Charles Darwin was unable to definitively prove evolution through natural selection but it was his belief and he had many strong arguments in support of evolution through natural selection. He describes his book as “one long argument” and in his final chapter begins to summarize his supporting points for evolution through natural selection. In his final chapter Recapitulation and Conclusion he discusses heritable traits that favor survival, causing the traits to increase in frequency over generations. He also discusses how some traits among species are disappearing because of their lack of importance as the species progresses through time. He uses the example of a calf, stating, “The calf, for instance, has inherited teeth, which never cut through the gums of the upper jaw, from an early progenitor having well- developed teeth; and we may believe, that the teeth in mature animals were reduced, during successive generations, by disuse or by the tongue palate having been fitted by natural selection to browse without their aid; whereas the calf, the teeth have been left untouched by selection or disuse, and on the principle of inheritance at corresponding ages have been inherited from a remote period to the present day” (Darwin, 502).
I think that one of the most convincing arguments from Darwin’s last chapter revolve around his main theory of natural selection. I think that it is very reasonable to believe that unused traits over generations will start to fade away, meanwhile adaptations will be made that aid in the given animals survival. The inferior members of the same species will die out, leaving only the more superior ones to reproduce. Another key point that he emphasizes, and that I feel is an extremely important aspect is how slow the process of evolution is. Darwin explains, “As natural selection acts solely by accumulating slight, successive, favorable variations, it can produce no great or sudden modifications; it can act only by very short and slow steps” (Darwin 492). By emphasizing how slow the process of evolution is, the “why can’t I see evolution happening right now” statement will never be a valid argument against his theory.