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Sexual selection creates colourful differences between sexes in Goldie's bird-of-paradise.Male above; female below. Painting by John Gerrard Keulemans.. Sexual selection is a mechanism of evolution in which members of one biological sex choose mates of the other sex to mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex ...
However, penis size may have been subject to natural selection, rather than sexual selection, due to a larger penis' efficiency in displacing the sperm of rival males during sexual intercourse. A model study showed displacement of semen was directly proportional to the depth of pelvic thrusting, as an efficient semen displacement device. [28]
Mate choice is a major component of sexual selection, another being intrasexual selection. Ideas on sexual selection were first introduced in 1871, by Charles Darwin, then expanded on by Ronald Fisher in 1915. At present, there are five sub mechanisms that explain how mate choice has evolved over time.
In certain cases these differences are as dramatic as genes not being expressed at all in either of the sexes. These differences in gene expression are the result of either natural selection on reproductive potential and survival traits of either sex or sexual selection on traits relevant to intra-sexual competition and inter-sexual mate choice ...
There are two modes of sexual selection: intersexual selection and intrasexual selection. Intersexual selection includes the display of desirable sexual characteristics to attract a potential mate. Intrasexual selection is competition between members of the same sex other over a potential mate.
Many types of avian sexual selection have been identified; intersexual selection, also known as female choice; and intrasexual competition, where individuals of the more abundant sex compete with each other for the privilege to mate. Sexually selected traits often evolve to become more pronounced in competitive breeding situations until the ...
Elephants can use their ears as threat displays in male-to-male competition. Sexual selection in mammals is a process the study of which started with Charles Darwin's observations concerning sexual selection, including sexual selection in humans, and in other mammals, [1] consisting of male–male competition and mate choice that mold the development of future phenotypes in a population for a ...
In ethology, male-male intrasexual competition occurs when two males of the same species compete for the opportunity to mate with a female. Sexually dimorphic traits, size, sex ratio, [1] and the social situation [2] may all play a role in the effects male-male competition has on the reproductive success of a male and the mate choice of a female.