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What is Darwin's Theory of Natural Selection?


Charles Darwin was an English naturalist, geologist, and biologist. He is best known for his theory of natural selection and as well as his contributions to his science of the evolution. His theory consists of five components: "Variation", "Inheritance", "Selection", "Time", and "Adaption".





Phenotypic variation exists among individuals. Such variation can include sets of random mutation and copying errors due to heritable variation. When organisms reproduce, many characteristics are inherited and passed from parent to offspring. Those individuals that have better heritable traits in an environment will survive the most and those who don't have the necessary heritable traits for that environment will not survive. Over time, the best genetic fitness for the environment will produce an offspring that can successfully outweigh others and the population will expand.




On the Galapagos Islands, Darwin observed that each of the thirteen species had shared a common ancestor as they resembled one another. This could only mean one thing: The groups of finches had been isolated on separate islands for many generations. Darwin concluded that each group would have been exposed to a different environment. The Finches beaks were selected for over generations and so the birds with the favored traits survived and reproduced effectively among other birds. Moreover, the birds were identical to one another and their beaks had adapted to the type of food they ate.

One type of finch Darwin discovered was the "Geospiza magnirostris" also known as the large ground finch on the Galapagos Islands. The birds are large and in beak size. The birds have large and short beaks to crack large seeds and nuts. They are "the least concerning" because they can adapt efficiently. Another bird he discovered was the "Certhidea olivesea" also known as the green warbler finch. These birds are the smallest out of all the Finches and have the thinnest beaks. They eat insects, ample amount of daisy trees, and is

considered vulnerable when it comes to adapting in the environment.




In Darwin's time, Jean Baptiste Lamarck theory's was the prevailing notion of evolution. Lamarck's theory stated that traits and organism gained in their lifetime through lifestyle, exercise, and habitat would be passed on to their offspring. For example, If a person rigorously swam throughout their lifetime, their lungs would be bigger due to increase use: Lamarckism posit's that the person's offspring will have larger lungs.

The study of genetics proved Lamarckism wrong, but Darwins's theory was congruent with genetics even though at the time Darwin did not understand how traits were passed on. Many rebuttals have opposed Darwin's theory in the past century. The underlying principles of natural selection remain true despite the fact that evolutionary biology, genetics, and science in general have advanced exponentially since Darwin's time.



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References:

“Evolution: Frequently Asked Questions.” PBS, Public Broadcasting Service, www.pbs.org/wgbh/evolution/library/faq/cat01.html.

GalapagosIslands.com. “Home.” Who Is Charles Darwin and What His Theory Took from Galapagos?, www.galapagosislands.com/info/history/charles-darwin.html.

“Great Natural Selection Simulation Using the Example of Peppered Moths.Www.techapps.net/Interactives/PepperMoths.swf: Peppered Moth, Moth, Insects.” Pinterest, www.pinterest.com/pin/474566879463942993/.

“How Does Natural Selection Work? 5 Basic Steps (VISTA): AMNH.” American Museum of Natural History, www.amnh.org/exhibitions/darwin/evolution-today/natural-selection-vista.

Population and Evolutionary Genetics, www.ndsu.edu/pubweb/~mcclean/plsc431/popgen/popgen5.htm.







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