Oolon Colluphid

Yeah, very loosly described thus. It’s actually defined, though, as a change in allele frequency in a population over time. Discuss it at tabloid newspaper level if you want, but you won’t be talking about the science of it.
I really, really must get my website going. I’ll have a bunch of standard replies, that we can just cut and paste... because I’ve lost track of the number of times I’ve written the same things over and over.

Okay, it’s a tautology. Well apart from ‘survival of the fittest’ being a very loose description, as John Maynard Smith has noted, any two lines of algebra contain a tautology!

If I say that a train travelling at 60mph will arrive at station B from station A in half the time of one travelling at 30mph, the fact that this is a tautology makes not a blind bit of difference to the validity of the statement, nor to the usefulness of the information thus tautologically encoded.

TTFN, Oolon

Oolon Colluphid

Herbert Spencer, actually .

Oolon

pz

Yes. And disliked by Darwin.

MrDarwin

Hmmm, disliked so much that he included it in the 6th Edition of the Origin of Species? From chapter 4:

In fact, this chapter in the 6th edition uses the phrase "survival of the fittest" no fewer than 7 times.

Peez

Evolution does not require the cooperation of a deity. The theory of evolution provides a scientific explanation for how evolution occurred, but that is quite beside the point that it did occur. The evidence clearly and unambiguously indicates that living things have evolved by descent with modification from common ancestors. It could have occurred by divine interventions, it could have occurred by alien interference, it could have occurred by some as yet unknown scientific process, but it is a scientific fact that it occurred regardless. Please keep in mind that "evolution" refers to a process, a fact, and a theory.My point was that you have made this judgement without knowledge. Of course we cannot all be experts in everything, but if physicists the world over study physics and come to the conclusion that it is impossible for matter to move at the speed of light, even if I don't personally understand it, and even if it runs contrary to what my "common sense" tells me, I would not be able to state that I do not believe it. I might remain skeptical on some level, but then I am skeptical of the existence of the universe on some level.In other words: "what if there is a different scenario?" I don't care about a different scenario, I presented one to illustrate the point that it is premature to come to the decision that you do not believe something when you don't even know what it is.The eye is a structure, so why did this seem to be a problem for you?When you can explain exactly what those are, and how they work, then we can address the issues of how they came to be. Meanwhile, you seem to be using a "god of the gaps" argument.For the evolution of emotions? It is impossible to say until we understand what emotions are.If by "proved" you mean ‘established with complete certainty,' then nothing is ever "proved" in science. Even the existence of the universe is not "proved" in that sense. On the other hand, if by "proved" you mean ‘established by so much evidence that it is accepted as true by the scientific community' (like heliocentrism, the gravitational attraction between masses, the atomic nature of elements, etc.), then common descent certainly is "proved." From page 11 of Evolutionary Biology, Third Edition (Douglas J. Futuyma, 1998, Sinauer):No competent scientist questions that the earth orbits the sun, that life has evolved from a common ancestor, or that elements are made up of atoms.We can argue semantics, but the common descent of organisms is as well established as heliocentrism, atoms, gravity, etc. In any event, the "objections" that you have presented here have nothing to do with the fact of evolution, they are all addressed to the theory of evolution.I do not understand what you are getting at here. First, you questioned whether there was any advantage to beneficial mutations, then I explained that by definition there must be, and you just say "no kidding" and make reference to some problem with a definition. If you have some definition of "beneficial" or "advantage" that is different from those used by biologists, then perhaps you are not understanding what we mean when we say "beneficial mutation." Am I on the right track here?It is as well-defined as any word that I know, and better-defined than most. Of course, I am talking about the term as biologists use it. From Futuyma:Put simply, it is reproductive rate.Darwin used "fitness" in a different way than we do today, and no evolutionary biologist today calls evolution "the survival of the fittest." That being said, one can say that the fastest runner wins the race: this is a tautology but no less true for it. Also, bear in mind that "the survival of the fittest" refers to the theory of evolution, not the fact of evolution. See here for a more complete discussion.No, this is your misunderstanding of the theory, as explained.Actually, you do not know what I know. I have already defined fitness, and I can simply define "beneficial" as something that confers an increase in fitness to an organism under particular conditions.I am not sure what you mean by "proven" in this context. I explained how a cell that does not respond to light could become a cell which does respond to light through a simple, small change in one protein. Since then I have done my best to answer questions about how proteins work, etc., but I did not see any problems raised with the model. If I missed something, please point it out.[quote][b]Specifically, you have not presented any explanation of how this could occur:I see. Just to be straight, are you asking me to now explain how the nervous system evolved as well?No, we were asked to explain how a photoreceptor could have evolved. Strictly speaking, I suppose that this could include explaining the Big Bang, all of physics and chemistry, star and planet formation, abiogenesis, the evolution of eukaryotic cells and organelles, the evolution of multicellularity, and the evolution of all body systems. That would be excessive, of course. When you asked about the evolution of the eye, I took it to mean how the eye specifically evolved, and that I could defer various other explanations for the time being. I simply do not have the time to instruct you in every detail of the evolution of every part of every living system on the planet, even if I did know them all. On the other hand, if we stay focussed on the evolution of a specific example, like the eye, then perhaps we can show you how something that you couldn't believe evolve could have evolved. The general message would be that other things that you believed couldn't have evolved might indeed have evolved, without having to spend years going through each and every one. The other problem is that if we keep being distracted by discussions of other topics, it will be much more difficult for you (and I) to follow the topic.You are assuming that it would confer "absolutely no advantage," without any reason. Perhaps you are assuming that the organism requires a nervous system to respond, this is not true. I gave one example of "an aquatic unicellular organism that responds to heat by moving up in the water," here is another:

A simple organism similar to a hydra (the coelenterate, not the mythical reptilian creature) responds to a certain chemical by shrinking away from it (the chemical is one given off by another organism that might eat the hydroid). A mutant hydroid has a changed protein in the chemoreceptor: if still responds to the same chemical when folded properly, but will only fold properly when there is light on it. In the absence of light, the protein folds in a different way that causes it to respond even without the chemical present. This would be a disadvantage if the hydroid lived in the dark all the time, but in the light this could confer an advantage: it makes the hydroid shrink away from any shadow during the day (from, e.g., a predator).As explained, the organism does not even have to have a nervous system, and if it did the proteins are already there for something else and need only be modified.Actually many genes do stay in the genome without any benefit to the organism, but that is not necessary here. As explained, the benefit may be gained immediately.Actually "5% of an eye" is very useful to an organism that has no eye otherwise. In fact, there are many living organisms that have "5% of an eye" and find it very useful.As I have explained, if the gene confers no benefit then it is not favoured by natural selection and therefore might not spread in the population. However, if you wish another example:

Let us keep it simple: a population of hydroid organisms that are haploid (one allele/gene per organisms for a particular trait). There are 100 organisms in the population. Every summer the individuals in this population reproduce and die. In the fall many are killed by predators, then over the winter only 100 will survive, the rest will be killed. Which ones are killed over the winter is completely random. All individuals that survive the winter will produce 10 offspring. To start, half of the population (50) has a gene (A) that gives them no ability to respond to light (and so 50% of them are killed by predators), the other half (50) has a gene (B) that gives them the ability to respond to light (and so 48% of them are killed by predators).

The first summer the population swells from 100 to 1,000 (500 with gene A and 500 with gene B). That fall predators kill 490 of them (250 with gene A and 240 with gene B), leaving 510. The following winter, 410 will die completely at random, which means that about 19.6% will survive. Well, there are 250 with gene A and 260 with gene B, so if survival is random then about 19.6% of 250 with gene A will survive and about 19.6% of 260 with gene B will survive: about 49 with gene A and 51 with gene B.

The second summer the population swells from 100 to 1,000 again (490 with gene A and 510 with gene B). That fall predators kill 490 of them (245 with gene A and 245 with gene B), leaving 510. The following winter, 410 will die completely at random, which means that again about 19.6% will survive. There are now 245 with gene A and 265 with gene B, so about 19.6% of 245 with gene A will survive and about 19.6% of 265 with gene B will survive: about 48 with gene A and 52 with gene B.

The third summer the population grows to 1,000, predators kill 490, then about 19.6% survive leaving 47 with gene A and 53 with gene B.

Evolution is already happening, the B gene is becoming more common in the population even through winter mortality is entirely random.As I said, genes can and do spread by "shear luck" (look up genetic drift), but it is quite possible for a gene that allows an organism to respond to light to be favoured by natural selection and so to evolve as an adaptation (as described above).Are you suggesting that cats evolved tails from a cat-like ancestor with no tail?Before I can "share the nuances of (the) theory," you need to understand just what a scientific theory is, and how common descent is not a theory.It doesn't worry me at all. Truth be told, I don't expect you to.I am bothered by what I see as evasive tactics, though I presume they are not intentionally so.No, this is not true. "Evolution" (you need to be more specific here, I assume that you mean the theory of evolution) is not supposed to explain everything. If you can find something that it cannot explain, then you have found something that it cannot explain. The things that it can explain remain. Also, don't confuse what I cannot explain with what the theory of evolution cannot explain.Yes, this is true of rhodopsin, and every other protein that is embedded in a plasma membrane. As I "made up" the putative precursor, then you could say that I "made up" the fact that it had the non-polar region, but of course if it was a protein already embedded in the membrane (like one that opens in response to a chemical or to heat) then it had to have such a region.Your answers don't inspire much either. I understand that I am using some terms that are new to you, and concepts with which you are unfamiliar, but at least some of your errors seem to stem from just not reading the posts carefully.In the example I gave, the organism responded to heat. A mutation resulted in the protein that used to respond to heat now responding to heat or light. Thus, light affects the organism just as heat does. The only way that the organism can sense heat will respond just the same to heat and to light. I don't know how much clearer I can be.I have never claimed that there is any advantage to "a light sensitive molecule which the organism can't respond to or incorporate into it's actions in any way," so it seems a rather pointless question to address.You don't have to be very resiliant, as a single-celled organism. Exactly how close to a lightning strike would an amoeba have to be to be killed? I don't know either. Just for the sake of argument, let's say 100 m (a gross overestimate in my view). Just what are the odds that a bolt of lightning will strike a given 100 m diametre area within a month? Not much. Of course, in one month we could go from one to one billion amoebas if they divide only once each day. Now, if all those amoebas would just stay put long enough for lightning to strike. Even that assumes that they all stay at the water's surface.Even if these phenomena occurred every week, they would be unlikely to kill off all the organisms at the surface, but I note that you did not comment on what would happen deep under the ocean's surface, where these critters probably evolved. Anyhow, I see no problem with early evolution, but if you wish to posit that one or more gods created the earliest life form in high nimbers, that imposes no problems for evolution.

Peez

luvluv

Peez:

Okay, that would be possible for me to accept, but then I would also add that incrementalism could very well go out the window on most of the above views.

That would eliminate my strongest objections to evolution: 1) That the beneficial mutations would show up unguided in the first place, 2) That the mutations are necessarily incremental (mostly because no one can find a mechanism for larger changes) and 3) Such incremental mutations which confer no advantage inexplicably still allow it's possesor to outreproduce it's fellows.

If there were a concious mind guiding all of this, it is entirely plausible to me. On a certain level, if this were conceded by all scientists, I would have no debate with evolution per se only purely naturalistic evolution.

However, I feel confident that precisely no one else in this discussion feels the way that you do on the subject, and the masters of the field would find the notion nauseating.

Actually, you would be able to do just that.

Do you mean you wouldn't feel qualified to say you don't believe it?

I believe I know enough to say I don't believe in evolution based on the objections I've raised. I'm not a total idiot, I wasn't raised in a barn. I took AP level courses in biology in high school (though I admit it is all a blur now) and believe it or not I even managed to squeeze in a few years in college.

Now, I do not have a degree in biology or anything, but I believe I understand enough about evolution to say that I don't believe in the process of evolution. My objection is not so much common descent but with UNGUIDED common descent. I have a problem with the notion of mutation and selection being capable of producing the complexity of life we see UNGUIDED.

I've said REPEATEDLY on this forum that I am not a special creationist. I do not believe in the special creation of each species. But I equally do not believe that the mechanism of blind mutation and natural selection can accomplish the diversity we see on this planet. I can believe all of it except the unguided part.

My point was that you chose a bad example which really illuminated precisely nothing for me.

Yes, I suppose if there were cars driving randomly towards Eden and if there were humans in the cars communicating by radio, or if the cars had been programmed by humans to communicate by radio, and if those cars were programmed by humans to seek out Eden in random steps, then perhaps the car could one day get to Eden with the aid of the constant intervention of human intelligence.

That doesn't really help explain how genes that don't confer any advantage come to dominate a poplulation, which is what I asked about.

It's a more complicated structure with soft, interconnected parts, which must be hooked into a nervous system which must then develop the ability to process and use the information given it by the eye. Basically it's orders of magnitude more complex than a bone, in terms of what it needs to function. Thus, it is harder for me to believe.

1) I wasn't asking you to explain them, I was simply informing you of some of the reasons why I find evolution hard to believe.

2) I am not advocating "god of the gaps." I am advocating "intelligence of the gaps." Whether the intelligence belongs to God or some alien race, it makes me no difference in the context of this conversation. Any appeal to intelligence has always been more plausible to me than an appeal simply to random mutations and natural selection.

Okay, but to be clear I am simply questioning the mechanism, and whether chance and selection alone can accomplish much of anything. Common ancestry alone doesn't bother me that much.

My point is that all this amounts to is saying that what ever is still around must have been better at reproducing than what isn't around anymore. It's still the survival of what has survived.

Okay, well then I don't believe in the theory of evolution.

No, so far as I can tell, you have described how a cell could evolve one molecule which is light-sensitive.

You said nothing of how this light-sensitive molecule could give this cell the ability to RESPOND to light. You might be able to do so, but you haven't done it yet.

When I've asked, you just say I'm avoiding the question. Excuse me, I am not.

I expressly stated BEFORE YOU ENTERED THE CONVERSATION, that part of my objection to the evolution of something like the first eye (or light sensitive spot, or whatever) is that not only did the structure have to come into existence, but the nervous system had to intergrate with that structure in some kind of way that enabled the organism to respond in a beneficial way to the new stimulus. You are acting as if I added this objection later in the conversation, but this was my position from the begining.

If you don't want to take the time to dismantle all my objections then don't. But please don't attempt to address half of them and then complain that I am not playing fair when I ask you to address the other half.

No.

Let's do a quick thought experiment.

Pluck your eye from your head.

Now, notice that while the eye is probably morphologically perfect (it has the perfect shape and stucture to do it's job), you can't see a bloody thing out of it.

Why?

Because it's not hooked to your nervous system.

Therefore, you haven't explained the eye until you've explained how not only this lucky molecule happened upon our brave little cell, but how a totally unrelated mutation occured which allowed this molecule to actually send a stimulus to the rest of this cell which would help it to respond.

Understand, I am not talking about 5% of a human eye.

I am talking about 5% of whatever functionality an organism has. That is (are you listening Oolon ?) 5% of a light spot, or a photocell, or whatever the smallest increment is of whatever light-sensitive structure we are talking about.

There is no reason to believe, and probably good reason to disbelieve, that in it's first iterations the "eye" or "light sensitive moleucle" offered ANY ADVANTAGE WHATSOEVER.

And if Dawkins and his camp are right, then we have to explain how such a useless appendage (and 5% of any "eye-like organ" would be a useless appendage) managed to stick around until it got to making itself into an eye. I can't explain it except by the action of intelligence, perhaps in the form of purposeful breeding.

Look, this is not complicated.

What I'm asking is how does possesing a light-sensitive molecule, which you cannot respond to AT ALL give you an advantage over not having a light sensitive molecule.

In either case, you cannot respond to the presence of light.

So do a thought experiment in which half the population has a light-sensitive molecule and yet no ability to respond to light, and the other half has no light-sensitive molecule and no ability to respond to light.

Actually, this is unreasonably stacking the deck, since the light-sensitive molecule possesor is the mutation, and the individuals without the light-sensitive molecule are the "norm."

So explain how ONE organism with a light-sensitive molecule and no ability to respond to light will REPLACE 99 organisms with no light-sensitive molecule and no ability to respond to light.

That, for the umpteenth time, was my question.

No, I already said I was using this as an example to prove a point, and that I was not saying this was what actually happened.

But back then I was under the impression that you were... you know... reading my posts.

Main difference being, I'm not a biology teacher.

Mr. Pot, have you met Mr. Kettle?

Oolon Colluphid

As the captain of the road prison says in Cool Hand Luke: “What we’ve got here is... failure to communicate.”

Now, it could be that both luvluv and Peez are being let down by their communications skills. However, as Clive James has noted, unclear writing isn’t a result of unclear thinking, it is unclear thinking. And as I know too well, it is hard to think clearly about a subject one lacks knowledge of.

So the thing is, Peez actually does know what he’s talking about (it being what he does for a living), whereas similar knowledge on luvluv’s part is at least open to question. So the balance of probabilities is that it is luvluv who needs to pay greater attention to the words on the screen.

That’s as unbiased as I can put it. Now for a little bias: it seems to me that Peez has gone to some lengths to try and figure out what luvluv is trying to say, whereas luvluv keeps repeating himself (eg “That, for the umpteenth time, was my question”), because he’s not understanding the answers given. Which implies he doesn’t understand his own questions.

All of which is to say: luvluv, the pot, is calling the refrigerator ‘black’.

TTFN, Oolon

Oolon Colluphid

You still sound like you are taking something now, subtracting most of it, and then pointing out that it wouldn’t work. Well, duh!

But to put it as ‘five percent of an eye’ is to look at it retrospectively: it suggests that 95% is missing. But at the time, it would have been 1% better than the 4% eye the competitors had. And those eyes were 1% better than their great-grandparents’ 3% eye. And so on. In the kingdom of the blind, the very very partially sighted creature is king... till something better comes along.

And specifically, there are in nature a whole panoply of critters with eyes that aren’t as ‘complete’ as ours, ranging from a simple spot of pigment to groups of spots to sheets of cells to cups, and so on. And they seem to get by just fine.
Is it worth it?
What, you think it’s impossible for a protein to be coloured? For a photon striking it to affect it (that’s what being ‘coloured’ means, yeah?)? For that effect to have another effect elsewhere? Please be more specific -- where’s the problem (other than in your own mind)?
Why? Please explain why there is no reason to believe this, and please give some of these good reasons to disbelieve it.
Because at each stage, from simple light detection on, an advantage was conferred. Note that the first ‘eyes’ didn’t have to be used for sight: that could be a co-opted by-product, a ‘spandrel’ later taken up and adapted.

Put it this way: plants don’t see, yet they ‘detect light’ rather well, in fact they rely on it. They detect it with cell organelles called chloroplasts. And they used to be bacteria.

At first, it might just be a coloured chemical, coloured just because that’s how it is. (Blood, for instance, isn’t red because red’s a nice colour, but because of the properties of iron and haemoglobin.) It could stick around by being useful in some other way than for seeing with. But then, in an environment where light detection could matter, it being like that could then be an advantage. That is, something that selection could act upon.
5% of an eye-like organ clearly isn’t useless, since there are creatures that have such things alive today; but 5% of an eye equally clearly is, because that’s looking retrospectively at it.

And -- perhaps you missed this in my previous post? -- there are creatures alive today that do indeed have 5% of an eye. That is, they have ‘proper’ eyes, like other similar but sighted creatures have, but with important parts missing and / or reduced to the point of not working.
Rather than us having to explain how something that might be useful could “stick around until it got to making itself into an eye”, perhaps you might explain how such useless appendages (and 5% of a proper, high-tech eye would be a useless appendage) as the eyes of marsupial moles managed to get given to them by an intelligent creator.

Please explain how giving eyes that do not work to creatures that do not need eyes at all suggests the creator had ANY INTELLIGENCE WHATSOEVER.

TTFN, Oolon

MrDarwin

luvluv, two things about mutations: we know that they happen, but in general we don't know precisely how and why. So although I consider it extremely improbable, it's possible that there's the invisible hand of some supernatural entity--or for that matter, space aliens using some superior technology we can't detect--reaching into cells and tweaking the molecules to cause mutation. Maybe every beneficial mutation arose in this way, and that's what has allowed evolution to occur.

But here's the kicker: mutations happen all the time. They are extremely common and they are of all kinds: beneficial, harmful, and neutral (although as I pointed out earlier, which is which can depend on the organism's environment). This is something we know, something we observe, something we can test.

Now, in the absence of knowing the precise how and why of mutations, can you tell us how to distinguish between these three (of many) different possibilities--natural, supernatural, or alien influence, or even any combination of the above--for the mechanism of mutation? Given what we know about mutations, there is no reason whatsoever to think they happen by anything other than chance--that there is no consciousness of any kind guiding them. Again I have to ask, what reason would make us think otherwise?

MrDarwin

luvluv, in general what you're asking about is how we go from DNA to molecules to behavior--and this is a field that is still very poorly known. I'm not sure we'll ever be able to give you the answers you're looking for, simply because they haven't been discovered (yet). So this discussion may very well continue to go in circles. I don't think you're asking unreasonable questions, but I think you may have unreasonable expections about our ability to answer all of them--or are unreasonable concluding that, if we can't satisfactorily answers your questions, the answer by default must be a supernatural one.

I'm not sure what basis you have to disbelieve this--but it may not even matter. A light-sensitive pigment somehow came into being; whether this pigment was initially beneficial, harmful, or entirely neutral, the cell survived and it (or its descendants) somehow came to "recognize" this pigment and alter its behavior upon that recognition. Since there is still much we don't know about how chemical processes are translated into behaviors, I realize you are going to find this unsatisfactory.

But can we take a slightly different approach? It's been pointed out that the first light sensitive molecules may have been used for something else entirely. In other words, they were already light-sensitive (because it is a physical characteristic of the chemical) but that light sensitivity made no difference whatsoever. Perhaps they somehow acquired an additional function on top of the original one as a result of this light sensitivity, and the original function was eventually lost. (Yes, I know that "somehow" is where you're getting stuck.) Or perhaps the light-sensitive pigment resulted from a mutation altering the structure of a molecule that already existed in the cell, which produced one behavior, but in its new altered form produced either the same behavior in response to a different stimulus, or produced a different behavior altogether. The point is, a mutation does not necessarily result in the cell ceasing to function. A mutation can have no effect whatsoever, or a mutation can alter the chemistry of a cell, and thus the behavior of that cell.

I don't find this line of reasoning so hard to believe because we can already observe how mutations alter the behavior (and here I'm using the term "behavior" rather loosely) of single-celled organisms that we rear in a laboratory setting. Mutations that result in a change in a chemical in a cell result in a change in the cell's behavior.We don't necessarily know how or why that mutation resulted in that change, but we know that it happened because we can observe and measure it. It's not magic, it's simply something we don't fully understand yet.

Now, how might we test this? I have two questions which I'm hoping somebody else can answer because I suspect it's already been investigated:

First, is rhodopsin (or any other light-sensitive pigment) used for anything else in the cell? This would indicate that it may have already existed before being used in light detection--in other words, the origin of the molecular itself is irrelevant, and we need to examine how that molecule results in behavior.

Secondly, are there molecules very similar to rhodopsin (or other light-sensitive pigments) that are used for other things in the cell? Better yet, are these similar molecules likewise involved in the behavior of the cell? This would suggest that a simple mutation changed the function of such a molecule, with a concomitant change in the cell's behavior (or rather a shift from responding to one kind of stimulus to responding to a different kind of stimulus).

(Edited to add that a quick google search turned up this abstract:
Evolution of the archaeal rhodopsins: evolution rate changes by gene duplication and functional differentiation
This certainly supports my idea that the ability to detect and respond to light originated long before the evolution of multicellular organisms, and suggests precisely some of the things I was wondering about above.)

Edited again to add a link to a very interesting interview I came across regarding eye evolution: Walter Gehring: Master Control Genes and the Evolution of the Eye

From the interview: