Natural Selection And Variation: Polar Bear, Peppered Moth

Natural selection was first proposed by Darwin. Natural selection and mutation are always taking place together. They are the basic process of evolution. Natural selection means those organisms that fit in theirs living environment will be survive. There are three kinds of mutations: positive, negative or neutral. Natural selection is always going to decide a mutation. Ether it is positive, negative or neutral. Here are three examples of positive mutation: Polar bear, peppered moth, and giraffe. Polar bears live at the North Pole. A lot of people think that polar bear hair is white. But in fact they are not. Their furs are hollow and transparent. But because of theirs living environment, their hair looks a like white colour. When Earth …show more content…
They are some moths with some black spots on light grey wings. Because of the pollution from the factory, those forest they living in become darker. This change led to increase the proportion of black peppered moths. That is because those grey moths in pollution environmental are visible and easy to pick up. But those dark moths are not easy to found because of their body colour. So most of them survived. Because of that, the number of black peppered moths increased. And the number of grey peppered decreased. The reason this happened is because in darker environment black moth will be harder to pick up than the grey moth. Because of this change in population of moth, there was a mutation take place. "It is a big breakthrough as far as peppered moths' industrial melanism are concerned" said Laurence Cook. The genes in their body that controls their body colour had changed. Black colour in their genes become dominate. So we can say that moth's body colour change were affected by the external conditions. Those moth can fit into the environment so they can keep alive and pass their genes alone. It is the result of natural selection under the action of