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Charles Darwin and the Theory of Evolution Help

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By — McGraw-Hill Professional
Updated on Aug 30, 2011

Introduction to Charles Darwin and the Theory of Evolution

“How did all these different types of living organisms come to replace or join each other over time? What complicated process seems to be responsible?” you might well ask. The biological answers are: evolution and the process called natural selection .

Evolution

Evolution means “a process of rolling out,” a gradual process of developing or unfolding. In a biological sense, evolution can be considered a gradual unfolding or development of particular patterns of Biological Order, over long periods of time. These patterns of Biological Order are reflected in the body structures and functions of particular living organisms. “Okay, I see,” you may persist, “But what process determines which patterns of Biological Order survive, which patterns become modified, or which patterns (like that of the dinosaurs) become extinct?

Darwin and the Theory of Evolution

Enter Charles Darwin, an English scientist who stated his Theory of Evolution by Natural Selection. Darwin wrote an important book, The Origin of Species by Natural Selection (1859), that explained the fundamental ideas behind this theory. For five years (1831–1836), Darwin sailed around the world on a ship called the Beagle. He spent countless hours collecting fossils and living creatures along the coastline of South America, and in observing strange creatures only found in a set of tiny Galapagos Islands. He concluded that particular groups of organisms adapted themselves (over long periods of time) to particular types of habitats. Since habitats widely differed, he reasoned, so do the organisms that have adapted themselves to these different habitats. By adaptation , it is meant that particular patterns of Biological Order are more “fit” or “appropriate” for certain habitats than are other patterns. And the individual organisms having these more “fit” or “appropriate” patterns were more likely to reproduce themselves. Hence, their particular patterns of Biological Order would be passed on to succeeding generations of offspring. This produces, in a sense, a “survival of the fittest,” or a “natural selection.” The “fittest” (most efficiently adapted) organisms to a particular habitat are the ones that tend to survive and pass their patterns of Biological Order on to their offspring. Only the “most fit” are “selected naturally” to survive and reproduce within a certain habitat.

Charles Darwin supported his theory with many commonsense observations. For example, he cited the seasonal color changes in the feathers of the ptarmigan ( TAR -muh-gun), a type of wild grouse found in cold and mountainous regions. Most ptarmigans he observed had brown spotted feathers in the summer, followed by a dramatic change in color pattern to all-white feathers during the winter. However, a few individual birds did not change their brown spotted feathers to white in wintertime. They were soon “naturally selected against” – easily seen and eaten by hungry bobcats or other predators roaming the frozen white landscape.

Darwin expanded this natural selection idea to explain the evolution or extinction of entire species of organisms. Evidence is still being accumulated to support this general concept, even today.

Practice problems for these concepts can be found at:  From Dawn To Darwin Evolution Test

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