Charles Darwin's Theory Of Evolution By Natural Selection

The origin of the living creatures has claimed the attention of the scientists for centuries until Charles Darwin explained it in a clear way. From 1831 to 1836; Charles Darwin was on a survey expedition in South America, Australia and the Southern tip of Africa. During this journey, Darwin began to see exciting patterns in the distribution of the organisms. Therefore, he found a new branch of life science which is called evolutionary biology. According to Khan Academy website evolution means that the populations and species of organisms change over time. In 1859 in England, Charles Darwin introduced his divisive theory of evolution, which was developed during his study of Galapagos Finches, in his book ‘The origin of species’. Darwin claimed

Instead of looking at bears, he should have instead been looking at cows and hippopotamuses.” (Than, 2015). The origin of whales is one of the best examples for the evolution by natural selection.

Nowadays there are many transitional fossils found proving this theory. In 1994 paleontologists found the fossilized remains of Ambulocetus natans, an animal whose name means "swimming-walking whale". From this fossil it was found that this animal had fingers and small hooves but it also had big hint feet, this proves clearly that this animal was adapted to swim and to move on the lands. Than said, “When it swam, the ancient creature moved like an otter, pushing back with its hind feet and undulating its spine and tail”. It is believed that this animal and the whales have common ancestors.

As Zimmer stated in his book “The Tangled Bank”, (2010). In 1860s paleontologists found a specimen of Archaeopteryx, the oldest bird known, it had feathers and tail like birds; it also had hands, shoulder girdles, pelvis, and feet like the dinosaurs; it also had teeth like the reptiles, which made the paleontologists classify it as intermediate between birds and reptiles. In 1970s paleontologists found that Archaeopteryx shares many features with Theropod dinosaurs, therefore Theropod dinosaurs are the ancestors of the

These changes are called mutations. "Mutations are basically the raw material on which evolution acts," Pobiner said. Errors in DNA cause the mutations. Mutations most of the time is harmful but it has a small probability to be advantageous. If it is advantageous, the next generation will have it. Natural selection chooses the species that have these advantageous mutations over the harmful ones’. "Mutations are random, but selection for them is not random," Pobiner said. Genetic changes can produce a new species over a long time if these species