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Thread: Scientists Cite Fastest Case of Human Evolution

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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Redress View Post
    And you are basing this statement on what?
    I think he is referring to the scarcity of beneficial mutations, and the improbability that that particular combination would actually come up to BE selected and conserved in a mere 3,000 years among a relatively small population.

    We see mutations all the time. In the vast majority of cases, they kill the mutated fetus, or are a survival-negative or survival-neutral, like calves born with an extra set of useless legs.

    For something so singularly appropriate and useful to turn up (by random chance) to be conserved/selected in 3,000 years in a smallish population seems very unlikely. Digsbe's hypothesis that those who already had the genes survived to reproduce and those who didn't didn't, seems much more probable.

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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Goshin View Post
    I think he is referring to the scarcity of beneficial mutations, and the improbability that that particular combination would actually come up to BE selected and conserved in a mere 3,000 years among a relatively small population.

    We see mutations all the time. In the vast majority of cases, they kill the mutated fetus, or are a survival-negative or survival-neutral, like calves born with an extra set of useless legs.

    For something so singularly appropriate and useful to turn up (by random chance) to be conserved/selected in 3,000 years in a smallish population seems very unlikely. Digsbe's hypothesis that those who already had the genes survived to reproduce and those who didn't didn't, seems much more probable.
    If you read the article, there is this:

    The Beijing team analyzed the 3 percent of the human genome in which known genes lie in 50 Tibetans from two villages at an altitude of 14,000 feet and in 40 Han Chinese from Beijing, which is 160 feet above sea level. Many genes exist in a population in alternative versions. The biologists found about 30 genes in which a version rare among the Han had become common among the Tibetans. The most striking instance was a version of a gene possessed by 9 percent of Han but 87 percent of Tibetans.
    The genes where already in the population as a survival neutral gene, and for those living at the high altitude, it was heavily selected for(3 times the infant mortality for those without compared to those with at that altitude).
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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Redress View Post
    If you read the article, there is this:



    The genes where already in the population as a survival neutral gene, and for those living at the high altitude, it was heavily selected for(3 times the infant mortality for those without compared to those with at that altitude).
    So if the gene was already present in the "control population" (han), then it seems likely that digsbe's point, that it wasn't a mutation in the Tibetan population but rather the survival of those who HAD the gene sequence that resulted in the current situation. An adaptation through conservation of an existing gene-set in survivors, rather than a "new" set of genes produced by mutation.

    It might seem like a fine point, but when arguing the difference between "microevolution" (expression of existing genes for environmental adaptation) and "macroevolution" (series of selected mutations producting NEW genes, eventually changes a tree-lizard into a bird) it is a significant point.

    Examples of microevolution taking place around us abound: how birds of the same species have different shaped beaks on this island than on that island, due to the type of food supply, is a way that existing genes are expressed differently based on the environment. "Macroevolution", where NEW genes come into existence via mutation and result in an offspring that has a radical and obvious genetic difference from the parent species... to my knowlege we have yet to observe an recordable event that can be thus labeled with indisputeable evidence, outside of assumptions based on the fossil record.
    Last edited by Goshin; 07-03-10 at 01:14 PM.

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    Re: Scientists Cite Fastest Case of Human Evolution

    It is as Goshin says, evolution requires random chance in order to go to the next step of natural selection. The fact that these genes already existed though proves that nothing has been "evolved" or altered genetically. It's as simply as this. Those who already had the genes that better suited them to live at high altitude were the ones that survived and passed on that gene to their kids. Those without those genes either died or moved back to lower altitudes. This is a case of natural selection, not evolution. Regardless, the 3,000 years would be insufficient time according to evolutionary scales for these 30 genes to change into something beneficial through random mutations.
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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Goshin View Post
    So if the gene was already present in the "control population" (han), then it seems likely that digsbe's point, that it wasn't a mutation in the Tibetan population but rather the survival of those who HAD the gene sequence that resulted in the current situation. An adaptation through conservation of an existing gene-set in survivors, rather than a "new" set of genes produced by mutation.

    It might seem like a fine point, but when arguing the difference between "microevolution" (expression of existing genes for environmental adaptation) and "macroevolution" (series of selected mutations producting NEW genes, eventually changes a tree-lizard into a bird) it is a significant point.
    You missed the "survival neutral gene" part. Just as not all mutations are helpful, neither are they always harmful. Some genes get passed down often because it's not particularly necessary that they don't.

    However, once those neutral traits are actually proved necessary to survival, only those who possess them live long enough to reproduce and those traits are expressed with near perfect consistency. That's how natural selection works.

    While technically a tree-lizard can evolve into something that flies, your statement gives me the feeling that you don't understand that many, many millions of years go into speciation. I could be wrong (about you not getting this point), it's just that it sounded a little too similar to the oft-given "have you ever seen a cat turn into a dog?" creationist rebuttal.

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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by digsbe View Post
    It is as Goshin says, evolution requires random chance in order to go to the next step of natural selection. The fact that these genes already existed though proves that nothing has been "evolved" or altered genetically. It's as simply as this. Those who already had the genes that better suited them to live at high altitude were the ones that survived and passed on that gene to their kids. Those without those genes either died or moved back to lower altitudes. This is a case of natural selection, not evolution. Regardless, the 3,000 years would be insufficient time according to evolutionary scales for these 30 genes to change into something beneficial through random mutations.
    The genes themselves were not "altered" in this example, but rather gene groups .

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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Cardinal View Post
    You missed the "survival neutral gene" part. Just as not all mutations are helpful, neither are they always harmful. Some genes get passed down often because it's not particularly necessary that they don't.

    However, once those neutral traits are actually proved necessary to survival, only those who possess them live long enough to reproduce and those traits are expressed with near perfect consistency. That's how natural selection works.

    While technically a tree-lizard can evolve into something that flies, your statement gives me the feeling that you don't understand that many, many millions of years go into speciation. I could be wrong (about you not getting this point), it's just that it sounded a little too similar to the oft-given "have you ever seen a cat turn into a dog?" creationist rebuttal.

    I'm aware that the process is assumed to be a long-term and gradual thing, according to some versions of evolution (but there are other schools of thought on this as well, regarding the sudden explosion of speciation during certain periods of time).

    I've always felt that one of the weakest links in evolutionary theory is how some of the most extrordinarily useful, specialized and complex things, like eyes, spinal cords, feathers, and a giraffe's neck, are the result of random mutations being selected by environmental pressures. The number of variables that would have to go into the pool to allow for such incredibly complex and dramatically important results would be inconceivably huge. Even given that we're talking about millions of organisms and millions of years, the idea that a sufficient number of beneficial mutations could occur to result in organisms of such vastly greater complexity than their forebears strains the imagination.

    One of the laws of thermodynamics states that systems tend to devolve from more-organized-states to less-organized-states in the absence of outside influence, in other words entrophy. I find it difficult to believe that a paramecium could eventually evolve into an owl, no matter how long the time-scale, without intelligent direction being involved in the process.
    Last edited by Goshin; 07-03-10 at 01:45 PM.

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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Goshin View Post
    So if the gene was already present in the "control population" (han), then it seems likely that digsbe's point, that it wasn't a mutation in the Tibetan population but rather the survival of those who HAD the gene sequence that resulted in the current situation. An adaptation through conservation of an existing gene-set in survivors, rather than a "new" set of genes produced by mutation.

    It might seem like a fine point, but when arguing the difference between "microevolution" (expression of existing genes for environmental adaptation) and "macroevolution" (series of selected mutations producting NEW genes, eventually changes a tree-lizard into a bird) it is a significant point.

    Examples of microevolution taking place around us abound: how birds of the same species have different shaped beaks on this island than on that island, due to the type of food supply, is a way that existing genes are expressed differently based on the environment. "Macroevolution", where NEW genes come into existence via mutation and result in an offspring that has a radical and obvious genetic difference from the parent species... to my knowlege we have yet to observe an recordable event that can be thus labeled with indisputeable evidence, outside of assumptions based on the fossil record.
    Your understanding of what micro and macro evolution are is not exact, but that is understandable since definitions vary. To give us working definitions, using my favorites:

    Macroevolution-"large-scale patterns or processes in the history of life, including the origins of novel organismal designs, evolutionary trends, adaptive radiations and extinctions"

    microevolution-"evolution that occurs at or below the level of species, such as a change in the gene frequency of a population of organisms or the process by which new species are created"

    This is microevolution clearly, but that does not make it not evolution in action. It is the process of evolution, as it occurs. Survival in an environment is selecting for genes. That is evolution.
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    Quote Originally Posted by Fiddytree View Post
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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Redress View Post
    Your understanding of what micro and macro evolution are is not exact, but that is understandable since definitions vary. To give us working definitions, using my favorites:

    Macroevolution-"large-scale patterns or processes in the history of life, including the origins of novel organismal designs, evolutionary trends, adaptive radiations and extinctions"

    microevolution-"evolution that occurs at or below the level of species, such as a change in the gene frequency of a population of organisms or the process by which new species are created"

    This is microevolution clearly, but that does not make it not evolution in action. It is the process of evolution, as it occurs. Survival in an environment is selecting for genes. That is evolution.

    As you say, the definitions vary.

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    Re: Scientists Cite Fastest Case of Human Evolution

    Quote Originally Posted by Goshin View Post
    I'm aware that the process is assumed to be a long-term and gradual thing, according to some versions of evolution (but there are other schools of thought on this as well, regarding the sudden explosion of speciation during certain periods of time).

    I've always felt that one of the weakest links in evolutionary theory is how some of the most extrordinarily useful, specialized and complex things, like eyes, spinal cords, feathers, and a giraffe's neck, are the result of random mutations being selected by environmental pressures. The number of variables that would have to go into the pool to allow for such incredibly complex and dramatically important results would be inconceivably huge. Even given that we're talking about millions of organisms and millions of years, the idea that a sufficient number of beneficial mutations could occur to result in organisms of such vastly greater complexity than their forebears strains the imagination.

    One of the laws of thermodynamics states that systems tend to devolve from more-organized-states to less-organized-states in the absence of outside influence, in other words entrophy. I find it difficult to believe that a paramecium could eventually evolve into an owl, no matter how long the time-scale, without intelligent direction being involved in the process.
    If you have not, read The Blind Watchmaker by Dawkins. He specifically tackles this issue in detail(and thankfully this is before his fixation on the evils of religion), and shows how something as complex as the human eye can be easily explained by evolution.
    We became a great nation not because we are a nation of cynics. We became a great nation because we are a nation of believers - Lindsey Graham

    Quote Originally Posted by Fiddytree View Post
    Uh oh Megyn...your vagina witchcraft is about ready to be exposed.

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