History and Application of The Theory
The theory of sexual selection was first proposed by Charles Darwin in his book The Origin of Species, though it was primarily devoted to natural selection. A later work, The Descent of Man and Selection in Relation to Sex dealt with the subject of sexual selection exhaustively, in part because Darwin felt that natural selection alone was unable to account for certain types of apparently non-competitive adaptations, such as the tail of a male peacock. He once wrote to a colleague that "The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!" His work divided sexual selection into two primary categories: male-male competition (which would produce adaptations such as a Bighorn Sheep's horns, which are used primarily in sparring with other males over females), and cases of female choice (which would produce adaptations like beautiful plumage, elaborate songs, and other things related to impressing and attracting).
Darwin's views on sexual selection were opposed strongly by his "co-discoverer" of natural selection, Alfred Russel Wallace, though much of his "debate" with Darwin took place after Darwin's death. Wallace argued that the aspects of it which were male-male competition, while real, were simply forms of natural selection, and that the notion of "female choice" was attributing the ability to judge standards of beauty to animals far too cognitively undeveloped to be capable of aesthetic feeling (such as beetles).
Wallace also argued that Darwin too much favored the bright colors of the male peacock as adaptive without realizing that the "drab" peahen's coloration is itself adaptive, as camouflage. Wallace more speculatively argued that the bright colors and long tails of the peacock were not adaptive in any way, and that bright coloration could result from non-adaptive physiological development (for example, the internal organs of animals, not being subject to a visual form of natural selection, come in a wide variety of bright colors). This has been questioned by later scholars as quite a stretch for Wallace, who in this particular instance abandoned his normally strict "adaptationist" agenda in asserting that the highly intricate and developed forms such as a peacock's tail resulted by sheer "physiological processes" that were somehow not at all subjected to adaptation.
Though Darwin considered sexual and natural selection to be two separate processes of equal importance, most of his contemporaries were not convinced, and sexual selection is usually de-emphasized as being a lesser force than, or simply a part of, natural selection.
The sciences of evolutionary psychology, human behavioral ecology, and sociobiology study the influence of sexual selection in humans, though these are often controversial fields.
Read more about this topic: Sexual Selection
Famous quotes containing the words history, application and/or theory:
“To a surprising extent the war-lords in shining armour, the apostles of the martial virtues, tend not to die fighting when the time comes. History is full of ignominious getaways by the great and famous.”
—George Orwell (19031950)
“I think that a young state, like a young virgin, should modestly stay at home, and wait the application of suitors for an alliance with her; and not run about offering her amity to all the world; and hazarding their refusal.... Our virgin is a jolly one; and tho at present not very rich, will in time be a great fortune, and where she has a favorable predisposition, it seems to me well worth cultivating.”
—Benjamin Franklin (17061790)
“... liberal intellectuals ... tend to have a classical theory of politics, in which the state has a monopoly of power; hoping that those in positions of authority may prove to be enlightened men, wielding power justly, they are natural, if cautious, allies of the establishment.”
—Susan Sontag (b. 1933)