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Sexual Selection
Sexual selection is a mechanism of evolution in which members of one sex mate choice, choose mates of the other sex to mating, mate with (intersexual selection), and compete with members of the same sex for access to members of the opposite sex (intrasexual selection). These two forms of selection mean that some individuals have greater reproductive success than others within a population, for example because they are more Animal sexual behaviour, attractive or prefer more attractive partners to produce offspring. Successful males benefit from frequent mating and monopolizing access to one or more fertile females. Females can maximise the return on the energy they invest in reproduction by selecting and mating with the best males. The concept was first articulated by Charles Darwin who wrote of a "second agency" other than natural selection, in which competition between mate candidates could lead to speciation. The theory was given a mathematical basis by Ronald Fisher in the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deer
A deer (: deer) or true deer is a hoofed ruminant ungulate of the family Cervidae (informally the deer family). Cervidae is divided into subfamilies Cervinae (which includes, among others, muntjac, elk (wapiti), red deer, and fallow deer) and Capreolinae (which includes, among others reindeer (caribou), white-tailed deer, roe deer, and moose). Male deer of almost all species (except the water deer), as well as female reindeer, grow and shed new antlers each year. These antlers are bony extensions of the skull and are often used for combat between males. The musk deer ( Moschidae) of Asia and chevrotains ( Tragulidae) of tropical African and Asian forests are separate families that are also in the ruminant clade Ruminantia; they are not especially closely related to Cervidae. Deer appear in art from Paleolithic cave paintings onwards, and they have played a role in mythology, religion, and literature throughout history, as well as in heraldry, such as red deer that app ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Russel Wallace
Alfred Russel Wallace (8 January 1823 – 7 November 1913) was an English naturalist, explorer, geographer, anthropologist, biologist and illustrator. He independently conceived the theory of evolution through natural selection; his 1858 paper on the subject was published that year On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection, alongside extracts from Charles Darwin's earlier writings on the topic. It spurred Darwin to set aside the Natural Selection (manuscript), "big species book" he was drafting and to quickly write an Abstract (summary), abstract of it, which was published in 1859 as ''On the Origin of Species''. Wallace did extensive fieldwork, starting in the Amazon River basin. He then did fieldwork in the Malay Archipelago, where he identified the faunal divide now termed the Wallace Line, which separates the Indonesian archipelago into two distinct parts: a western portion in which the ani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trends In Ecology & Evolution
A fad, trend, or craze is any form of collective behavior that develops within a culture, a generation, or social group in which a group of people enthusiastically follow an impulse for a short time period. Fads are objects or behaviors that achieve short-lived popularity but fade away. Fads are often seen as sudden, quick-spreading, and short-lived events. Fads include diets, clothing, hairstyles, toys, and more. Some popular fads throughout history are toys such as yo-yos, hula hoops, and fad dances such as the Macarena, floss and the twist. Similar to habits or customs but less durable, fads often result from an activity or behavior being perceived as popular or exciting within a peer group, or being deemed " cool" as often promoted by social networks.Kornblum (2007), p. 213. A fad is said to "catch on" when the number of people adopting it begins to increase to the point of being noteworthy or going viral. Fads often fade quickly when the perception of novelty i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peahen
Peafowl is a common name for two bird species of the genus '' Pavo'' and one species of the closely related genus ''Afropavo'' within the tribe Pavonini of the family Phasianidae (the pheasants and their allies). Male peafowl are referred to as peacocks, and female peafowl are referred to as peahens. The two Asiatic species are the blue or Indian peafowl originally from the Indian subcontinent, and the green peafowl from Southeast Asia. The third peafowl species, the Congo peafowl, is native only to the Congo Basin. Male peafowl are known for their piercing calls and their extravagant plumage. The latter is especially prominent in the Asiatic species, which have an eye-spotted "tail" or "train" of covert feathers, which they display as part of a courtship ritual. The functions of the elaborate iridescent coloration and large "train" of peacocks have been the subject of extensive scientific debate. Charles Darwin suggested that they served to attract females, and the showy f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Descent Of Man, And Selection In Relation To Sex
''The Descent of Man, and Selection in Relation to Sex'' is a book by English naturalist Charles Darwin, first published in 1871, which applies evolutionary theory to human evolution, and details his theory of sexual selection, a form of biological adaptation distinct from, yet interconnected with, natural selection. Darwin used the word "descent" to mean lineal descendant of ancestors. The book discusses many related issues, including evolutionary psychology, evolutionary ethics, evolutionary musicology, differences between human races, differences between sexes, the dominant role of women in mate choice, and the relevance of the evolutionary theory to society. Publication As Darwin wrote, he sent chapters to his daughter Henrietta for editing to ensure that damaging inferences could not be drawn, and also took advice from his wife Emma. The zoological illustrator T. W. Wood, (who had also illustrated Wallace's '' The Malay Archipelago'' (1869)), drew many of the figure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
On The Origin Of Species
''On the Origin of Species'' (or, more completely, ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life'')The book's full original title was ''On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life''. In the 1872 sixth edition, "On" was omitted, so the full title is ''The origin of species by means of natural selection, or the preservation of favoured races in the struggle for life.'' This edition is usually known as ''The Origin of Species.'' The 6th is Darwin's final edition; there were minor modifications in the text of certain subsequent issues. See Freeman, R. B. In Van Wyhe, John, ed. ''Darwin Online: On the Origin of Species'', 2002. is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. It was published on 24 November 1859. Darwin's book introduced the scientific theory that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin Sexual Caricature
Darwin may refer to: Common meanings * Charles Darwin (1809–1882), English naturalist and writer, best known as the originator of the theory of biological evolution by natural selection * Darwin, Northern Territory, a capital city in Australia, named after the naturalist Arts and entertainment * ''Darwin'' (1920 film), a German silent film * ''Darwin'' (2011 film), a documentary * ''Darwin'' (2015 film), a science fiction film by Alain Desrochers * Darwin (''seaQuest DSV''), a dolphin in the TV series ''seaQuest DSV'' * '' Darwin!'', a 1972 album by Banco del Mutuo Soccorso * '' Darwin: The Life of a Tormented Evolutionist'', a 1991 biography of Charles Darwin * Darwin (Marvel Comics), a Marvel Comics fictional superhero associated with the X-Men * Darwin Watterson, a character from the 2011 animated TV series ''The Amazing World of Gumball'' Computing * Darwin (ADL), an architecture description language * Darwin (operating system), the Unix base for Apple's iOS and macOS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Selection In Fungi
Sexual selection has been observed in fungi as a part of their reproduction, although they also often reproduce asexually. In the basidiomycetes, the sex ratio is biased towards males, implying sexual selection there. Male–male competition to fertilize occurs in fungi including yeasts. Pheromone signaling is used by female gametes and by conidia, implying male choice in these cases. Female–female competition may also occur, indicated by the much faster evolution of female-biased genes in fungi. Fungal sexual selection requirements Most fungi can produce asexually and sexually. Currently, sexual selection has been studied to occur more predominantly in the Ascomycota and Basidiomycota phyla. Although different sexes are not present within fungi, sexual selection can act due to the presence of different sex roles as well as different mating types as most fungi are hermaphroditic.Nieuwenhuis, B. P. S. and Aanen, D. K. (2012), Sexual selection in fungi. J. Evol. Biol., 25: 2397 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Selection In Flowering Plants
Sexual selection is natural selection arising through preference by one sex for certain characteristics in individuals of the other sex. It is a common concept in animal evolution but, with plants, it is often overlooked because many plants are hermaphrodites. Flowering plants have many sexually selected characteristics. For example, flower symmetry, nectar production, floral structure, and inflorescences are among the secondary sex characteristics acted upon by sexual selection. Sexual dimorphisms and reproductive organs can also be affected by sexual selection. Mechanisms of sexual selection There are two main mechanisms of sexual selection in flowering plants, one being intra-sexual competition and the other being female mate choice. Intrasexual selection, Intra-sexual selection is responsible for much of floral evolution and diversification. Intrasexual selection, with the help of pollinators, has also led to some of the most remarkable examples of exaggerated traits among Herm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sex Ratio
A sex ratio is the ratio of males to females in a population. As explained by Fisher's principle, for evolutionary reasons this is typically about 1:1 in species which reproduce sexually. However, many species deviate from an even sex ratio, either periodically or permanently. These include parthenogenic and androgenetic species, periodically mating organisms such as aphids, some eusocial wasps, bees, ants, and termites. Types In most species, the sex ratio varies according to the age profile of the population. It is generally divided into four subdivisions: * — ratio at fertilization * — ratio at birth * — ratio in sexually mature organisms ** The tertiary sex ratio is equivalent to the (ASR), which is defined as the ratio of adult males to females in a population. ** The operational sex ratio (OSR) is the ratio of ''sexually active'' males to females in a population, and is therefore derived from a subset of the individuals included when calculating the ASR. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisher's Principle
Fisher's principle is an evolutionary model that explains why the sex ratio of most species that produce offspring through sexual reproduction is approximately 1:1 between males and females. A. W. F. Edwards has remarked that it is "probably the most celebrated argument in evolutionary biology". Fisher's principle was outlined by Ronald Fisher in his 1930 book ''The Genetical Theory of Natural Selection'' (but has been incorrectly attributed as original to Fisher). Fisher couched his argument in terms of parental expenditure, and predicted that parental expenditure on both sexes should be equal. Sex ratios that are 1:1 are hence known as "", and those that are ''not'' 1:1 are "" or "" and occur because they break the assumptions made in Fisher's model. Basic explanation W. D. Hamilton gave the following simple explanation in his 1967 paper on "Extraordinary sex ratios", given the condition that males and females cost equal amounts to produce: # Suppose male births are less commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
