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Author | Topic: An ID hypothesis: Front-loaded Evolution | |||||||||||||||||||||||||||||||||||||||||||||||
Granny Magda Member (Idle past 294 days) Posts: 2462 From: UK Joined: |
In my first essay, I stated that a premise of the FLE hypothesis is that eukaryotes and Metazoa were front-loaded. This is the premise of front-loading, and the one from which we can draw testable predictions. But you're just asserting that. There is no reason to assume it. That completely undermines any arguments based upon the assumption.
And no, I don't think I'd particularly care for your guess about why the FLE posits this as an initial premise, precisely because you'd guess that it's because of theology. That's simply not true It may not be true for you personally, but the fact remains that the purpose of the ID movement is not the way you seem to want to paint it. I fear that you have been had. If you are truly interested in unbiased scholarship, then the ID lobby are not your fellow travellers.
It's based on the notion that if humans were to seed a planet and front-load, we would almost certainly choose to front-load Metazoa and try to front-load intelligent life forms, would we not? But that's not any kind of valid reasoning, that's just bias. You are assuming that the front-loader would make something that resembles us just because that what you or I would make. You are founding your whole argument upon an unsupported assumption based upon anthropomorphic bias.
Ummm, because prokaryotes were around for about a billion years before eukaryotes came on the scene. But that doesn't mean a thing. Maybe the front-loader aimed for bacteria, got what he wanted and life has progressed on its own terms since that time, no front-loading required. Besides, modern prokaryotes haven't been around for billions of years. One could easily argue that some recently evolved eukaryote was the intended outcome. Perhaps the recently evolved nylon-eating bacteria were the intended outcome. Come to that, we could decide that blue-footed boobies were the intended outcome. Or absolutely any organism you care to name. This lack of specificity strikes me as a pretty major flaw. Mutate and Survive
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Genomicus Member (Idle past 2197 days) Posts: 852 Joined: |
But you're just asserting that. There is no reason to assume it. It's the premise of the FLE. We can draw testable predictions from it; if confirmed, it would no longer be an assumption.
It may not be true for you personally, but the fact remains that the purpose of the ID movement is not the way you seem to want to paint it. I fear that you have been had. If you are truly interested in unbiased scholarship, then the ID lobby are not your fellow travellers. I am perfectly aware that the ID movement has a religious agenda. Did I say the ID lobby were my fellow travelers? The problem, though, is that the FLE hypothesis was not proposed by the ID movement. The ID movement guys would far rather prefer intelligent intervention over front-loading, IMHO. Anyways, I'm not a part of the ID movement, I don't share their obvious (and awfully unscientific) religious agenda, so the point is...?
Maybe the front-loader aimed for bacteria, got what he wanted and life has progressed on its own terms since that time, no front-loading required. Yes, maybe it did. What predictions would you propose for this idea? You can advocate that idea if you wish; personally, based on various factors, I'm not inclined to advocate that idea (e.g., why didn't the front-loader put modern prokaryotes on earth from the start?). Edited by Genomicus, : No reason given.
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jar Member (Idle past 95 days) Posts: 34140 From: Texas!! Joined: |
When you bring in the "front loader" and present the method/model the "front loader" used, then, and only then, will FLE be worth anything more than a laugh.
AbE: And did you notice the topic title? It's a little late to claim that you are not just trying to market the good old ID con job. Edited by jar, : see AbEAnyone so limited that they can only spell a word one way is severely handicapped!
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Genomicus Member (Idle past 2197 days) Posts: 852 Joined: |
Front-loading is an ID hypothesis: intelligent design is involved. Feel free to have your laugh, jar
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jar Member (Idle past 95 days) Posts: 34140 From: Texas!! Joined: |
Oh, rest assured I am.
Did you not say:
quote: and:
quote: in Message 167? Sure sounds just like the Intelligent Design movement once again just trying to mislead folk into thinking that FLE really is not ID which everyone knows is just Creationism repackaged.Anyone so limited that they can only spell a word one way is severely handicapped!
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Granny Magda Member (Idle past 294 days) Posts: 2462 From: UK Joined: |
It's the premise of the FLE. We can draw testable predictions from it; if confirmed, it would no longer be an assumption. But there's absolutely no reason to prefer it over any other hypothesis, right?
I am perfectly aware that the ID movement has a religious agenda. Did I say the ID lobby were my fellow travelers? The problem, though, is that the FLE hypothesis was not proposed by the ID movement So whose idea was it exactly? Where does it originate?
The ID movement guys would far rather prefer intelligent intervention over front-loading, IMHO. The latter is merely a less direct version of the former.
Anyways, I'm not a part of the ID movement, I don't share their obvious (and awfully unscientific) religious agenda, so the point is...? It just seems odd that you would be so interested in this idea. It does seem to be popular within the ID community and it doesn't seem to have any traction elsewhere.
Yes, maybe it did. What predictions would you propose for this idea? Exactly the same as you cite for eukaryote front-loading; conserved sequences and such. The real problem is that the evidence that one would expect for prokaryote front-loading would not differ one iota from what you predict for eukaryote front-loading. nor would either differ in the least from what we would expect for normal evolution.
why didn't the front-loader put modern prokaryotes on earth from the start? Is that question only just occurring to you? Genomicus, we might as well ask why the "front-loader" didn't just go straight for the blue-footed boobies, day one. Why bother with any of this? As far as I can tell, the only reason to assume that metazoans were the intended outcome is pro-metazoan bias and anthropomorphism. Mutate and Survive
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Dr Adequate Member Posts: 16113 Joined: |
Well, under the FLE hypothesis, the origin of eukaryotes and Metazoa and plants and animals was not a matter of mere chance, but a matter of chance and direction. In other words, the first genomes anticipated the rise of these taxa ... Again, I'm wondering whether or not you wish to go with "genomes" or "genome"; in other words whether you're going to have common descent or not.
Chance does play a role in FLE, but so too do other factors - the initial states are what channel evolution in specified directions. But again any initial state only provides you with one specified direction as such. The residual variation found among organisms must be the result of factors external to the genome --- chance if you wish, something else if you can think of it, but certainly something.
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Dr Adequate Member Posts: 16113 Joined:
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And no, I don't think I'd particularly care for your guess about why the FLE posits this as an initial premise, precisely because you'd guess that it's because of theology. That's simply not true. It's based on the notion that if humans were to seed a planet and front-load, we would almost certainly choose to front-load Metazoa and try to front-load intelligent life forms, would we not? No, because apparently that means we'd have to wait an awful long time before we got any return on our investment, assuming that we wanted something other than a bunch of prokaryotes glooping around (and presumably that is what your Designers wanted or they wouldn't have front-loaded them to evolve into things other than prokaryotes). If you know in advance the genomes of the organisms you want to exist, then you might as well just make those organisms. So far as I can see, the only conceivable point in seeding a planet just with undistinguished blobs is as an experiment in Darwinian evolution, in which case you wouldn't front-load anything. This still presumes a willingness to wait a few billion years to see the results of this experiment, but at least there'd be some point in waiting. If you know what you want to happen, on the other hand, why not just make it happen?
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Genomicus Member (Idle past 2197 days) Posts: 852 Joined:
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You are painting the target around the bullet hole. If we had a time machine and were transported back in time to the era where the first life appeared (by whatever mechanism) I really, really doubt you could have predicted which proteins would be deeply conserved through life. Referring back to the Sharpshooter fallacy, you are arguing that the odds of the bullet hitting where it did were increased simply because the bullet hit where it did. Perhaps, but I think you'd be willing to agree that loading the first genomes with rhodopsins, globins, actins, kinesins, - or their sequence/structural homologs - that this would increase the chances of Metazoan-like life forms appearing on the scene. I am not "arguing that the odds of the bullet hitting where it did were increased simply because the bullet hit where it did." I am arguing that the odds of the bullet hitting where it did were increased by the aid of a sharpshooter, who, through the knowledge of the direction of the wind, the velocity of the bullet, etc., had a greater chance of hitting the target. In this case, the "sharpshooter" is the initial states that constrained subsequent evolution, channeling it in specified directions.
Even more importantly, it may just be happenstance that certain lineages were as successful as they were. I really doubt that if we travelled back in time that you would be able to pick which species would give rise to successful lineages. It is only thorugh hindsight that we know which lineages were the most successful. Quite right, but I think you might be viewing life through non-telic lenses. The issue here isn't if I'd be able to predict which lineages would be the most successful; the issue here is, namely, if life was front-loaded to give rise to the major taxa we see today, then what testable predictions would this produce?
This is a perfect example of the Sharpshooter fallacy. I see no reason why the evolution of animals requires cilia. Yes, modern metazoans do require cilia, but there is no fundamental physical law that requires ambulatory organisms to have cilia. It seems to me that it is entirely happenstance that cilia became an important function in the lineage that gave rise to modern metazoa. Other proteins could have evolved just as much importance, but they didn't. Again, you're looking at life with non-telic lenses. I think you would agree that the type of animal life that was "chosen" by Nature requires cilia to exist. Thus, if the front-loading designers wished to front-load the type of animal life that live on our planet, they'd have to front-load cilia. If they chose some other animal life forms, they'd probably have to use another type of molecular machine. But, if FLE has occurred, it is probably our type of animal life that the front-loading designers were aiming for, and so under the FLE hypothesis, cilia was front-loaded. And this results in the testable prediction I described in my second essay, a prediction which, incidentally, does differ from the non-telelological model.
Let's look at the game Jenga. IMHO, it is a great analogy for biological interdependence. As you move more and more blocks to the top of the stack you will find that certain blocks are absolutely vital to keep the stack upright. However, there is no way you could have predicted ahead of time which blocks those would be. These vital blocks only become vital as time moves forward. No one had to stack the deck to make these blocks vital. It just happens. Evolution is the same way. Certain proteins will start towards the "top of the stack" and are not a vital function. However, as more and more functions become dependent on that function (i.e. more blocks are stacked on top of it) it becomes a vital function. You want to say that this requires foresight and planning, but I see no reason why it does and you have offered no evidence as to why it would. No, I'm not saying that at all. Evolution can make proteins necessary over deep-time, without the input of foresight and planning. I'm saying that, under the FLE hypothesis, we can glean several testable predictions that do differ from the non-teleological model. I'm really not quite sure where in my essay you got the inspiration to go on what seems to me to be a bit of a tangent, IMHO. I described two predictions made by the FLE hypothesis, one regarding levels of sequence conservation in prokaryotic homologs of cilia, and the other regarding deep homology and proteins in eukaryotes. These predictions are not made by conventional theory. Edited by Genomicus, : No reason given. Edited by Genomicus, : No reason given.
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Genomicus Member (Idle past 2197 days) Posts: 852 Joined: |
But there's absolutely no reason to prefer it over any other hypothesis, right? That depends on the amount of evidence the other hypotheses have.
So whose idea was it exactly? Where does it originate? Mike Gene formulated the front-loading hypothesis. Here's how much he's part of the ID movement: http://www.designinference.com/...ents/2002.07.Mike_Gene.htm.
Exactly the same as you cite for eukaryote front-loading; conserved sequences and such. The real problem is that the evidence that one would expect for prokaryote front-loading would not differ one iota from what you predict for eukaryote front-loading. Actually, the predictions would differ. If modern prokaryotes were front-loaded from previous prokaryotes, and eukaryotes were not front-loaded, we would not predict that prokaryotic homologs of protein components of the eukaryotic flagellum would be more highly conserved in sequence identity than the average prokaryotic protein, for example.
nor would either differ in the least from what we would expect for normal evolution. I've already responded to this claim, but here it is again:
It is important for a hypothesis to make testable predictions. Here, I will try to briefly describe how the FLE hypothesis makes predictions that are not made by conventional theory. Before beginning, however, I would like to point out that, in this thread, I do not intend to discuss in depth the issue of whether some of these predictions have, in fact, been confirmed. In this thread, I am primarily interested in discussing if these predictions differ from those generated by conventional theory. Let me begin with a prediction concerning the origin of molecular machines like cilia. Intra-flagellar transport (IFT) particles are involved in ciliary function in most eukaryotes. These proteins contribute to ciliary function, and any eukaryotes that lack these IFT proteins — such as Plasmodium -- are probably degenerate cilia and do not represent the structure of the last cilia common ancestor. The point is this: under the non-teleological framework, co-option events are primarily responsible for the origin of this motility organelle and its IFT proteins. Under this model, random co-option events of proteins in the cell resulted in the functional association of different proteins, which would have been preserved by natural selection — and over time, through repeating this step, finally a cilium arose. This is, in essence, the non-teleological hypothesis for the origin of the eukaryotic flagellum. Given that the existence of Metazoa seems to require the existence of cilia, under the FLE model, cilia were front-loaded. How would cilia be front-loaded? The FLE hypothesis is only at its beginning stages, so one should not expect, at the present moment, a rigorous FLE model for the origin of the cilium. However, I can offer a cursory model for the FLE origin of the cilium. In this model, the first genomes would be designed with components that would later be used by the cilium. In other words, homologs of the core, necessary IFT proteins would be designed into the first genomes. They’d be given a function, such that their basic 3D shape is conserved over deep-time. If they were given a function where their 3D shape would be substantially changed over deep-time, then the front-loading designer couldn’t possibly hope that when these proteins associated, their shapes would complement each other correctly such that a cilium could arise. From here, we can develop our FLE prediction. The non-telic hypothesis for the origin of the cilium does not require or predict that the prokaryotic homologs of IFT proteins be well-conserved in sequence identity. In fact, it’s certainly possible that the non-telic hypothesis predicts that most of the prokaryotic homologs of the core IFT proteins will be loosely conserved in sequence identity: a protein that is not under stringent functional constraints will be more likely to be co-opted into a novel role by chance without being deleterious. For example, H4 histone is one of the most highly conserved proteins in eukaryotes. To me, at least, it seems that it would be much more likely that if H4 histone was duplicated and then co-opted into an entirely novel function a non-adaptive effect would occur than if a fibrinopeptide, for example (which are not at all highly conserved), were co-opted into this novel role. This would be an interesting line of research, but I don’t intend to explore this argument further, because the fact remains: the non-telic hypothesis for the origin of the cilium does not require or predict that the prokaryotic homologs of core IFT proteins be well-conserved in sequence identity, while the FLE hypothesis for the origin of the cilium predicts that the prokaryotic homologs of core IFT proteins would be well-conserved in sequence identity, more so than the average prokaryotic protein. This is a testable prediction: we would need to find a prokaryotic homolog of a core IFT protein, and then conduct pairwise comparisons of that IFT homolog with its prokaryotic orthologs, and check its degree of sequence conservation. There is nothing in the non-telic hypothesis that predicts this hypothetical prokaryotic homolog will be highly conserved in sequence identity, more so than the average prokaryotic protein. You will not find anything like this prediction in the scientific literature. IMHO, this is an exclusively teleological/FLE prediction. Deep Homology and Front-loadingI argue that the FLH predicts that proteins of major importance in eukaryotes and advanced multi-cellular life forms (e.g., animals, plants) will share deep homology with proteins in prokaryotes. I have discussed this prediction with various critics of the FLH, and the most common objection seems to be that non-teleological evolution also makes this prediction. I disagree, so let me explain. Life seems to require a minimum of about 250 genes (Koonin, Eugene V. How Many Genes Can Make a Cell: The Minimal-Gene-Set Concept, 2002. Annual Reviews Collection, NCBI) — a proto-cell would not require that many genes. Thus, it would be perfectly acceptable, under the non-teleological model, that the last common ancestor of all life forms had approximately 250 genes, add or take a few. From this small genome, gene duplication events would have occurred, subsequently followed with mutations in the new genes, would lead to a novel protein. Over time, then, and through gene and genome duplication/random mutation, this small genome would evolve into larger genomes. This model is perfectly acceptable with the non-teleological hypothesis, and the non-teleological hypothesis does not predict otherwise. However, this model — where a minimum genome gradually evolves into the biological complexity we see today, through gene duplication, genome duplication, natural selection, and random mutation — is not compatible with the front-loading hypothesis. This is because front-loading requires that the first genomes have genes that would be used by later, more complex life forms. Of the 250 or so genes required by life, none of them could encode proteins that would be used later in multicellular life forms (excluding the proteins that are necessary to all life forms). A front-loading designer couldn’t possibly hope to stack the deck in favor of the appearance of plants and animals, for example, by starting out with a minimal genome. Look at it this way. With a minimal genome of 250 genes that are involved in metabolism, transcription, translation, replication, etc., evolution could tinker with that genome in any way imaginable, so that you couldn’t really front-load anything at all with a minimal genome. You couldn’t anticipate the rise of animals and plants. Such a genome would not shape subsequent evolution. If the last common ancestor of all life forms had a minimal genome, and if you ran the tape of life back, and then played it again, a totally different course of evolution would result. But if you loaded LUCA with genes that could be used by animals and plants, you could predict that something analogous to animals and plants would arise. If you loaded this genome with hemoglobin, rhodopsin, tubulin, actin, epidermal growth factors, etc. — or homologs of these proteins — something analogous to animal life forms would probably result over deep-time. Given that you couldn’t really front-load anything with a minimal genome consisting of about 250 genes, under the front-loading hypothesis, it is necessary that LUCA contain unnecessary (but beneficial) genes that would later be exploited by more complex life forms. Non-teleological evolution does not require this. It has no goal, unlike front-loading. It tinkers with what is there — and if a minimal genome was all that was there, it would tinker around, eventually producing endless forms most beautiful as Darwin so famously put it. On the other hand, front-loading is goal-oriented: a minimal genome does not allow one to plan the origin of specific biological objectives. Thus, under the front-loading hypothesis, we would predict that important proteins in eukaryotes, animals, and plants will share deep homology with unnecessary but functional proteins in prokaryotes. Non-teleological evolution does not predict this. Non-teleological evolution could explain that observation, but it does not predict this. And this is the important point to understand. There is nothing in non-teleological evolution that requires multi-cellular proteins to share deep homology with unnecessary prokaryotic proteins — but front-loading demands this. There is nothing in non-teleological evolution that requires that LUCA have a genome larger than the minimum genome size — but for front-loading to occur, this must be the case. I conclude, then, that this prediction is made by the front-loading hypothesis, but it is not made by non-teleological evolution, and so front-loading is certainly testable. That said:
Is that question only just occurring to you? Genomicus, we might as well ask why the "front-loader" didn't just go straight for the blue-footed boobies, day one. Why bother with any of this? Prokaryotes are far more survivable, and would be far more likely to survive on the early, hostile earth, than eukaryotes. Sure, the front-loading designers could have dropped a population of cows right from the start, but this would fail miserably. You need a whole biosphere for the existence of complex life forms. That's the answer to your question; but IMHO my argument does not answer my question to you of why the FL designers wouldn't seed the earth with modern prokaryotes in the first place - according to this alternative FL hypothesis you're "advocating." Edited by Genomicus, : No reason given.
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Tangle Member Posts: 9581 From: UK Joined: Member Rating: 6.5 |
You ducked my point. Fully loaded dice with throw a 6 every time. But any unfair loading of the dice will ensure certainty of outcome (more 6s than any other number) if rolled often enough.
How many times are you allowing your front loaded genome(s) to be rolled? Assuming billions of years, that would be multiple billions of rolls.Life, don't talk to me about life - Marvin the Paranoid Android
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Genomicus Member (Idle past 2197 days) Posts: 852 Joined: |
How many times are you allowing your front loaded genome(s) to be rolled? Assuming billions of years, that would be multiple billions of rolls. I question the relevance of the dice analogy. Take a deck of cards, load it with aces, such that, say, 30% of the deck consists of aces. You'll be far more likely to get a hand of four aces than if you had not tampered with the deck of cards. That's front-loading, in a nutshell.
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bluegenes Member (Idle past 2733 days) Posts: 3119 From: U.K. Joined: |
Genomicus quoting Butler et al. 2009 writes: "The extreme optimization of the genetic code therefore strongly supports the idea that the genetic code evolved from a communal state of life prior to the last universal common ancestor." Butler seems to agree with the (non-telic) hypothesis put forward by Carl Woese. That is that the standard code may have evolved in an early epoch of communal life prior to the LUCA in which HGT played an important role. That's certainly possible. What we can say at the moment is that we know very little about how it evolved. That, I'm sure you understand, is not a reason to stick unparsimonious intelligent designers into the gaps in our knowledge.
Genomicus writes: An extremely optimized genetic code, like the standard genetic code, wouldn't seem to be terribly advantageous to unicellular organisms, in contrast to less optimized genetic codes. Radical substitutions would be far more likely to be non-deleterious in unicellular organisms than in complex, multi-cellular organisms. In fact, a less optimized code might be more advantageous for unicellular organisms, in one sense: it would accelerate the rate of protein evolution. That's rather vague. Why do unicellular organisms need to evolve at a faster rate? To what or whose objective? It would only be our speculative front-loaders who might have an objective. If so, why didn't they give prokaryotes "sub-optimal" codes? Why not give them lots of different ones in order to increase their chances of reaching their objective rapidly? Also, I don't understand these front-loaders. If the objective of the seeding of a planet is plants and animals, then it would make sense to start off with eukaryotes (or some equivalent) somewhere in the original mix, as I've suggested before. It would make sense to engineer something like the mitochondria into some cells, because such a thing would be required to "power" the more complex multi-cellular life forms. Seeding a planet only with cells that do not have such a thing means relying on a chance endosymbiotic event to produce it. If plants and animals were the objective, why not maximise the probability of getting them?
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Tangle Member Posts: 9581 From: UK Joined: Member Rating: 6.5 |
Genomicus writes: I question the relevance of the dice analogy. Take a deck of cards, Ok, forget the dice, use your card deck analogy
load it with aces, such that, say, 30% of the deck consists of aces. You'll be far more likely to get a hand of four aces than if you had not tampered with the deck of cards. That's front-loading, in a nutshell. Why are you assuming that the deck is only cut once? If there's a 30% chance of getting an ace in the first cut, there's a near certainty of getting an ace in 10 attempts. Evolution cuts the deck billions of times......Life, don't talk to me about life - Marvin the Paranoid Android
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Perdition Member (Idle past 3494 days) Posts: 1593 From: Wisconsin Joined: |
as a layman i find your description of FLt very good and useful Good.
If we accept Lamarckism That's a very big if.
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