| Michigan Science Curriculum; We want your feedback...NOT | |
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| Tweet Topic Started: Sep 13 2006, 06:41 AM (3,024 Views) | |
| Corwin | Sep 19 2006, 05:37 AM Post #61 |
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I agree that Creationism should not be taught in schools either. However, there is a considerable amount of controversy about the identification and dating techniques of many of the bones and fossils that were once considered "facts." I certainly think micro and macro adaptations are important things to teach as well. My beef is with the - amino acids - organism - ape - human - linear line of thinking. The evidence there is extremely weak. |
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| fyi | Sep 19 2006, 08:15 AM Post #62 |
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Principal
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I agree with Nancy. Darwin's theory is not about how life began, but how things change and adapt over time. We have scientific evidence to prove that this occurs. Science should be taught in public schools, not religion. IMO, Intelligent Design is a spiritual concept that has religious implications. Religion and Science should not be taught together---although I think the "Church of Scientology" would disagree with me!
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| BoaterDan | Sep 19 2006, 12:15 PM Post #63 |
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That is not proof of evolution, only of the adaptability of species by SOME means. Without empirical experiments to that end it's just conjecture whether or not it was natural selection based evolution. On that note, the "peppered moth" observations from the 50's that we all learned about (and may still be used) as the classic example of proof of natural selection turned out to be apparently nothing of the sort when actually tested empirically. Yet those observations continued to be used as a classic example of the science of evolution, not as a great example of how the scientific method ultimately disproved a widely accepted hypothesis as it should be. That's the problem with a debate that has at its core determinations of what is science and what isn't and rejecting some notions based on those categorizations. |
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| BoaterDan | Sep 19 2006, 12:35 PM Post #64 |
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Principal
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"My kids have not covered this topic yet in school so I have not seen the textbooks. I am surprized that they would state as fact the idea of life coming from the the primoridial sea and organic "ooze" as you call it." I'm not talking about specific discussions of evolution in science class, I'm talking about every book about animals, nature, etc. etc. Frogs have webbed feet because 200,000,000 years ago... The ladybug has black spots because 273,000,000 years ago... I don't have a problem with most of that to a point because I believe in natural selection in general, but one of my kids had a completely asinine book last year that explained everything from the presumption of actually knowing details about bugs that lived 200,000,000 years ago like what color they were or how they selected mates. It's these presumptions that I'm talking about that are everywhere and never questioned so that by the time evolution is specifically discussed it's in the context of just being a fact. "I have even seen some support the idea that life on THIS planet came from extraterrestrial life." And the intelligent design theory would certainly not rule that out as a possibility. That's why I say it's important to separate the ID core from the way it has been adopted by religious leaders and many christians in general. ID is NOT a theological concept people. Which is to say that it is decidedly not about the question of specifically what/who the designer is. It is simply about specific examples of observable organic structures which can't possibly be explained by evolutionary processes and a possible alternative explanation for them. Whether you want to say it's the Judeo-Christian God, some kind of god (whatever that would be), or Tralfamadorians, from a scientific perspective it sure looks like something way ahead of us was messing with the building blocks of life here in some way. That's all. IMO when you observe that something ocurrs in nature 50% one way and 50% another way, but to support life must appear 100% one way or the other in numbers that make the statistical probability a bigger number than we can imagine, it should be common sense that random chance is a suspect explanation at best. The fact that these questions are not even brought up when teaching evolution is an abomination to the scientific method. The point is just that simple and doesn't have anything to do with religion. |
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| fyi | Sep 19 2006, 12:35 PM Post #65 |
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I have to disagree with you on this, BD. Why do things evolve? Does something change in the environment? Does it spontaneously happen for no good reason? Evolution and adaptation go hand in hand. They both mean change. I think evolution is an extremely slow process that happens over time due to adaptation and natural selection. But what do I know?
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| fyi | Sep 19 2006, 01:02 PM Post #66 |
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Principal
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Scientists: Fossils prove that birds evolved from dinosaurs June 24, 1998 Web posted at: 12:32 a.m. EDT (0432 GMT) Researchers believe the fossils represent dinosaurs that are the immediate ancestors of the first birds WASHINGTON (CNN) -- Scientists say a new discovery means dinosaurs are not extinct. An international team of scientists believes two Chinese fossils of feathered dinosaurs -- animals with down-covered bodies, strong legs and stubby arms -- are the strongest evidence yet that birds evolved from dinosaurs. "This shows that dinosaurs are not extinct, but are well-represented by 10,000 species of birds," paleontologist Philip Currie said Tuesday. Although the fossilized dinosaurs are thought to have been capable of running swiftly, flapping feathered wings and fanning out impressive tail feathers, they were unable to actually fly, said Currie, who is curator of the Royal Tyrrell Museum of Paleontology in Canada. The fossils, which were unearthed in the Liaoning province in China, date back more than 120 million years and offer, according to Currie, conclusive proof that birds evolved from dinosaurs, a theory that has been hotly contested for more than 20 years. A team of scientists identified the fossils as two separate species, and their findings were published in National Geographic magazine and the journal Nature. Resembling the earliest known bird The new fossils closely resemble the earliest known bird, called Archaeopteryx, which dates back 140 million to 150 million years. Although the new fossils closely resemble Archaeopteryx in some ways, they lack the precise form of true birds -- in particular the length of wing and design of individual feathers. For this reason, the researchers believe the fossils were true dinosaurs that are the immediate ancestors of the first birds. Feathered fossils 1 min. 50 sec. VXtreme video "They represent a missing link between dinosaurs and birds which we had expected to find," said Ji Quiang, director of the National Geological Museum in Beijing, who worked on the fossils. Both fossils were removed by the Beijing team from a dry lake bed formation in northeast China. The area has earned fame in recent years for containing rich deposits of dinosaur remains. Fast runners, unable to fly A model of what the Caudipteryx may have looked like The two species, called Caudipteryx zoui, or "tail feather," and Protoarchaeopteryx robusta, both were fast runners and were probably unable to fly, judging from the short arms and long legs. Their feathers may have been for insulation or display, Currie said. Protoarchaeopteryx, which was about the size of a modern-day turkey, is the more primitive and earlier of the two fossils, said Mark Norell, who also worked on the fossils. Norell is chairman and associate curator in the department of vertebrate paleontology at the American Museum of Natural History in New York, Feathers covered its body but there is no preserved evidence of wing feathers. Caudipteryx had more plumage, including a generous tail fan. It stood about three feet tall. Both animals closely resemble meat-eating dinosaurs called theropods, Currie said. "These fossils are things we predicted would be there but seriously in my lifetime I never thought we were going to find them," Norell said. One scientist casts doubt Alan Feduccia, an evolutionary biologist at the University of North Carolina, Chapel Hill, said the discoveries are "very interesting," but he said they do not provide immediate and final proof that birds evolved from dinosaurs. He said the new fossils are dated after those of the first bird, suggesting that the fossils could be either feathered dinosaurs or primitive birds that happened to resemble dinosaurs. "The age dates for these things are still unresolved," said Feduccia. "We need to back up and take a closer look at these things before drawing any final conclusions." Philip Currie helped uncover two fossils in northeastern China Currie said there also may be a division between theories on the evolution of feathers and the evolution of flight. It was once thought that they evolved together. He said the feathers on the dinosaurs probably evolved for warmth, suggesting that some of the animals may have been warm-blooded. Flight may have been a later development. Currie said there are two theories for the origin of flight: that fast-running, birdlike animals developed wings that enabled them to lift away from the ground, or that animals living in trees evolved first into gliders, such as the flying squirrel, and then later into true fliers. The two fossils appear to support the ground-to-air theory instead of the tree-to-ground theory. |
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| fyi | Sep 19 2006, 01:14 PM Post #67 |
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Principal
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Why did I post that article? I know it has not been proven that birds evolved from dinosaurs, just thought it was interesting. There are many scientists that do not believe that this is possible.
Did I just prove your point, BD?
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| fyi | Sep 19 2006, 01:41 PM Post #68 |
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Principal
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That may but true, but there is no scientific basis for it. So what is it? Spiritual? Supernatural? |
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| Momforone | Sep 19 2006, 02:19 PM Post #69 |
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Principal
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I want to know where the powers to be @ LPS came from???????????
:lol:
:lol: Something on the lighter side!
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| fyi | Sep 19 2006, 02:45 PM Post #70 |
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Principal
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We don't have a "Theory" for that one, Momofone! :lol: :lol: :lol: Well...maybe we do..... :ph43r: |
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| Livonia Voter | Sep 19 2006, 05:43 PM Post #71 |
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Principal
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Nope the PTA, ie the darker side...;) |
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| jodygirlh | Sep 19 2006, 07:02 PM Post #72 |
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There is some scientific basis for it in that some things cannot be explained by evolution-as mentioned previously in BD's post. BD's comment does go to my original two points though, which are that evolution cannot be proven anymore than ID can (evolution and adaptation are not exactly the same concepts). Further, ID is not a religious theory despite the fact that many christian leaders have jumped on that train. Okay, I'm really done now-good discussion though. |
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| cmic | Sep 19 2006, 07:33 PM Post #73 |
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Please forgive me for saying this, but I really feel that ID is a religious theory called creationism and that Christian Leaders may be trying to get it some more validity by saying it is not religious. It certainly isn't scientific. Now, that being said. I believe in God and believe that all things are possible through him. I just don't know how I feel about ID. |
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| fyi | Sep 19 2006, 07:49 PM Post #74 |
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http://en.wikipedia.org/wiki/Adaptation In evolutionism, a biological adaptation is an anatomical structure, physiological process or behavioral trait of an organism that has evolved over a period of time by the process of natural selection such that it increases the expected long-term reproductive success of the organism. The term adaptation is also sometimes used as a synonym for natural selection, but most biologists discourage this usage. Adaptation can be viewed as taking place over geological time, or within the lifetime of one individual or a group. Not all evolutionary changes are the result of adaptation. |
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| fyi | Sep 19 2006, 08:20 PM Post #75 |
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Principal
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I found this article interesting: http://www.dukenews.duke.edu/2006/01/suzuk...ience_print.htm Researchers Evolve a Complex Genetic Trait in the Laboratory Experiments with hornworms offer important insight into how complex traits involving many genes can abruptly “blossom” in an organism’s evolution. Friday, February 3, 2006 Durham, N.C. -- Duke University biologists have evolved a complex trait in the laboratory -- using the pressure of selection to induce tobacco hornworms to evolve the dual trait of turning black or green depending on the temperature during their development. The biologists have also demonstrated the basic hormonal mechanism underlying the evolution of such dual traits. Natural Sciences Research Their experiments, they said, offer important insight into how complex traits involving many genes can abruptly “blossom” in an organism’s evolution. The researchers -- Professor of Biology Frederik Nijhout and graduate student Yuichiro Suzuki -- published their findings in the Feb. 3, 2006, Science . Their work was funded by the National Science Foundation. The complex traits, or "polyphenisms," they studied are instances in which animals with the same genetic makeup can produce quite different traits, or phenotypes, in different environments. For example, genetically identical ants can develop into queens, soldiers, or workers, according to their early hormonal environment. Or, the same butterfly can assume very different coloration in winter or summer. A kind of polyphenism is also likely at work in mammals -- for example in the seasonal development of antlers or changes in plumage or coat colors, said Nijhout and Suzuki. While biologists have understood the basic machinery underlying polyphenisms, the mystery remained how such complex traits, which involve mutations in multiple genes, could evolve and persist. “It’s long been known that polyphenisms are controlled by hormones, with the brain sensing environmental signals and altering the pattern of hormonal secretions,” said Nijhout. “In turn, these hormonal patterns turn sets of genes on or off to produce different traits. However, we understood only the developmental mechanism, and how it is possible with a single genome in an animal to produce two very different phenotypes,” he said. “There had been theoretical models to explain the evolutionary mechanism -- how selective pressures can maintain polyphenisms in a population, and why they don’t converge gradually into one form or another,” said Nijhout. “But nobody had ever started with a species that didn’t have a polyphenism and generated a brand-new polyphenism. Such a demonstration could offer important insights into the evolutionary mechanism underlying such traits.” In their experiments, Suzuki and Nijhout chose a species of finger-sized tobacco hornworm, Manduca sexta , which normally produces only green larvae. Because a related species, Manduca quinquemaculata , develops black or green larvae when exposed to lower or higher temperatures, the researchers theorized that they could use temperature shocks to evolve a similar polyphenism in M. sexta . Suzuki and Nijhout conducted their experiments on a black mutant form of M. sexta , which is black because of lower production of a key hormone called juvenile hormone. They subjected the black mutant caterpillars to heat during a critical period, and over multiple generations selected for two different lines of mutant caterpillars. One polyphenic line was selected to show increased greenness on heat treatment, and one monophenic line selected to show decreased color change upon heat treatment. After rearing and selecting ten generations of caterpillars, with about 300 caterpillars per generation, the researchers found that they had, indeed, created the two distinct strains. The polyphenic strain would develop a green color at higher temperatures, altering abruptly at a temperature of about 28 degrees C. (83 degrees F.) In contrast, the monophenic strain remained black at all temperatures. The researchers could compare these strains to understand the origin of the polyphenism. Their experiments revealed that it was the level of juvenile hormone in the caterpillars that regulated whether they would turn black or green. For example, by applying a spot of juvenile hormone extracted from a green caterpillar to a black caterpillar during a critical period, Suzuki could produce a green spot on that caterpillar. Also, by tightening a tiny noose around a developing caterpillar’s head to prevent the juvenile hormone -- produced in the head -- from flowing to the rest of the body of the heated polyphenic worm, Suzuki could prevent the caterpillar from turning green. According to Nijhout, the generation of polyphenism in the caterpillar demonstrates an evolutionary phenomenon called “genetic accommodation.” In this process, a mutation in a regulatory pathway such as a hormonal pathway changes the hormonal level to bring it closer to a threshold level that could be affected by environmental variation. Thus, the black mutant hornworm had “dialed-down” levels of juvenile hormone, so that the caterpillar’s color-producing machinery would be more likely to be affected by temperature. By selecting for a temperature-sensitive strain, the researchers established polyphenism in the caterpillar. “Our work is really the first demonstration that genetic accommodation actually can happen,” said Nijhout. “In this case, it happens in the laboratory by artificial selection; but as with all such experiments, we assume that this is a microcosm of what is actually going on in nature.” Nijhout theorized that such “homeostatic” mechanisms that maintain, for example, the color of a caterpillar, can act to mask a great deal of mutations present within the genetic machinery. “Homeostatic mechanisms tend to stabilize a phenotype such as color and, therefore, allow the accumulation of underlying, covert mutations just as an electrical capacitor acts to accumulate charge. And eventually, these mutations could ‘break out’ of that constraint to produce a sudden phenotypic change; and one way for them to break out is for a mutation to happen -- for example, one that alters a hormonal level -- releasing all this variation. “The reason this ‘capacitor’ concept is important in understanding evolution and the origin of complex traits is that the common model is that a new trait gets started by a fortuitous single mutation,” said Nijhout. “And while that likely happens, we believe that another important mechanism involves the accumulation of many mutations in many genes without any apparent effect because they are buffered by a homeostatic mechanism; then all of a sudden one of them alters the homeostatic mechanism and lots of genetic variation suddenly explodes and is revealed as a tremendous increase in the phenotypic variability of the species. This variation then serves as raw material for selection to mold a new adaptive trait. And so that’s why we think these kinds of experiments demonstrate an important novel mechanism for the evolution of novel traits.” In further studies, Nijhout and his colleagues will seek to determine whether the type of evolutionary mechanism they demonstrated in the laboratory also occurs in nature. Also, they will seek to demonstrate the phenomenon of the genetic ‘capacitor,’ in which mutations can accumulate ‘invisibly’ without obviously affecting a trait, and whether natural selection tends to filter out deleterious mutations in such cases. |
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