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> This is a misreading of evolution. To start with, we are not optimal. Not even locally optimal. No species is. Who is the optimal human? Is that person alive

by hpvic03 14y ago

> This is a misreading of evolution. To start with, we are not optimal. Not even locally optimal. No species is. Who is the optimal human? Is that person alive today? Optimal refers to having the highest probability of surviving and reproducing in the given environment. Since humans dominate the earth, we are more optimal than any other species of animal. From a genetics standpoint, the most "optimal" human would bear as many children as possible while still maintaining the earth as a hospitable environment, and minimize all potential risk factors that could harm his or her children. So yes, there is a theoretical maximum for evolution that we haven't reached, but we will likely never reach it. > Second, you haven't considered timescale. You say "get weeded out". How long does that process take?...How can you tell that the behavior you are examining increases fitness or decreases fitness but happens to be in the same genome as something else which greatly increases fitness...Some researchers then point to the increase in nose picking in the general population and conjecture that nose picking must have conferred some genetic advantage. But this is wrong. Nose picking came along for the ride. Meiosis randomly splits chromosomes via crossing over, then pulls out one half of the chromosomes (23) to later pair with the 23 chromosomes from the other zygote (sperm or egg cell). After enough iterations this process can isolate genes that increase or decrease fitness. > Third, the coupling between behavior and genes can be extremely tenuous. 300 years ago you could look at European populations and conclude that they were genetically predisposed towards monarchy. Some believed that this was the natural order of things. Where's the gene for democracy? 1000 years ago you could conclude that there was a genetic predisposition towards Catholicism. What genetics caused people to chose that over, say, Zoroastrianism? Culture certainly affects behavior, yet humans have sex and produce kids in every culture. When it comes to survival and reproduction, genetics preempts culture when it comes to individual behavior. Democracy isn't an individual behavior, it's a cultural idea. People typically live under whatever government they're born into. Same with religion. It seems logical that women could be genetically predisposed to desire multiple partners in order to increase the variety of genes and thus enhance the fitness value of their offspring. However, I do not know how you could prove or disprove this idea.

dalke 14y ago
> Since humans dominate the earth, we are more optimal than any other species of animal. LOL! You are amazingly self-centered. Yes, humans are the most numerous mammal, with rats second. There's 50 billion chickens. By your definition, chickens are more optimal than humans. The nematode populations are measured in up to millions per square meter. With an estimated 1 million species of nematodes, the average nematode species population is comfortably higher than that of humans. There's an estimated one to ten quadrillion ants in the world across 22,000 species, so about 500 billion ants per species, on average. Again, higher than the number of humans. There are about 1 million wheat plants per acre and 60 million acres planted gives a wheat plant population of over 1 trillion. (It hard to find numbers for non-commercial plant populations.) But wait! Why look at multicelled animals? Bacteroides fragilis, Bacteroides melaninogenicus, Bacteroides oralis, Enterococcus faecalis, and Escherichia coli are found in basically every person's gut, so there's definitely way more of each of those species than humans. To say nothing of those species populations elsewhere. It's really hard to find estimates of the total number of a single bacteria species. Would you care to revisit your statement that humans "are more optimal than any other species of animal"? At the very least you should acknowledge that chickens are more optimal than humans. > the most "optimal" human would bear as many children as possible while ... You wrote "his or her children" but you meant to write "descendants." In any case, you are viewing things on the wrong level. Evolution works on genes, not individuals. Humans, like other primates, are social beings. It is part of our evolutionary strategy to help others of our species, especially those we recognize as family. You'll easily notice that other mammals don't all follow the strategy you say is the evolutionary mandate. The naked mole rat is a favorite example; only the queen and one to three males reproduce, while the rest are sterile workers. Why do those workers work if they don't have children? Some animals eat their own young, or preferentially feed the strongest (hence how cuckoos get others to raise their young) and leave the weak to die if there isn't enough food. These are obvious counter-examples to your assertion that parents "minimize all potential risk factors that could harm his or her children." In addition, why did you choose a definition of "optimal" based on population count instead of, say, species longevity? Surely the Queensland lungfish, where fossils identical looking to the modern form exist from 100 million years ago, has a stronger claim to being optimal than H. sapiens' scant 500,000 years. > After enough iterations this process can isolate genes that increase or decrease fitness. Obviously. My point was regarding the length of time it takes. If "enough iterations" for humans is 50,000 then 1.5 millions years is longer than H. sapiens has been around. Now factor in that most mutations are either neutral or negative, and you end up with a lot of slightly detrimental mutations which last for a very long time. How then do you tell that an observed behavior, with no obvious, direct benefit (like nose picking) is evolutionarily beneficial or detrimental but following along on the coat tails of a more beneficial mutation?

by hpvic03 14y ago

dalke 14y ago

> Since humans dominate the earth, we are more optimal than any other species of animal. LOL! You are amazingly self-centered. Yes, humans are the most numerous mammal, with rats second. There's 50 billion chickens. By your definition, chickens are more optimal than humans. The nematode populations are measured in up to millions per square meter. With an estimated 1 million species of nematodes, the average nematode species population is comfortably higher than that of humans. There's an estimated one to ten quadrillion ants in the world across 22,000 species, so about 500 billion ants per species, on average. Again, higher than the number of humans. There are about 1 million wheat plants per acre and 60 million acres planted gives a wheat plant population of over 1 trillion. (It hard to find numbers for non-commercial plant populations.) But wait! Why look at multicelled animals? Bacteroides fragilis, Bacteroides melaninogenicus, Bacteroides oralis, Enterococcus faecalis, and Escherichia coli are found in basically every person's gut, so there's definitely way more of each of those species than humans. To say nothing of those species populations elsewhere. It's really hard to find estimates of the total number of a single bacteria species. Would you care to revisit your statement that humans "are more optimal than any other species of animal"? At the very least you should acknowledge that chickens are more optimal than humans. > the most "optimal" human would bear as many children as possible while ... You wrote "his or her children" but you meant to write "descendants." In any case, you are viewing things on the wrong level. Evolution works on genes, not individuals. Humans, like other primates, are social beings. It is part of our evolutionary strategy to help others of our species, especially those we recognize as family. You'll easily notice that other mammals don't all follow the strategy you say is the evolutionary mandate. The naked mole rat is a favorite example; only the queen and one to three males reproduce, while the rest are sterile workers. Why do those workers work if they don't have children? Some animals eat their own young, or preferentially feed the strongest (hence how cuckoos get others to raise their young) and leave the weak to die if there isn't enough food. These are obvious counter-examples to your assertion that parents "minimize all potential risk factors that could harm his or her children." In addition, why did you choose a definition of "optimal" based on population count instead of, say, species longevity? Surely the Queensland lungfish, where fossils identical looking to the modern form exist from 100 million years ago, has a stronger claim to being optimal than H. sapiens' scant 500,000 years. > After enough iterations this process can isolate genes that increase or decrease fitness. Obviously. My point was regarding the length of time it takes. If "enough iterations" for humans is 50,000 then 1.5 millions years is longer than H. sapiens has been around. Now factor in that most mutations are either neutral or negative, and you end up with a lot of slightly detrimental mutations which last for a very long time. How then do you tell that an observed behavior, with no obvious, direct benefit (like nose picking) is evolutionarily beneficial or detrimental but following along on the coat tails of a more beneficial mutation?