Analyzing Darwin's Theories Of Sexual Selection

The term "sexual selection" was proposed by Darwin. He contrasted in a sense, natural selection sexual selection because, as he said, sexual selection occurs not as a result of the struggle for existence, as in the case of natural selection and the struggle for the possession of individuals of the same sex. And, as a rule, the struggle between the males for possession of the females. Since then, continuing fierce debate about this phenomenon - sexual selection, and still many researchers, for example, believe that sexual selection does not need to be isolated and does not need to be separated from the natural selection, it's just part of the process.
Darwin realized that many of the characteristics that he had observed in animals, cannot be explained by evolutionary adaptation to external conditions. For example, the luxurious plumage of males of some birds (eg peacock) is clearly non-adaptive, makes owners more vulnerable to predators and requires consumption of more nutrients to maintain the shape and color. Darwin realized that evolution - it is rather a problem of differences in breeding than the differences in survival.
Darwin identified two categories of sexual selection. The first - a contest for the right males mating with the females, sometimes called male-male competition. This kind of competition contributes to the development in the evolution of all the signs that help males to win other males. These include horns, stronger muscles and more intelligent brains. Another form of sexual selection - a choice of female sexual partner. In this case the features that the female prefers males during evolution becoming more