Evaluation on the Theory of Evolution

The theory of evolution was created to explain the existence of different species and the variations within one. The theory states that the change in one organism's genetic makeup in a population over time occurred due to natural selection, mutations, and more. It includes ideas such as adaptation (the change in an organism's structure/behavior to become more suited for their environment), natural selection (otherwise known as survival of the fittest), and descent from a common ancestor (all organisms found on Earth have descended from a common ancestor). These ideas have derived from several biologists such as Jean Lamarck, Alfred Russel Wallace, and Charles Darwin. Although their thoughts differ from one another, their knowledge had greatly contributed to science, specifically in the study of evolution.

Jean Lamarck was one of the first scientists to publish his work on the study of adaptations made by all of the organisms found on Earth as an effort to survive and be better suited for their environment. It should first be recalled that adaptations are the changes made by an organism to have a better chance at survival in their environment. The first thought about how those adaptations came about were not about genetics, but an organism's behavior instead. During Lamarck's time, the idea of genetics was not yet perfected. Lamarck stated a new environment would lead to changes in one's activity resulting in "the use of some one part in preference to some other part, and in some cases the total disuse of some part no longer necessary." This led him to think that by the use or ignorance of one part or organ of an organism that part will either be strengthened or extinguished (it will no longer have any use for it). For example, he explained that a giraffe developed its long neck through its constant efforts to reach the leaves of tall trees.

As time went on and new studies and experiments were performed, Alfred Russel Wallace began to question Lamarck's theory behind evolution. He agrees that adaptations do exist among the animal and plant kingdom, but he does not believe that they were produced due to an animal's attempt at increasing the development of their own organs. He described the changes and variations found in a species to be a result of a struggle for existence. Wallace described this process as one where "the weakest and least perfectly organized must always succumb." This process could be described as survival of the fittest, or in other words, natural selection. Wallace believed that the variations found due to genetics will affect their ability to survive, because there is not enough food supply to feed all of the organisms. Therefore, the weakest will die off, taking their bad traits with them. These variations could be as simple as a change in color for camouflage against predators, or the power/dimensions of their limbs to help them move faster. As stated by