"<a href=""https://www.youtube.com/watch?v=hppbxV9C63g&amp;t=1h53m07s"">1:53:07</a> natural selection takes a long time. sexual selection", is different, no?,(reply>), @JimBob1937 "You can't suddenly introduce many new genetic variations"? Then why do childhood diseases like cancer and blindness exist? If their survival rates are resolved, then their genetics are going to flood the gene pool. This is obvious.<br><br>You're torturing the definition of directionality. Admitting most is diametrically opposite to admitting only a minority. Conflating these is absurd.<br><br>Viability means nothing without fertility. In fact it has been the case for millions of years that about half of males never reproduce. If anything, this proportion has only grown.<br><br>"where are these gene variants suddenly coming from"?<br><br>FROM THE MASSIVE PROPORTION OF MALES WHICH FAIL TO REPRODUCE. WHICH HAS ALWAYS EXISTED.<br><br>"There is no known mechanism that would cause previously unfit variations to suddenly be reintroduced as soon as pressures change."<br><br>You falsely assume that unfit variations died out millions of years ago. This is manifestly absurd.<br><br>"Most research shows political views to be more due to environmental exposure"<br><br>You are entirely discounting the massive effect that parental genetics has on environment. ENVIRONMENT IS EXTREMELY HERITABLE. Hardly any sons of European nobles randomly woke up in the Sahara.,(reply>), @blue internet , sexual selection can be considered a mechanism of natural selection. You're trying to make a statement that natural selection is different than sexual selection on a grand scale, which I don't think fits. The most obvious sexual selection example is that you cannot select someone who is dead, but obviously this isn't your intent by the usage of the term. However, sexual selection has always accounted for gene expressions deemed valuable by society and hence the women and men themselves, this is part of natural selection in a sense (read on). Attractiveness and other such qualities are selection pressures just as well. This is why I stated, "Sexual selection is the mechanism for this," in the first reply. They can be deemed separate from natural selection, hence why we have two terms, but most reference to natural selection and sexual selection as 'natural selection' as a whole, or just, 'selection.' This is because sexual selection blurs into natural selection, as well as provides general context. What is deemed sexually valuable may be due to natural selection factors. A heavyset man may be attractive in an environment of food scarcity, as an example. This can illustrate that this individual has traits that maybe allow him to store food more readily, or he is more fit for the environmental pressures and hence able to acquire more food. These can be genetic selective traits. You see this over the course of human history were beauty standards shifted in response to various types of environmental pressures. There are indeed cases where sexual selection can occur in scenarios where traits are negative or neutral to natural selection. However, for negative, natural selection tends to correct for it, and for neutral, this just results in the spread of neutral traits, which I never argued against. Evolutionary direction for neutral traits tends to be less strong. However, even Darwin who originally suggested sexual selection as a mechanism understood that selections can overlap between natural and sexual, and hence the line can be blurred. With that said, I will admit some fault in trying to equate the two, too much. In any case, Haier in this context seems to be using the term natural selection to refer to all evolutionary pressures, the term natural selection carries with it the context of evolutionary genetic selection pressures, which would be natural and sexual. Context is important to understand the term usage, even if it isn't technically correct., it can be convenient.<br><br>"natural selection takes a long time. sexual selection, is different, no?"<br><br>Is your original point. To which the response is still, no. They can overlap, but even in events where the two don't agree, the directionality of evolution due to them is no different in the scale of time. Why would different selection mechanisms create different time scales? Severity of pressure is the only thing that can do this, and if it is to act rapidly, it largely can only do so by subtraction. You can't suddenly introduce many new genetic variations, you can only suddenly remove them. So, even if one is stronger than the other, genetic traits need time to be introduced into a population to be tested by whatever selection mechanism is at play. Overall evolution, in the time scale, is dictated by the introduction of new variations, which is limited no matter the selection mechanism.  In the context of sexual selection, evolution will not occur any a faster rate compared to natural selection. Existing genes still take a specific amount of time to propagate through the population, and new genes take a specific amount of time to stochastically occur and then propagate. The limiter is the genetic variation creation and propagation, not the selection mechanisms. <br><br>" The idea that the "direction" of evolution is invariant is patently ridiculous."<br><br>I never said it is invariant... I said the opposite, the direction is based purely on selection pressures. These pressures can be environmental, or sexual partner preferences. However, I did state that a sudden lack of selection pressures, will tend to reduce the directionality of evolution. The freedom of genetic expression to explore the solution space is given by variability within the genetics. This can come from mixing new genetic variations into a population, or from things like mutations. However, when selection pressure is reduced, these variations are only limited by viability (not causing immediate harm) rather than being directed by other pressures. This indeed reduces the directionality of the evolution from these mutations. Mutations without pressures are stochastic by nature. With that said, there is unlikely to ever be a purely unselective pressure environment, but there are certainly gradations of selection severity. <br><br>" You assume that the genes that were unfit a few hundred years ago are still unfit,"<br><br>I never said any such thing and don't believe that. Gene variants that were unsuccessful in the past may still be so, or not, if selection pressures have shifted. It also gets more complex in that phenotypes deemed valuable now may be a combination of some gene expressions that are bad in other contexts. Genetics isn't always clear cut on being fully positive or fully negative.<br><br>"a rapid reduction in selection pressure would radically increase the proportion of genes that a few generations ago were unfit."<br><br>No it won't... where are these gene variants suddenly coming from? For a genetic variation that was unfit previously, and hence in low existence in a population, to come, it has to be reintroduced into a population. This means through propagation by the minority that have this variant as well as mutations that reintroduce this variant... any such mechanism to retest such variations will come about very slowly. There is no known mechanism that would cause previously unfit variations to suddenly be reintroduced as soon as pressures change. This by the very mechanism of natural selection is prevented since previously unfit variations were trimmed from the population in the first place. A change or reduction in pressures merely gives more freedom for variations to occur, but this freedom has to build up over time since previous selection pressures created variation homogeneity around such pressures (at least for things positive/negative relating to those pressures, neutral changes tend to be more stochastic again).<br><br>"My theory was that sexual selection is as strong as ever, but it accounts for mainly psychological characteristics such as politics, obediance, and intelligence rather than strength, speed, or resistance to disease. "<br><br>I still say the variations have to be there for this type of selective pressure to have a large impact on the evolutionary timescale, which seemed to be your original statement. Further, I would say some of those traits, like intelligence, cross over into both natural and sexual selection. I'd be interested, but I would be surprised if politics has a large genetic component, and hence isn't likely to be an evolutionary director if it were selected for. Most research shows political views to be more due to environmental exposure. As for obedience, you would need to be more specific, but I would also be surprised if that were actively selected for in sexual selection (maybe cultural). In first world countries, you are likely correct, as natural selection is more limited these days and sexual selection is likely more prominent... but I would highly caution how far you take this idea. This will not speed up evolution, it will not direct evolution for sexual preferences that are not likely to be strongly genetically linked (like politics), nor will it suddenly create a high genetic variation in a short period of time. <br><br>At this point you seem to be making up statements and arguing against those (strawman arguments), or perhaps I've been unclear. So, on that note, I bid you a good evening, but will be unlikely to continue this conversation going forward.,(reply>), @JimBob1937 A sudden reduction in sexual selection pressure might inhibit evolution in a particular direction, but you're ignoring that genetic diversity is, in itself, a direction. But that was never my theory. I'm just debunking your comment. My theory was that sexual selection is as strong as ever, but it accounts for mainly psychological characteristics such as politics, obediance, and intelligence rather than strength, speed, or resistance to disease. The idea that the "direction" of evolution is invariant is patently ridiculous. You assume that the genes that were unfit a few hundred years ago are still unfit, just somewhat less so. That is a completely unfounded assumption. Daily life today is nearly unrecognizable to pre-industrial people. To assume that it's all window dressing is as laughable as it is false.,(reply>), @blue internet , I think you have the wrong idea of evolution. It's really just a, 'good enough' system. A lot of less fit genes will still propagate in times before the industrial revolution as well. This is because you just need to survive long enough to pass those genes on. Social status has always been a selection criteria, so that didn't really change either. Hence, I go back to my original point, true natural selection is quite slow with evolution being an accumulation of many smaller mutations over a long period of time. A decrease in selection pressures just slows down a push in a specific evolutionary direction. Evolution is an optimization algorithm optimizing for certain selection pressures, lessening these pressures merely makes the algorithm less directional.<br><br>"natural selection takes a long time. sexual selection, is different, no?"<br><br>Is your original point, and my original response still is entirely valid:<br><br>"Natural selection's influence takes longer to show as phenotypical differences in a population. Sexual selection is the mechanism for this, as that is the primary mechanism for genotypes to be carried over to a new generation, but the influence is gradual. It is only not gradual if there is a very strong selection event, like a lethal sickness that a specific genotype is resistant to."<br><br>Then you stated:<br>" I would say that rapid industrialization and globalization was a strong selection event"<br><br>To which I would still say, no. A lessening of selection pressure is not a strong selection event. It is an even weaker selection than what came before it, slowing down what evolution that may take place due to being less directional.,(reply>), @JimBob1937 leveling the playing field changes the proportions, and proportion is a zero-sum game. at this scale, proportions are what determine the average, which is the topic being discussed