Comparing Darwin And Russel Wallace's Theory Of Natural Selection

Charles Darwin and Alfred Russel Wallace co-discovered natural selection and are important figures regarding evolution. Despite the fact that they agreed on many features of natural selection, they had several disagreements, including the nature of hybrid sterility (the inability or decreased probability of an organism that is a cross between two different species to reproduce), sexual selection, and the origins of the human brain and its intellectual ability. Wallace believed that sterility was disadvantageous to individuals, but that it was advantageous to groups, whereas Darwin believed that sterility was disadvantageous to both individuals and groups. Wallace regarded male/male competition not as sexual selection, but as natural selection and disregarded the idea of female choice, while Darwin believed that sexual selection, including female choice, was a mode of selection that modified “one sex in its functional relations to the other sex” (Darwin). Wallace believed that a higher power guided human evolution with the intent of allowing humans to contemplate morals, truth, and other intellectual

Darwin’s view is as follows. Suppose that two different species A and B can produce hybrids, AB, that are less fit than their parents. It cannot be to the advantage to the individual hybrids to be sterile because sterile organisms cannot reproduce and thus pass on their genes. It cannot be to the advantage of the parents A and B to produce sterile hybrids since their genes are not able to be passed on by sterile offspring. Once sterility has arisen, it is to the advantage of A and B to develop an aversion to mating so they do not waste their resources on futile mating efforts. Sterility does not refer to a selective advantage, rather partially sterile organisms are less fit and thus selected