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The genes themselves were not "altered" in this example, but rather gene groups .
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.
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.
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. :shrug:
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.
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.
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.
During the past 100,000 to 200,000 years, anatomically modern humans successfully colonized a diverse range of environments across the planet. Some of the most extreme of these environments are found on the high-altitude plateaus of Central Asia and the Andes. The Tibetan Plateau appears to have been inhabited for 25,000 years, and permanent settlements have been established at elevations of 3500 to 4500 m (1, 2). Residents of these lofty altitudes descend from a long line of highland ancestors who lived long enough to reproduce in spite of the physiological challenges associated with chronic oxygen deprivation. Thus, studies of indigenous high-altitude residents provide the opportunity to identify genes that may have played a role in hypoxia adaptation. On pages 72 and 75 of this issue, Simonson et al. (3) and Yi et al. (4), respectively, combine genomic and candidate-gene analyses to identify the genetic basis of high-altitude adaptation in Tibetans. Together with another recent analysis (5), the studies reveal that genes in the hypoxia-inducible factor (HIF) oxygen signaling pathway have been subject to strong and recent positive selection in Tibetan highlanders.
people in Denver Colorado live at altitudes of 5,000 feet, thats 16% less oxygen than sea level...whats their deal? the article went on to say that genes in the Tibetans "adapted"
if humans evolved from monkeys, why do we still have monkeys?
Ughhh, why don't you do some research. Nobody ever said we evolved from Monkeys. We all evolved from a common anscetor and branched off. So techinaclly we are cousins, Apes being are closest cousin. Notice how bone for bone muscle for muscle Apes and Humans are very similar.
watch this...Richard Dawkins shows what I am talking about.
The way I see your argument is this:
The universe and all it's life forms are much too complex to have existed on their own or to have always existed.
Therefor, I will stipulate an even more complex entity that existed on it's own or has always existed.
I guess my argument is that if you think that the universe is too complex to have just always existed or to have been created through natural phenomenon that we just don't understand, then you must make the same argument about any proposed God, since a creator would by definition have to be more complex than it's creation.
Using Ockams razer, we simply reduce "The universe was created by God, who has always existed" down to "The universe has always existed."
I think this unconfirmed study shows natural selection at work and not evolution. They can only speculate, but they cannot prove that these 30 genes they are looking at "evolved" and by random chance gave these people an edge in just 3,000 years.
I don't think we're saying that the genes evolved in only 3,000 years. Let me post the summary on one of the links someone posted here:Evolution is a random process. Randomly are genes mutated, and randomly and highly improbably are they ever beneficial to the organism. Because they are beneficial, natural selection acts upon what happened by random chance. Evolution by itself is random, coupled with natural selection it is guided. I just don't think in 3,000 years that the extremely improbable mutations required to alter 30+ genes to adapt a population to live in the mountains could occur. Natural selection would best support this, in that those who did not already have the genes to survive in the mountains died and did not pass their genes on (or they moved back to the lowlands).
Right here it says that the genes have been subject to strong selection. But don't forget natural selection is evolution. The fact that the genes exist in the first place means they must have mutated at some point.During the past 100,000 to 200,000 years, anatomically modern humans successfully colonized a diverse range of environments across the planet. Some of the most extreme of these environments are found on the high-altitude plateaus of Central Asia and the Andes. The Tibetan Plateau appears to have been inhabited for ~25,000 years, and permanent settlements have been established at elevations of 3500 to 4500 m (1, 2). Residents of these lofty altitudes descend from a long line of highland ancestors who lived long enough to reproduce in spite of the physiological challenges associated with chronic oxygen deprivation. Thus, studies of indigenous high-altitude residents provide the opportunity to identify genes that may have played a role in hypoxia adaptation. On pages 72 and 75 of this issue, Simonson et al. (3) and Yi et al. (4), respectively, combine genomic and candidate-gene analyses to identify the genetic basis of high-altitude adaptation in Tibetans. Together with another recent analysis (5), the studies reveal that genes in the hypoxia-inducible factor (HIF) oxygen signaling pathway have been subject to strong and recent positive selection in Tibetan highlanders.
You're misunderstanding the second law of thermodynamics, which says the entire entropy in a closed system increases. All it says is that the entropy of the galaxy is increasing, but we have a sun nearby that provides energy to our local system which is capable of increasing its order because of the input of energy.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.
Actually, it should be seen as inevitable that things would develop to be more complex and specialized. With selection removing anything that is not beneficial to an organism, its inevitable that over long periods of time organisms would grow more complex and become better adapted to their environment.
It's like the monkeys typing on a typewriter analogy, over time its inevitable that they will type out something coherent. Same with life, over time its inevitable that something adapted to the environment and complex will develop.
Barrow and Tipler [30] review the consensus among such biologists that the evolutionary path from primitive Cambrian chordates, e.g. Pikaia, to Homo sapiens was a highly improbable event. For example, the large brains of humans have marked adaptive disadvantages, requiring as they do an expensive metabolism, a long gestation period, and a childhood lasting more than 25% of the average total life span. Other improbable features of humans include:
Being the only extant bipedal land (non-avian) vertebrate. Combined with an unusual eye–hand coordination, this permits dextrous manipulations of the physical environment with the hands;
A vocal apparatus far more expressive than that of any other mammal, enabling speech. Speech makes it possible for humans to interact cooperatively, to share knowledge, and to acquire a culture;
The capability of formulating abstractions to a degree permitting the invention of mathematics, and the discovery of science and technology.
Barrow, John D.; Tipler, Frank J. (19 May 1988). The Anthropic Cosmological Principle. foreword by John A. Wheeler. Oxford: Oxford University Press. LC 87-28148. ISBN 9780192821478. The anthropic cosmological principle - Google Books. Retrieved 31 December 2009. Section 3.2
Goshin, the guys who wrote that are mathematicians and cosmologists, not experts in evolution. Tipler is also something of a nut(see his book The Physics of Immortality). Barrow is not quite as nutty,. except as a proponent of ID.
Yes, every time I mention them someone says something like that. Being considered a "nut" by some doesn't necessarily mean you're always wrong... I expect there have been plenty of scientists who were viewed with some disdain at some point who were later found to have at least been right about some things.
But at any rate, they aren't the only ones by far who hypothesize that some or many elements of evolution were improbable. The author of the following article is certainly an evolutionist, and his topic is actually the Great Filter hypothesis in answer to the Fermi Paradox, but a number of his points are relevant on the subject of how improbable certain aspects of evolution might be. It's quite an intresting read, at any rate:
http://www.nickbostrom.com/extraterrestrial.pdf
He is? His degree is in economics. Not quite what I would call a expert in evolution. What is your interest in the Anthropic Principle by the way?
Pardon, I didn't mean he was an evolutionary biologist, but rather than he was not any sort of evolutionary skeptic.
I came across his article while doing some research on various hypotheses relating to the likelihood of life arising on exoplanets, a subject that intrests me.
Are we to limit opinions only to those who are evolutionary biologists? If so, I must excuse myself from the discussion. :mrgreen:
Why? Evolutionary biologists aren't the only people capable of calculating complex probabilities.However, it is probably best to cite works by those who are in the field of evolution, or at least educated in that field.
Why? Evolutionary biologists aren't the only people capable of calculating complex probabilities.
Why? Evolutionary biologists aren't the only people capable of calculating complex probabilities.
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