixed in the population. That's evolution. Gosh, if only there was a mechanism that caused an organism to possess genetic material that it didn't inherit from its parent. Oh, wait, there is - mutation.A monoculture is not a culture of clones, precisely because mutation exists, and occurs. Where did I say that? You're the one saying that. Originally, being a monoculture, there was only one variant in the test environment. Through many generations, there would have come to be many variants - every individual is a variant - in the environment, due to mutations. Then, a selection pressure selected among these variants, and a gene shared by a small fraction of the population became fixed in all members of the population.That's evolution. Oh, god. Of course they're still algae. That doesn't make it not macroevolution. Do you listen to me when I tell you that species essentialism is dead? Because its like I'm talking to a brick wall when I say that, over and over again... if you don't know what it means, now is the time to say so.

Of course it existed prior to the introduction of the flagellates, or else there would have been nothing to select.You don't seem to understand, or maybe I misunderstand your argument. If you agree that it was mutation that allowed the Chlorella to become colonial, and you agree that the reason that mutation became fixed in the population was because of the selective pressure of the flagellates, then what are we arguing about? Because you've precisely described the process of macroevolution.

I'm sorry that I even wrote it, and as I look back on this thread - even the messages I posted not minutes ago - I'm shocked by a level of stridency in my tone.I'm going to try and scale that back in future messages; it's disrespectful to you. I hope you'll accept my sincere apologies, and my promise to attempt to steer my reactions back into the realm of civility.

You're absolutely right, WK. However, the issue presents a quandry. On the science side, most of us familiar with the subject accept Chlorella, or the nylon bug, or my personal favorite Volvox clusters, as good examples of evolution. We (most of us) understand that natural selection can only operate on pre-existing variation - whatever the source and whenever it arose. However, to answer the creationist contention that either "no new information" can arise in a population or that "macroevolution has never been observed", which show fundamental lack of understanding of the basics, we need to have something we can point to as examples. Explaining the details may be intellectually honest, but as you've had to do with TheLiteralist (who's more than passing intelligent), getting down to the fine details of the discussion over just what that means usually ends up with the creationist triumphantly shouting "See, I told you nothing new ever happens. Evolution is falsified!" Forgetting, of course, that ns acting on variation IS evolution. Without variation, evolution doesn't happen.So what do YOU do when a creationist crows that X couldn't happen? What examples do YOU use to illustrate the concepts of macroevolution or rm+ns=evolution? I'm all for being honest in our appraisal of what constitutes evidence for evolution. But what kinds of evidence and how do we present it in the context of the EvC debate?

In and of themselves the research into nylon digesting bacteria and the colonial morph of chlorella are both perfectly acceptable examples, I just feel that the way they are put forward is frequently from 2nd hand sources.By all means use the nylon bug, but what worries me is the dozens of people who are giving the highly innaccurate NMSR site as a reference for the Nylon bug. This is especially lamentable given the other excellent articles in the field which that site ignores.Similarly the colonial chlorella evidence just seems to be stuck on the initial 1983 reference, and that especially unhelpful keying out to coelosphaerium point.I think the correct sort of evidence would be the primary literature and preferably the most up to date relevant primary literature.TTFN,WK

Okay. I concur wholeheartedly. For some reason I thought you were arguing something else entirely. Appreciate the clarification.