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Evolution - To What Degree?
Mutations create variety in a population, and Natural Selection culls out the unfavorable results. But does this process lead to macro evolution? or micro evolut…
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Evolution - To What Degree?

Mutations create variety in a population, and Natural Selection culls out the unfavorable results. But does this process lead to macro evolution? or micro evolution? Let's check it out.British peppered mothSpecies can and do change over time. At least some of them do. One historical example is the British peppered moth. This variety of moth has made its home in Manchester, England for, well, as far back as anyone can remember. They sport a distinctive light speckled grey coloration on their wings. They perch on trees much the same color as themselves, thereby blending in nicely with their background.Back in the 1840's, Manchester was developing into a major center of British industry. Factories blackened the local vegetation with soot and other pollutants. Against the dark soot covered trees, the lightly covered pepper moths stood out like beacons for bird predators. As you can well imagine, the moth population plummeted. That, however, is not the end of the story.By 1848, darker colored peppered moths began showing up. By the middle of the century, the darker variety had almost completely replaced the lighter pigmented forms in the polluted areas. In unpolluted areas, lighter colored pepper moths remained common. What do you make of it?Evolutionists point to it as a good example of natural selection in action. If you read a book on evolution, you are likely to run across the peppered moth as proof of their theory. But when you think it over, it really doesn't prove much of anything.Peppered moths can vary anywhere from jet black to almost white or any range of shades in between. If lighter shades are suddenly more vulnerable, certainly, darker shades will predominate. But for all practical purposes, they are still the same old pepper moths they always were.They didn't gain any new organ, nor did they lose any old one. All we find is a change in the proportion of colors, and even that is temporary. Once the pollution cleared up, the population returned to its predominate peppered light grey look. Was there any permanent change? No. Was there any "evolution?" Certainly not.Breeding programsBreeding programs are similar dead end tales. Breeders choose chickens that produce larger eggs, cows that yield more milk, and corn with higher protein content. But sooner or later breeders run into a natural barrier. Chickens can produce eggs only so large, cows can only give so much milk. Further genetic manipulations prove useless.In the last century, breeders improved the quality of sheep's wool and raised the level of sugar in beets from 6 to 15 percent. Then it reached its natural limit. Every breeder knows that selective "improvements" whether plants or animals can only go so far. Furthermore, if you discontinue the artificial selection, the "improved" traits will quickly revert back to what they were before the experiment began. As far as evolution is concerned, it's just another potential example that doesn't pan out.InsecticidesWhat about insects? Don't they develop resistance to pesticides such as DDT? Isn't this an example of natural selection? Whenever a new insecticide is introduced, the first few applications are very encouraging. A small amount kills a lot of pests. Nevertheless, in a large population of insects, you can count on a few to be genetically immune to the chemical spray.Those favored pests will multiply and gradually replace those killed by the insecticide. Consequently, the same chemicals will become less and less effective over time. Resistance to one or more pesticides has been recorded in more than 100 species. What has changed? A population of insects, which had a few individuals genetically immune to a particular pesticide, has been replaced by a population in which all, or nearly all, are immune to the same pesticide.Even that minor change is not permanent. Discontinue the pesticides and the insects tend to revert back to what they were before. Once more, no lasting change. And no evolution has occurred.Bacteria and AntibioticsThe same story is repeated with bacteria and antibiotics. New antibiotics tend to destroy the vast majority of bacteria. Some are immune. They survive, reproduce, and replace the old strain. When the antibiotic is discontinued, the bacteria eventually revert back to their old susceptible strain. Permanent change does not occur. Of course that is lucky for us. We can use the same antibiotic to destroy most of the bacteria again.About now you might be wondering if Natural Selection ever works as advertised. The answer may be found on the Galapagos Islands.Darwin's FinchesCharles Darwin collected 13 species of finches on his visit to the Galapagos Islands. The birds had an uncanny resemblance to one another. In fact, the only noticeable differences were their size and beaks. Why different beaks? Darwin observed that the specialized beaks allowed the birds to feed on different foods.Those with short stout beaks were capable of cracking tough seeds, while the ones with smaller beaks could handle the easier-to-crack seeds. One species had a long thin beak and used it for eating insects. Still another group with a different beak used cactus needles to poke grubs out of cracks in wood. 共2页: 上一页 1 [2] 下一页

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