Problems with Mutation and the Evolution of the Sexes

Even more amusing is 150 years later, thousands of scientists, hundreds of textbooks, millions of papers and nobody ever thought that sterile mutants cant breed! Your awful smart to have caught that one. Its over now. With something so incredibly subtle as what you have just suggested finally coming to light... its implications are stunning.

Hi CTD,The responses you've drawn so far have put more effort into ridicule than explanation, so in case it isn't painfully obvious by now, let me explain why this drew the responses it did: Even before Darwin it was understood that only those able to reproduce can contribute to the next generation. It is a fundamental tenet of evolution that mutations, which can range from favorable to neutral to unfavorable, can affect differential reproductive success, and that mutations preventing reproduction, being especially unfavorable, will quickly be removed from the gene pool.In other words, you accused evolution of not being aware of something that is actually one of its defining characteristics.Those like you and Lyston who have no idea what evolution actually says can convince others equally ignorant that evolution has some flaw and then cast ridicule at the strawman you've built. This is often called lying for Christ, but I think you two honestly have no idea about evolution, so it would be more accurate to call this ignorance for Christ.Lyston's problems with mutations are mistaken because his understanding of evolution is fatally flawed beyond belief, as apparently is your own. The irony is that the wise-guy approach you and Lyston employ backfires especially strongly when based on such profound ignorance, which is why you're drawing sarcastic responses. And the ignorance appears to be insatiable, for at least in your case you have worked hard in your time here to maintain that ignorance, and Lyston seems destined for the same.If you'd like to understand evolution, there are plenty here who can explain it to you, and once you understand what it actually says then you can criticize it to your heart's content. But there's little point to carrying on in your current way.--PercyEdited by Percy, : Grammar.

Hi Lyston, There have been a couple of people who have touched on what you now seem to be indicating is your main question: the evolution of sexual reproduction. On the other hand, a lot of the cranky answers probably derive from your irritating and pointlessly obnoxious (not to mention arrogant) approach, with which you began right out of the starting gate in the OP. That being said, it might be interesting for other participants and potential lurkers to take a moment to review the various hypotheses that have been put forward to answer the question. In other words, this isn’t really a reply to you, since I generally don’t waste time talking to twits. If you want to participate honestly in the discussion, then I’m happy to talk with you, but drop the attitude.The origin and maintenance of sexual reproduction is an area of active research. That means that the question has not been satisfactorily answered as yet (i.e., no concensus has developed). One of the problems is that sexual reproduction - or something resembling it - apparently evolved way down at the base of the organismal tree. For instance there are several haloarchea (eg., Halorubrum) which use recombination - i.e., sexual reproduction - in the full sense of the word. There are also several single-celled eukaryotes that also use actual recombination (such as Plasmodium) during reproduction. Finally, in one sense bacterial conjugation - where genetic material is transferred between one type of bacteria and another via an exchange of plasmids - can be considered a different form of “sexual reproduction” that evolved in a completely different domain of life. In other words, not only is sexual reproduction not limited to modern multi-celled organisms, but it apparently started evolving very shortly after life itself appeared.So how did all the hanky-panky get started? There are several reasonable hypotheses (Catholic Scientist provided a wiki quote covering a number of them way back in message 5 - to which I notice you didn’t bother to reply). In general, the hypotheses can be divided into genetic and ecological explanations. CS’s wiki quote covered most of the genetic ones - if you have any questions on those, I’ll try and answer them although I’m far from an expert in genetics.I personally prefer the ecological approach. Not, I hasten to add, because the answer is intrinsically better than the more purely genetic approaches, but rather because from training and experience I have a tendency (my friends sometimes say “a purblind determination” ) to view most questions in biology in that light. The most compelling of these explanations derive from an application of what is known as the Red Queen Hypothesis (with a tip o’ the hat to Matt Ridley, who first applied the term from its broader meaning to the specific case of sexual reproduction). For those of you who are unfamiliar with the term, it derives from Louis Carroll’s wonderful book Through the Looking Glass, where Alice met the Red Queen who said, “In here, it takes all the running you can do to stay in the same place.” In essence, it is a description of the co-evolutionary arms race between a predator and its prey (or a parasite and its host). In this race, the key selection pressure on each population is its counterpart in the relationship. Simplistically, as a f’rinstance, as a predator becomes more successful in catching and killing it’s prey, the prey population may suffer a decline to a point where rare individuals with a more effective strategy or physical ability to escape come to predominate (i.e., the population is said to have adapted to the new capability of its predator), thus leading to a decline in the predator population until a more successful strategy or physical ability comes to predominate, and so the cycle begins anew. Obviously there are limitations on how far this co-evolution can continue, primarily because the predator-prey relationship isn’t the only selection pressure on the two populations. Eventually something resembling an equilibrium is likely to develop, although there will continue to be fluctuations around this equilibrium.One of the really interesting aspects of the Red Queen, and how I see it applying to the evolution of sex, is the parasite-host relationship (this isn’t the hypothesis’ only possible application to the question, but I think it is one of the easiest to illustrate, and has the advantage of having some good studies to back it up). Take a hypothetical population of clonal organisms with genotype A. If a parasite manages to infect this genotype, it will by definition be able to infect every single individual carrying the genotype. Because they’re clonal, the only thing the organisms in this case can do is to wait for the really rare beneficial mutation to appear in its lineage. Since the particular mutation may or may not appear, the population may be doomed to extinction. Let’s say the mutation DID appear, creating genotype B for instance, now we have type A in serious decline due to its parasite load in comparison to B (which for the moment is running around parasite-free). As A declines, its parasite also declines, creating selection pressure for it to adapt to the now dominant type B. If/when it does, B starts declining, A is already infected and in decline, so the clones have to come up with a genotype C, putting pressure on the parasite to adapt to C, and the Red Queen rollercoaster is well and truly underway.Now, what happens if our host population is capable of throwing up variation much faster than the parasite can? Maybe even in a single generation? Well, the parasite is now in serious trouble. This is what recombination through sexual reproduction does. It is a much faster way of creating variation than waiting around for a lucky mutation. Beginning with a simple exchange of genetic material (i.e., as in bacterial combination), as organisms and their parasites got more complex - and the inter-relations between them got more complex - the Red Queen refined the simple exchange of genetic material into something more closely resembling actual sexual reproduction. From there, it’s only a matter of continuing to refine this adaptation to where in some species we now have two genders.For those interested, here are several articles that support this issue:Dybdahl M.F, Lively C.M. 1998, “Host-parasite coevolution: evidence for rare advantage and time-lagged selection in a natural population” Evolution.;52:1057-1066;Ladle R.J. 1992 “Parasites and sex: catching the Red Queen” Trends Ecol. Evol.7:405-408;Lively C.M, Craddock C, Vrijenhoek R.C. 1990 “Red Queen hypothesis supported by parasitism in sexual and clonal fish.” Nature. 344:864-867;Moritz C, McCallum H, Donnellan S, Roberts J.D. 1991 “Parasite loads in aparthenogenetic and sexual lizards (Heteronotia binoei): support for the Red Queen hypothesis.” Proc. R. Soc. B. 244:145-149;Radtkey R.R, Becker B, Miller R.D, Riblet R, Case T.J. 1996 “Variation and evolution of class I MHC in sexual and parthenogenetic geckos” Proc. R. Soc. B. 263:1023-1032;Tobler M, Schlupp I, 2005 “Parasites in sexual and asexual mollies (Poecilia, Poeciliidae, Teleostei): a case for the Red Queen?” Biol Lett. 1(2): 166-168.

*** WARNING ***
Your kind of post is likely to atract sarcasm and mockery.Here is why:What you pointed out as being supposedly problems for the theory of evolution, are instances of what people around here simply call PRATTs (Points refuted a thosand times). That's right. the points you are making have already been refuted.To make things worse, you contradicted yourself by first caiming that god made us perfect, and then claiming that we are not perfect since we can't fly, we can't breath under water, and we don't have four arms. That would be a problem for your theory that god created us perfect. That's not a problem for the theory of evolution, though, since it does not claim that evolution made us perfect.So, you are actually defending the theory of evolution unvoluntarily. That's likely to atract mockery and sarcasm.Edited by fallacycop, : Grammar

Bad habit of mine Good! My apologies - that wasn't clear from your initial post. But I strongly reccomend you take a look at Quetzal's post, above - he did an excellent job of explaining what's currently known about the evolution of sexual reproduction. That's certainly a great start, but from your OP (and this could simply have been the result of your initial sarcasm), it really sounded like you believe individuals evolve. For instance, it sounded like you believe that evolution says that you, personally, started out a few million years ago as a single-celled organism, and that you've "morphed" your way up the "evolutionary ladder" (we don't like that term - it's more of a giant bush, and being "higher up" doesn't necessarily mean anything). That's nothing like what the Theory of Evolution states, and it's actually identical to saying that you used to be your father, and you existed as your grandfather before that. Evolution is a process that occurs over many generations of populations, not single generations or individuals. I suggest then that, next time, use less sarcasm in OPs and try to be more directly clear regarding your topic of discussion. The title, for instance, is "problems with mutations." That says nothing about sexual reproduction. Then either you were taught incorrectly (not at all uncommon at the High School level, unfortunately) or you did not understand (also not uncommon given the incredibly short amount of time typically given over to evolution in High School).The "passed down survival trait" you speak of is essencially the definition of a beneficial mutation. Mutations are small genetic changes that, in their initial appearance, were not inherited from the parent(s), but rather appear as a consequence of the DNA strand being imperfectly copied. If the host of the mutation survives to reproduce, the trait will be passed down to its offspring, simple as that. If a mutation makes survival more easy, or better yet, happens to help those who have the mutation survive better than those without it when a disaster strikes, the mutation can actually become present in the majority of the population. Further mutations, whether they are similar (as in the ever-extending giraffe neck) or not, will build upon those already passed down. Realistically, practically every feature of every organism in existence is the result of a cumulative series of mutations.When you say "wouldn't it keep having to mutate with each passing generation," you're pretty far off the mark. The original mutation is simply passed down, and in future descendants, it's not really a mutation any more - it's an inherited trait.If you mean "wouldn't additional similar mutations be required in subsequent generations to make the neck longer than the small initial change from the first mutation," then yes - to end up with a neck as long as a giraffe's, multiple similar (and quite a few supporting but not neck-related) mutations are required. But these don't need to happen in each generation - they just need to happen eventually. And they don't really need to happen at all - we know the current "end result," but there is no "final form" or goal in evolution - it's not a guided process. A trait appears, or it doesn't. If it does, it either helps the organism survive, or it doesn't. That last bit is usually influenced by the environment (natural selection). It's a random process.I remember once seeing a randomizer machine that may be relevant. It was a tall case with a glass front with many, many wooden dowels poking out of the back towards the front. Rubber balls would drop from the top, bounce randomly from each of the dowels, and eventually land in one of the pockets lined up on the bottom. Mutations are like the path of the balls - they randomply appear, for no real reason. There's no goal. The ball simply lands in one of the pockets. Subsequent balls may or may not land on a previous one. Sometimes one pocket will wind up being full of balls, while another may only have one - it's just random. Mutations are similar. A "neck extending" mutation, for example, either appears or it does not, and subsequent mutations may or may not appear and build on it. Mutations with a direct, positive efect are more likely to be passed down, so the cumulative effect can become very pronounced.Sexual reproduction isn't really any different from any other series of mutations. It's not like two individuals of a population spontaneously "decided" to be male and female. It would of necessity be a slow, cumulative process, beginning with the simpler forms of genetic exchange Quetzal mentioned. The "debate" today mostly concerns how it may have evolved, not whether it did or not - the problem being simply that sexual reproduction appeared so long ago that it likely first appeared in organisms that don't fossilize. We have to take our examples from organisms that are alive today and extrapolate, which is why we can't give you a complete "this is how it happened" story. The organisms and methods Quetzal mentioned, however, are exactly what the Theory of Evolution would predict - sexual reproduction is not unique, but is rather a modified version of a similar feature already existing in other species. And I'm sorry, but it's completely and totally wrong. That's like saying amputees should have children born without limbs, or that my child may have a birthmark if I get a tattoo.Mutations and evolution work by genetic changes, which are already set before you're born. Disfiguring your body in any way will have no bearing whatsoever on your offspring. If this is really the way your teacher explained it, he should be fired, and it's no wonder you have some severe misconceptions surrounding evolution. And again, that's compeltely and totally wrong. If I work out and become a body builder, my children will not be born with bulging muscles. If I break my arm repeatedly and force it to heal in a strange shape, my children will not be born with such a deformity. If I suffer burns on my body, my children will not inherit the scars.Mutations and evolution are genetic in nature, and have nothing to do with changes within your lifetime. Quite the contrary. You're taking the position that sexual reproduction needs to form spontaneously and suddenly, with both a male and a female gender evolving at the same time. That certainly is quite a jump, and it would be somewhat similar to a giraffe suddenly "evolving" a new head. You're right to ridicule that idea...the problem is that this has nothing to do with what the Theory of Evolution predicts.Evolution predicts that no feature should be unique, no feature should spring up fully formed like what you're describing. Instead, all features of all organisms should be slightly modified versions of the same feature in a pre-existing species. Giraffe necks did not spontaneously "mutate" in a day - they are slightly modified versions of the same feature in their ancestors. So too is sexual reproduction as humans experience it not unique, and it did not appear "fully formed" with a male and female present. It began, as Quetzal ponted out, as simple genetic exchange. In many species, all individuals are simultaneously both genders - hermaphrodites. The change to exclusively single-gender individuals would have been a mutation based on that.Imagine a mutation in a hermaphroditic species where one individual is born with a mutation that makes the female fetures either absent or nonfunctional. This individual could be said to be the first "male." He'd still be able to reproduce with the rest of the population using his male features and their female features - he just wouldn't be able to have it "both ways" any more. It's a small change for an individual, but many cumulative mutations along those lines can eventually lead to a full seperation of the sexes if selective pressure is applied. There isn't really a "why" in evolution. We can tell you why a feature is beneficial, but why a feature forms in the first place is really tied to random mutations. The only thing that keeps the whole mess from being total random chaos is natural selection, which ensures that primarily neutral and beneficial features are passed down, and lethally harmful mutations are removed from the gene pool. Evolution doesn't work that way. Mutations are small changes, and they are mostly random. There's no goal, and you can't really say "why don't I have four arms, that would be useful" as evolution doesn't simply add on whatever is useful - it's not an intelligent process, any more than the formation of ice crystals are intelligent. Evolution is the cumulative effect of random mutations working within the limits of chemistry, guided by natural selection.We use computer programs modeled after evolutionary processes to solve problems, by the way. They produce some very interesting solutions, very much like evolution in the real world. Continue to approach us this way rather than the sarcastic, insulting tone you used in your OP, and you'll get more reasoned posts. If you simply want to learn more about what the Theory of Evolution actually styates, you've definitely come to the right place.

... and consisting of actual statements rather than the stupid gibble-gabble that you've made up in your head. True, we should also mention the existence of random variation. What a strange non sequitur. If you know what it means, do tell us. There has been a serious attempt to reasearch this subject, which is still ongoing, and all the creationist lies in the world won't make that go away.Meanwhile, creationists don't have to do any research, do they. 'Cos all you guys have to do is sit on your arses reciting: "I don't know how it happened. Therefore I do know how it happened. God did it by magic".Or can you point me to one piece of creationist research on this subject?'Scuse me, did you use the phrase "intellectual bankruptcy"? Wow. A creationist finally manages to understand a point about evolution that we've only been trying to explain for the last century or so, and immediately he thinks that it's a problem for evolution rather than one of the crucial aspects of the theory. One of the more interesting aspects of creationism is the deeply stupid lies they tell about there opponents.Obviously, in the real world, the one outside CTD's head, anyone who was "dead certain" that CTD's bibble-babble "killed" evolution would be a creationist. If he has ever thought about this for five seconds, he knows that as well as you or I.His use of the word "fantasy" is as amusing, in this context, as his use of the words "intellectual bankruptcy", above.

quote:

---

In other words, you accused evolution of not being aware of something that is actually one of its defining characteristics.

---

Nonsense. I was merely pointing out that in a situation where it will serve to give the illusion that a creationist doesn't know what he's talking about, there are individuals who will happily "forget" even the most fundamental and obvious scientific facts.If I thought evolutionists didn't know this, I would expect it to go over their heads. It didn't because they do know it (when they choose to remember).

quote:

---

Those like you and Lyston who have no idea what evolution actually says can convince others equally ignorant that evolution has some flaw and then cast ridicule at the strawman you've built.

---

Strawman? Anyone can see for themselves. Pretending hermaphrodites are easier to evolve doesn't answer the question of how they'd evolve. Explaining WHY evolution would desire to evolve a thing says nothing about HOW it would do so. And meaningless obfuscation is meaningless obfuscation.Now if anyone can provide a straightforward, direct answer to HOW sexual reproduction could evolve I'd be curious to see it.Oh, almost left one out: listing different reproductive designs doesn't explain how they could evolve either. It actually means there are that many more creatures evolutionism needs to give account for. Darwin himself said it's required to account for everything, but anyone demanding that it actually do so is routinely accused of "arguing from incredulity".

quote:

---

Lyston's problems with mutations are mistaken because his understanding of evolution is fatally flawed beyond belief, as apparently is your own.

---

Your mistake lack of faith for lack of understanding.Lyston is correct: sexual reproduction has to begin as a mutation or group of mutations in an individual. There's no other way to get the ball rolling. This mutation has to be passed on.I said:

quote:

---

I've always thought the funnier part that even if male and female arise in the same place, species, and time; there's an overwhelmingly good chance they wouldn't understand their new roles. You know, with nothing hardwired into the circuits yet they'd still be out of luck.

---

Perhaps this is what you mean by "strawman"? Well, even if hermaphrodites arose first, they'd need to be hardwired to reproduce after their fashion.How is "evolution did it" in any way superior to "God did it"? At least God knows what He's doing. Evolution only knows what it's doing when it suits an evolutionist argument, like the one above. Any time evolutionists answer a HOW question with a WHY answer, they attribute motive to their god.

Yet no one interpreted it this way. Either you meant what you appeared to be saying and wildly misunderstand evolution, or you were so wildly off-topic that no one could see what point you were making.This thread is about the evolution of sexual reproduction (I'll modify the title). If you have off-topic points to make in obscure ways, such as about how forgetful evolutionists are about their own theory, then please propose a new thread.--Percy

There's both a how question and a why one in the O.P.The "why" one is "why doesn't natural selection crush it", "it" meaning sexual reproduction. Because more is known about that than the "how" one (how did sexual reproduction come about in the first place) is probably why the answers in this thread deal more with it. There's no question of motive related to either question, as you should know.There are various feasible hypotheses on the "how" question, but no strong theory, so, like abiogenesis, it's still a good area to stick your God of the Gaps in.Because evolution is something that is known to happen. Something for which there is evidence.Creation mythologies are something humans are known to invent, as evidenced by the enormous number of mutually exclusive ones from many different cultures.Here's a site you'll enjoy as you like magic. Creation Myths including the Jewish one

quote:

---

Much wordier, indeed. Millions of words have been written about the benefits and costs of sexual reproduction. But in the mind of a superstitious fool, this becomes "no serious attempt to tackle it".

---

The "it" in my sentence refers to the HOW question. Millions of words about WHY don't count. Evolution's motives are distinct, separate question.Darwin wrote

quote:

---

If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.

---

There has never been a plausible scenario imagined which accounts for the reproductive systems to form by numerous, successive, slight modifications. Pardon me for agreeing on this point with your prophet.Edited by CTD, : Removed inappropriate residual title

Perhaps you should try learning the first thing about evolution. That way you wouldn't babble about "evolution's motives" and you might be able to begin to grasp what is, after all, quite a simple concept. If, by "your prophet", you mean Charles Darwin, then evidently you are not agreeing with him, because the two sentences: ... are clearly logically independent.

Demonstrate...not possible.That's what I call an Everest-sized "if"

quote:

---

There's both a how question and a why one in the O.P.

---

It's not hard to designate which question one is answering. For example, "Once it was present, natural selection would favor sexual reproduction because..."This is distinctly different from "Here's how it happened: it happened because..."I see a little "We might be able to start a story with...", but nothing clear and explanatory, and nothing approaching the full story from no sexual reproduction to the male & female sexes. That's what the O.P. asked for. That's what's required lest Darwin's "theory" break down.Now the others claim it'd take several small steps, but from the first sentence of message #9 I get the impression you're of the sect that believe evolution can overcome absolutely any odds, no matter how great. If so, you shouldn't have a problem with the "overnight" scenario originally presented.

For example, when you babble about evolution having "motives", you have forgotten "even the most fundamental and obvious scientific facts", and this does indeed create the impression that a creationist doesn't know what he's talking about.I am not sure why you describe this effect as an "illusion". What perfect gibberish. You have forgotten "even the most fundamental and obvious scientific facts". You do not know what you are talking about.

I agree with your point that this is not a good way to test the theory, because it requires the challenger to prove that "you can't get there from here" by any conceivable pathway. No, scratch "conceivable".For this reason, when I'm asked to give evidence for evolution, I mention the things which are strongly testable ... the contents of the fossil record, molecular phylogeny, comparative morphology, and so forth, rather than putting the inability of creationists to prove that sex can't have evolved anywhere in my list.As you observe, it would be a huge mountain to climb --- if creationists tried to climb it. Instead, they rely on those two old standbys: "I don't understand it, so goddidit" and "you can't tell me how it happened in every detail, so goddidit". They can't climb mountains, but they can get to the top of molehills.Given this, you might think that they would be better advised to attack evolution on points where it is highly testable. And they would indeed be better advised to do so, if they were right.