There are more waves than that to be sure. The Inuit arrived in the Americas somewhere around 6000 years ago, and there's some suggestion that Polynesian peoples may have made it to the Americas, though my understanding is that that's not a foregone conclusion.
It is important to note that much of Polynesia was only settled very recently (pre-historically speaking). I may not have the dates correct (it has been a while since I have studied anything Polynesian), but Easter Island was only occupied for a couple of generations (maybe 100-200 years) before any Europeans arrived some 300 years ago. Hawai'i has only been settled for maybe a thousand years, and most of the rest Polynesia was only settled in the last 1-4 thousand years. Thus, while some Polynesians may have made it to the New World, their arrival is not a significant part (if any part at all) of peopling of the New World theories.
That is not to say that possible Polynesian migration to the New World is not an interesting question, only that it really isn't relevant when we are talking about how the New World was settled, and what waves of settlers showed up. That being said, the rest of your post is pretty much spot on, from what little I know.
Carbon dating is actually very accurate for a certain timeframe (say 1k-50k YBP), and the nature of the error bars is pretty well understood (hence, radiocarbon dates are given as a range, rather than a specific year). Even dates for more recent things are accurate, but they lack enough precision to be really useful. For instance, a 100 year old object may be dated to between 500 and 5 years old. That 500 year range is not very precise, though it is dead accurate (as 100 years falls in the range). However, if you have a 12,000 year old object, and the radiocarbon date comes out to a range between 11k and 13k years old, that is an acceptable level of precision.
To address your second point, yes, the ratio of C-14 to other isotopes does change through time. However, it is possible to calibrate that scale through other dating methods. Before I get into that, it is also important to note that most dates are generally given in radiocarbon years. For instance, the first appearance of Clovis peoples in the New World is generally given as 11.5k YBP (i.e. 11,500 years ago). That date is an uncalibrated date, and would be reported as 11.5k radiocarbon years before present. 11.5k radiocarbon years is actually closer to 15-16k calendar, or calibrated years. Now, how do we know this? Well, there are several convergent lines of evidence. First off, we have dates from dendrochronology (i.e. tree rings) that go back a couple of thousand years. If you take several rings from a tree, you can date those rings to calendar year (assuming you have a complete timeline). You can then analyze those rings using radiometric methods. If you know that the ring is 2,403 calendar years old, and you get a radiocarbon date of 1,800-2,000 years old, you have a datapoint for calibration. Collect enough tree rings and radiocarbon dates, and you can begin to calibrate the scale. There are also other methods of calibration, but I am less familiar with them. I think that there are calibrated scales that use ice cores (where you can see yearly snowfall fairly well) that go back a few tens of thousands of years, and there may even be a few historical documents that help us calibrate dates in the last 5-8 thousand years.
That is the definition. I simply left out much of it for the sake of simplicity, and because viable offspring are irrelevant to the current discussion. If Neanderthals and anatomically modern humans did not interbreed, then it doesn't matter whether or not they could have interbred to create viable offspring. African and Indian elephants probably could interbreed to create viable offspring, but they are geographically separate, and do not interbreed, and are, therefore, distinct species.
But, again, how do you define species in plants? Corn and various grasses can interbreed to produce viable seeds. Should corn and Bermuda grass be considered on species? How do you define different species of bacteria or fungus, which reproduce by dividing? Where do you draw the species line with ring species? Should horses and mules be considered different species, even though they are capable, in certain circumstances, of producing viable offspring? What about lions and tigers, which can produce viable offspring, but don't in the wild? Species is a nebulous concept. In the current discussion, if we use the standard definition (i.e. members of two populations can and do interbreed [to produce viable offspring]), then Neanderthals and anatomically modern humans were probably distinct species, because there is no evidence that they did interbreed and produced viable offspring -- in fact, there is no evidence that they interbred at all.
That is, actually, a possible speciation event. Remember, it is "do not/cannot" interbreed, not simply "cannot." If there are geographical or behavioural reasons that members of a population cannot interbreed, then they are generally considered different species. The problem is that species is such a nebulous concept, and there are not clear lines between them. While the lines are clearer in the animal kingdom (plants and microbes are very hard to clearly pin down), there are still things like ring species that muddy the waters in the animal kingdom. So, again, it comes down to how you define "species," and what evidence you require to make the distinction.
It is not so much inconclusive as it is a matter of how you define "species." Generally, among animals, species are distinct populations that do not/cannot interbreed. Because, as you say, we cannot get access to non-osteological anatomical data or behavioural data (beyond inferential data from tools and burials), we are forced to rely upon genetic data to see how well this definition fits. This evidence indicates that the Neanderthal and anatomically modern human lines split before the rise of anatomically modern humans, and that there is no Neanderthal DNA running around today in human populations. If they were the same species (i.e. they were capable of and did interbreed), we would expect to see Neanderthal DNA in the modern line of humans, and we would not expect the split to be so far back. This would seem to imply that H. sapiens and H. neanderthalis are/were different species, about as conclusively as anything in genetics/paleo-genetics.
That being said, nothing in science is ever entirely conclusive -- everything is tentative.
While I would certainly like to believe that, and held to that belief for many years, mtDNA and nuclear DNA evidence seems to point in the other direction. Certainly, there is always more evidence that can be collected, but most of the good genetic evidence indicates that H. sapiens and H. neanderthalis were/are distinct, though related, species. See, for example, Sequencing and Analysis of Neanderthal Genomic DNA.
Meanwhile the statistician is running from room to room lighting fires -- he needed a larger sample.
Also, given an empty ice-bucket on the dresser, the sink in the hotel bathroom, and a burning trashcan, how does a mathematician put out the fire? Like any ordinary person, he grabs the ice-bucket, runs to bathroom, fills the bucket with water from the sink, and pours the water into the trashcan, thus putting out the fire. Now suppose that the ice-bucket is already full -- how does the mathematician put out the fire? He grabs the ice-bucket, runs to the sink, empties it, and returns it to the dresser. The problem has now been reduced to one that has been previously solved.
In Greco-Roman wrestling, athletes are generally sorted by weight, because it would be unfair for a very heavy person to wrestle a very small person. In horse racing, there are limits on jockey's weights. There are many sports where the main organizer places arbitrary limits on the competitors weight, height, or other physical characteristics in order to level the playing field. If you have a problem with the way in which an organization limits its athletes, I am not the person you should speak to. I honestly don't care that much -- I am just reporting the facts. If you don't like the 16 year old age limit in gymnastics, maybe you should take it up with FIG.
Height isn't the only advantage. There is also weight, more flexible bones, a lack of breasts and widened hips. That being said, I don't know why FIG determined to use an age limit. Perhaps they should have used a height/weight limit? You would have to take it up with them.
Because in swimming, there is no advantage to being younger (in fact, there may be a disadvantage, in that you are shorter and not as heavily muscled). In gymnastics, there is an advantage to being smaller. It allows you to performs the maneuvers far more easily. The age of 16 may be arbitrary (though it will probably have the effect of weeding out most pre-pubescent competitors), but it does level the playing field.
It actually has more to do with the fact that being smaller makes it easier to perform. Younger, smaller athletes have an advantage. The rule seeks to prevent that advantage from unleveling the playing field.
I was going to suggest Darwinia and Uplink, but he specifically mentioned no multiplayer games in the introduction, so I don't suppose that DEFCON counts.;)
I would suggest that you read through these essays by Ms. Le Guin. The sad fact is that authors rarely have any input in the film-ification of their work.
Not to go entirely off topic, but evolution is about change in gene frequencies in a population over time. Natural selection is one mechanism of evolution. Artificial selection, i.e. human breeding, is another mechanism. It is perfectly appropriate and correct to say that wolves and golden retrievers evolved from the same parent population. Also, if seedless grapes cannot reproduce, why are there so many seedless grape plants? They cannot reproduce sexually, but they can reproduce by cloning. They are not "stuck," just evolving much more slowly than they would be if they could reproduce sexually. Or do you consider one celled organisms that reproduce by splitting to be "stuck?" In that case, can you explain to me how the E. coli in a recent experiment managed to metabolize citrate?
I hate to break this to you, but a 747 is not rated for aerobatics. It doesn't have the power for the kind of vertical climb you are talking about, and the wings would fall off if you tried the other stunts you suggest. There is a reason that the NASA's "Vomit Comet" was as expensive as it was -- it is not a bog standard plane, and was specially designed and reinforced to take the Gs.
You entirely missed the point. Either that, or you are trolling (which seems likely, given that you are posting anonymously). You need to memorize some things -- basic arithmetic, spelling, &c. (honestly -- do you sound out every word phonetically when you spell? -- given that your spelling is spot on, I imagine that you don't). You have to have some facts before you can start making abstractions, or give meaning to those abstractions. To paraphrase the above, critical thinking is about connecting the dots, while memorization is about having the dots to connect in the first place. No one is suggesting that children should not be taught abstractions or critical thinking. Rather, it is being suggested that some level of memorization is necessary in order to facilitate higher level abstractions.
I don't think that anyone was necessarily suggesting that one must spend time drilling in order to memorize. For me, that was the easiest way to memorize things, but others may have other methods. The point is that some amount of memorization is necessary. You have to have information before you can start drawing connections between the individual pieces of information. At some level, that must be memorized.
You claim that you have not memorized the multiplication tables. Can you tell me what 8 times 7 is without the use of a calculator or counting on your fingers? If you can, you have memorized the multiplication table.
Learning is about making connections. Memorizing is about having the bits in place to connect. Education requires both.
That is, I think, one of the most eloquent and succinct comments I have seen about memorization, and its role in education. Do you mind if I use it in the future?
Honestly, excavation never exited me that much. I prefer survey. However, in terms of excavation, provenience is everything -- if you don't know where something came from, it has less meaning. Thus, archaeologists are as anal about their 1 meter units (or even smaller units) as chemists are about their titrations (or whatever chemists do).
But that specification of the separation of church and state is with reference to creation or forced following of a state/govt. religion. It is not there to prohibit the discussion of religion or religious thoughts.
If a teacher is teaching a religious alternative to evolution, they are in violation of the 1st amendment. The Supreme Court has repeatedly asserted that teachers in public schools instructing children in religion is a government establishment of religion, and a violation of the establishment clause. It is perfectly fine to discuss religion in a comparative religion or social studies class of some sort, but it is completely inappropriate to teach religion as fact, or as an alternative to science, in a science class.
Slashdot Mirror
It is important to note that much of Polynesia was only settled very recently (pre-historically speaking). I may not have the dates correct (it has been a while since I have studied anything Polynesian), but Easter Island was only occupied for a couple of generations (maybe 100-200 years) before any Europeans arrived some 300 years ago. Hawai'i has only been settled for maybe a thousand years, and most of the rest Polynesia was only settled in the last 1-4 thousand years. Thus, while some Polynesians may have made it to the New World, their arrival is not a significant part (if any part at all) of peopling of the New World theories.
That is not to say that possible Polynesian migration to the New World is not an interesting question, only that it really isn't relevant when we are talking about how the New World was settled, and what waves of settlers showed up. That being said, the rest of your post is pretty much spot on, from what little I know.
Carbon dating is actually very accurate for a certain timeframe (say 1k-50k YBP), and the nature of the error bars is pretty well understood (hence, radiocarbon dates are given as a range, rather than a specific year). Even dates for more recent things are accurate, but they lack enough precision to be really useful. For instance, a 100 year old object may be dated to between 500 and 5 years old. That 500 year range is not very precise, though it is dead accurate (as 100 years falls in the range). However, if you have a 12,000 year old object, and the radiocarbon date comes out to a range between 11k and 13k years old, that is an acceptable level of precision.
To address your second point, yes, the ratio of C-14 to other isotopes does change through time. However, it is possible to calibrate that scale through other dating methods. Before I get into that, it is also important to note that most dates are generally given in radiocarbon years. For instance, the first appearance of Clovis peoples in the New World is generally given as 11.5k YBP (i.e. 11,500 years ago). That date is an uncalibrated date, and would be reported as 11.5k radiocarbon years before present. 11.5k radiocarbon years is actually closer to 15-16k calendar, or calibrated years. Now, how do we know this? Well, there are several convergent lines of evidence. First off, we have dates from dendrochronology (i.e. tree rings) that go back a couple of thousand years. If you take several rings from a tree, you can date those rings to calendar year (assuming you have a complete timeline). You can then analyze those rings using radiometric methods. If you know that the ring is 2,403 calendar years old, and you get a radiocarbon date of 1,800-2,000 years old, you have a datapoint for calibration. Collect enough tree rings and radiocarbon dates, and you can begin to calibrate the scale. There are also other methods of calibration, but I am less familiar with them. I think that there are calibrated scales that use ice cores (where you can see yearly snowfall fairly well) that go back a few tens of thousands of years, and there may even be a few historical documents that help us calibrate dates in the last 5-8 thousand years.
That is the definition. I simply left out much of it for the sake of simplicity, and because viable offspring are irrelevant to the current discussion. If Neanderthals and anatomically modern humans did not interbreed, then it doesn't matter whether or not they could have interbred to create viable offspring. African and Indian elephants probably could interbreed to create viable offspring, but they are geographically separate, and do not interbreed, and are, therefore, distinct species.
But, again, how do you define species in plants? Corn and various grasses can interbreed to produce viable seeds. Should corn and Bermuda grass be considered on species? How do you define different species of bacteria or fungus, which reproduce by dividing? Where do you draw the species line with ring species? Should horses and mules be considered different species, even though they are capable, in certain circumstances, of producing viable offspring? What about lions and tigers, which can produce viable offspring, but don't in the wild? Species is a nebulous concept. In the current discussion, if we use the standard definition (i.e. members of two populations can and do interbreed [to produce viable offspring]), then Neanderthals and anatomically modern humans were probably distinct species, because there is no evidence that they did interbreed and produced viable offspring -- in fact, there is no evidence that they interbred at all.
That is, actually, a possible speciation event. Remember, it is "do not/cannot" interbreed, not simply "cannot." If there are geographical or behavioural reasons that members of a population cannot interbreed, then they are generally considered different species. The problem is that species is such a nebulous concept, and there are not clear lines between them. While the lines are clearer in the animal kingdom (plants and microbes are very hard to clearly pin down), there are still things like ring species that muddy the waters in the animal kingdom. So, again, it comes down to how you define "species," and what evidence you require to make the distinction.
It is not so much inconclusive as it is a matter of how you define "species." Generally, among animals, species are distinct populations that do not/cannot interbreed. Because, as you say, we cannot get access to non-osteological anatomical data or behavioural data (beyond inferential data from tools and burials), we are forced to rely upon genetic data to see how well this definition fits. This evidence indicates that the Neanderthal and anatomically modern human lines split before the rise of anatomically modern humans, and that there is no Neanderthal DNA running around today in human populations. If they were the same species (i.e. they were capable of and did interbreed), we would expect to see Neanderthal DNA in the modern line of humans, and we would not expect the split to be so far back. This would seem to imply that H. sapiens and H. neanderthalis are/were different species, about as conclusively as anything in genetics/paleo-genetics.
That being said, nothing in science is ever entirely conclusive -- everything is tentative.
"Neanderthal" is the correct spelling. However, it is German, so it is pronounced as you spell it.
While I would certainly like to believe that, and held to that belief for many years, mtDNA and nuclear DNA evidence seems to point in the other direction. Certainly, there is always more evidence that can be collected, but most of the good genetic evidence indicates that H. sapiens and H. neanderthalis were/are distinct, though related, species. See, for example, Sequencing and Analysis of Neanderthal Genomic DNA.
Meanwhile the statistician is running from room to room lighting fires -- he needed a larger sample.
Also, given an empty ice-bucket on the dresser, the sink in the hotel bathroom, and a burning trashcan, how does a mathematician put out the fire? Like any ordinary person, he grabs the ice-bucket, runs to bathroom, fills the bucket with water from the sink, and pours the water into the trashcan, thus putting out the fire. Now suppose that the ice-bucket is already full -- how does the mathematician put out the fire? He grabs the ice-bucket, runs to the sink, empties it, and returns it to the dresser. The problem has now been reduced to one that has been previously solved.
In Greco-Roman wrestling, athletes are generally sorted by weight, because it would be unfair for a very heavy person to wrestle a very small person. In horse racing, there are limits on jockey's weights. There are many sports where the main organizer places arbitrary limits on the competitors weight, height, or other physical characteristics in order to level the playing field. If you have a problem with the way in which an organization limits its athletes, I am not the person you should speak to. I honestly don't care that much -- I am just reporting the facts. If you don't like the 16 year old age limit in gymnastics, maybe you should take it up with FIG.
Height isn't the only advantage. There is also weight, more flexible bones, a lack of breasts and widened hips. That being said, I don't know why FIG determined to use an age limit. Perhaps they should have used a height/weight limit? You would have to take it up with them.
Because in swimming, there is no advantage to being younger (in fact, there may be a disadvantage, in that you are shorter and not as heavily muscled). In gymnastics, there is an advantage to being smaller. It allows you to performs the maneuvers far more easily. The age of 16 may be arbitrary (though it will probably have the effect of weeding out most pre-pubescent competitors), but it does level the playing field.
It actually has more to do with the fact that being smaller makes it easier to perform. Younger, smaller athletes have an advantage. The rule seeks to prevent that advantage from unleveling the playing field.
Didn't watch to the end of the video, did you? They showed a couple of other faces on the actress.
I was going to suggest Darwinia and Uplink, but he specifically mentioned no multiplayer games in the introduction, so I don't suppose that DEFCON counts. ;)
Han shot before Hans.
I would suggest that you read through these essays by Ms. Le Guin. The sad fact is that authors rarely have any input in the film-ification of their work.
Not to go entirely off topic, but evolution is about change in gene frequencies in a population over time. Natural selection is one mechanism of evolution. Artificial selection, i.e. human breeding, is another mechanism. It is perfectly appropriate and correct to say that wolves and golden retrievers evolved from the same parent population. Also, if seedless grapes cannot reproduce, why are there so many seedless grape plants? They cannot reproduce sexually, but they can reproduce by cloning. They are not "stuck," just evolving much more slowly than they would be if they could reproduce sexually. Or do you consider one celled organisms that reproduce by splitting to be "stuck?" In that case, can you explain to me how the E. coli in a recent experiment managed to metabolize citrate?
I hate to break this to you, but a 747 is not rated for aerobatics. It doesn't have the power for the kind of vertical climb you are talking about, and the wings would fall off if you tried the other stunts you suggest. There is a reason that the NASA's "Vomit Comet" was as expensive as it was -- it is not a bog standard plane, and was specially designed and reinforced to take the Gs.
You entirely missed the point. Either that, or you are trolling (which seems likely, given that you are posting anonymously). You need to memorize some things -- basic arithmetic, spelling, &c. (honestly -- do you sound out every word phonetically when you spell? -- given that your spelling is spot on, I imagine that you don't). You have to have some facts before you can start making abstractions, or give meaning to those abstractions. To paraphrase the above, critical thinking is about connecting the dots, while memorization is about having the dots to connect in the first place. No one is suggesting that children should not be taught abstractions or critical thinking. Rather, it is being suggested that some level of memorization is necessary in order to facilitate higher level abstractions.
I don't think that anyone was necessarily suggesting that one must spend time drilling in order to memorize. For me, that was the easiest way to memorize things, but others may have other methods. The point is that some amount of memorization is necessary. You have to have information before you can start drawing connections between the individual pieces of information. At some level, that must be memorized.
You claim that you have not memorized the multiplication tables. Can you tell me what 8 times 7 is without the use of a calculator or counting on your fingers? If you can, you have memorized the multiplication table.
That is, I think, one of the most eloquent and succinct comments I have seen about memorization, and its role in education. Do you mind if I use it in the future?
Honestly, excavation never exited me that much. I prefer survey. However, in terms of excavation, provenience is everything -- if you don't know where something came from, it has less meaning. Thus, archaeologists are as anal about their 1 meter units (or even smaller units) as chemists are about their titrations (or whatever chemists do).
Hey! I resemble that remark!
:(
Anyway, I stopped using toothpicks years ago while excavating. Now I use a toothbrush! And you have the audacity to call me anal retentive.
If a teacher is teaching a religious alternative to evolution, they are in violation of the 1st amendment. The Supreme Court has repeatedly asserted that teachers in public schools instructing children in religion is a government establishment of religion, and a violation of the establishment clause. It is perfectly fine to discuss religion in a comparative religion or social studies class of some sort, but it is completely inappropriate to teach religion as fact, or as an alternative to science, in a science class.