90-418: Men is the plural of man, an adult male human being. Men or MEN may also refer to: Men A man is an adult male human . Before adulthood, a male human is referred to as a boy (a male child or adolescent ). Like most other male mammals , a man's genome usually inherits an X chromosome from the mother and a Y chromosome from the father. Sex differentiation of
180-752: A gender binary in which man is one of the two genders, the other being woman . Most men are cisgender , and their gender identity aligns with their male sex assignment at birth. Trans men have a male gender identity that does not align with their female sex assignment at birth, and may undergo masculinizing hormone replacement therapy and/or sex reassignment surgery . Intersex men may have sex characteristics that do not fit typical notions of male biology. A 2016 systemic review estimated that 0.256% of people self-identify as female-to-male transgender. A 2017 survey of 80,929 Minnesota students found that roughly twice as many female-assigned adolescents self-identified as transgender, compared to adolescents with
270-639: A gender identity that does not align with their female sex assignment at birth, while intersex men may have sex characteristics that do not fit typical notions of male biology. The English term "man" is derived from the Proto-Indo-European root *man- (see Sanskrit / Avestan manu- , Slavic mǫž "man, male"). More directly, the word derives from Old English mann . The Old English form primarily meant "person" or "human being" and referred to men, women, and children alike. The Old English word for "man" as distinct from " woman " or "child"
360-501: A bird's lifetime. Activational hormones occur during puberty and adulthood and serve to 'activate' certain behaviors when appropriate, such as territoriality during breeding season. Organizational hormones occur only during a critical period early in development, either just before or just after hatching in most birds, and determine patterns of behavior for the rest of the bird's life. Such behavioral differences can cause disproportionate sensitivities to anthropogenic pressures. Females of
450-459: A diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection . The opposite of dimorphism
540-553: A large role in the changing of sex by the fish. It is often seen that a fish will change its sex when there is a lack of a dominant male within the social hierarchy. The females that change sex are often those who attain and preserve an initial size advantage early in life. In either case, females which change sex to males are larger and often prove to be a good example of dimorphism. In other cases with fish, males will go through noticeable changes in body size, and females will go through morphological changes that can only be seen inside of
630-1011: A less bright or less exaggerated color during the off-breeding season. This occurs because the species is more focused on survival than on reproduction, causing a shift into a less ornate state. Consequently, sexual dimorphism has important ramifications for conservation. However, sexual dimorphism is not only found in birds and is thus important to the conservation of many animals. Such differences in form and behavior can lead to sexual segregation , defined as sex differences in space and resource use. Most sexual segregation research has been done on ungulates, but such research extends to bats , kangaroos , and birds. Sex-specific conservation plans have even been suggested for species with pronounced sexual segregation. The term sesquimorphism (the Latin numeral prefix sesqui - means one-and-one-half, so halfway between mono - (one) and di - (two)) has been proposed for bird species in which "both sexes have basically
720-491: A majority of on the job deaths. Further, medical doctors provide men with less service, less advice, and spend less time with men than they do with women per medical encounter. Male sexuality and attraction varies between individuals, and a man's sexual behavior can be affected by many factors, including evolved predispositions , personality , upbringing , and culture . While most men are heterosexual , significant minorities are homosexual or bisexual . Most cultures use
810-414: A male karyotype (XY). The SRY gene is typically found on the Y chromosome and causes the development of the testes, which in turn govern other aspects of male sex differentiation . Sex differentiation in males proceeds in a testes-dependent way while female differentiation is not gonad dependent. Primary sex characteristics (or sex organs) are characteristics that are present at birth and are integral to
900-400: A male sex assignment. Masculinity (also sometimes called manhood or manliness ) is the set of personality traits and attributes associated with boys and men. Although masculinity is socially constructed , some research indicates that some behaviors considered masculine are biologically influenced. To what extent masculinity is biologically or socially influenced is subject to debate. It
990-441: A man's wardrobe include shirts, trousers, suits, and jackets, which are designed to provide both comfort and style while prioritizing functionality. Men's fashion also encompasses more casual garments such as t-shirts , sweatshirts , jeans , shorts , and swimwear , which are typically intended for informal settings. Cultural and regional traditions often influence men's fashion, resulting in diverse styles and garments that reflect
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#17327804763581080-425: A naturally occurring part of development, for example plumage. In addition, the strong hormonal influence on phenotypic differences suggests that the genetic mechanism and genetic basis of these sexually dimorphic traits may involve transcription factors or cofactors rather than regulatory sequences. Sexual dimorphism may also influence differences in parental investment during times of food scarcity. For example, in
1170-725: A proactive role, initiate the relationship, plan dates, and propose marriage. Anthropology has shown that masculinity itself has social status , just like wealth, race and social class. In Western culture , for example, greater masculinity usually brings greater social status. Many English words such as virtue and virile (from the Indo-European root vir meaning man ) reflect this. In most cultures, male privilege allows men more rights and privileges than women. In societies where men are not given special legal privileges, they typically hold more positions of power, and men are seen as being taken more seriously in society. This
1260-414: A significant role in male reproductive success. Males have a propensity to be larger than females of a comparable age but it is unclear whether the size increase is due to a growth spurt at the time of the sexual transition or due to the history of faster growth in sex changing individuals. Larger males are able to stifle the growth of females and control environmental resources. Social organization plays
1350-542: A speciation phenomenon if the variation becomes strongly drastic and favorable towards two different outcomes. Sexual dimorphism is maintained by the counteracting pressures of natural selection and sexual selection. For example, sexual dimorphism in coloration increases the vulnerability of bird species to predation by European sparrowhawks in Denmark. Presumably, increased sexual dimorphism means males are brighter and more conspicuous, leading to increased predation. Moreover,
1440-480: A woman. Since sperm that enters a woman's uterus and then fallopian tubes goes on to fertilize an egg which develops into a fetus or child, the male reproductive system plays no necessary role during the gestation . The study of male reproduction and associated organs is called andrology . Testosterone stimulates the development of the Wolffian ducts , the penis, and closure of the labioscrotal folds into
1530-474: Is Lamprologus callipterus , a type of cichlid fish. In this fish, the males are characterized as being up to 60 times larger than the females. The male's increased size is believed to be advantageous because males collect and defend empty snail shells in each of which a female breeds. Males must be larger and more powerful in order to collect the largest shells. The female's body size must remain small because in order for her to breed, she must lay her eggs inside
1620-543: Is Lasioglossum hemichalceum , which is a species of sweat bee that shows drastic physical dimorphisms between male offspring. Not all dimorphism has to have a drastic difference between the sexes. Andrena agilissima is a mining bee where the females only have a slightly larger head than the males. Weaponry leads to increased fitness by increasing success in male–male competition in many insect species. The beetle horns in Onthophagus taurus are enlarged growths of
1710-516: Is armed conflicts , where men are often the immediate victims. A study of conflicts in 13 countries from 1955 to 2002 found that 81% of all violent war deaths were male. Apart from armed conflicts, areas with high incidence of violence, such as regions controlled by drug cartels , also see men experiencing higher mortality rates. This stems from social beliefs that associate ideals of masculinity with aggressive, confrontational behavior. Lastly, sudden and drastic changes in economic environments and
1800-541: Is distinct from the definition of the biological male sex , as both males and females can exhibit masculine traits. Men generally face social stigma for embodying feminine traits, more so than women do for embodying masculine traits. This can also manifest as homophobia . Standards of manliness or masculinity vary across different cultures and historical periods. While the outward signs of masculinity look different in different cultures, there are some common aspects to its definition across cultures. In all cultures in
1890-627: Is monomorphism , when both biological sexes are phenotypically indistinguishable from each other. Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in the coloration of sexes within a given species is called sexual dichromatism, commonly seen in many species of birds and reptiles. Sexual selection leads to exaggerated dimorphic traits that are used predominantly in competition over mates. The increased fitness resulting from ornamentation offsets its cost to produce or maintain, suggesting complex evolutionary implications, but
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#17327804763581980-770: Is "fanciful" and all the historical evidence favours "the conclusion of the French classical scholar Claude de Saumaise " that it is derived from θρ , the contraction of a Greek epithet for Mars, θοῦρος ( Thouros ). Sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different morphological characteristics, including characteristics not directly involved in reproduction . The condition occurs in most dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics , size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved
2070-423: Is a good indicator for females because it shows that they are good at obtaining a food supply from which the carotenoid is obtained. There is a positive correlation between the chromas of the tail and breast feathers and body condition. Carotenoids play an important role in immune function for many animals, so carotenoid dependent signals might indicate health. Frogs constitute another conspicuous illustration of
2160-407: Is a sexually dimorphic trait. Theropoda It has been hypothesized that male theropods possessed a retractable penis, a feature similar to modern day crocodilians . Crocodilian skeletons were examined to determine whether there is a skeletal component that is distinctive between both sexes, to help provide an insight on the physical disparities between male and female theropods. Findings revealed
2250-423: Is advantageous to both parties because it avoids damaging the developing fruit and wasting the pollinator's effort on unrewarding visits. In effect, the strategy ensures that pollinators can expect a reward every time they visit an appropriately advertising flower. Females of the aquatic plant Vallisneria americana have floating flowers attached by a long flower stalk that are fertilized if they contact one of
2340-587: Is also displayed by dichromatism. In butterfly genera Bicyclus and Junonia , dimorphic wing patterns evolved due to sex-limited expression, which mediates the intralocus sexual conflict and leads to increased fitness in males. The sexual dichromatic nature of Bicyclus anynana is reflected by female selection on the basis of dorsal UV-reflective eyespot pupils. The common brimstone also displays sexual dichromatism; males have yellow and iridescent wings, while female wings are white and non-iridescent. Naturally selected deviation in protective female coloration
2430-673: Is also seen in frog species like P. bibroni i . Male painted dragon lizards, Ctenophorus pictus . are brightly conspicuous in their breeding coloration, but male colour declines with aging . Male coloration appears to reflect innate anti-oxidation capacity that protects against oxidative DNA damage . Male breeding coloration is likely an indicator to females of the underlying level of oxidative DNA damage (a significant component of aging) in potential mates. Possible mechanisms have been proposed to explain macroevolution of sexual size dimorphism in birds. These include sexual selection, selection for fecundity in females, niche divergence between
2520-642: Is associated with a "gender-role strain" in which men face increased societal pressure to conform to gender roles. The earliest known recorded name of a man in writing is potentially Kushim , who would have lived sometime between 3400 and 3000 BC in the Sumerian city of Uruk ; though his name may have been a title rather than his actual name. The earliest confirmed names are that of Gal-Sal and his two slaves named En-pap X and Sukkalgir, from c. 3100 BC . Men may have children, whether biological or adopted ; such men are called fathers. The role of men in
2610-470: Is believed that this is obtained by the ingestion of green Lepidopteran larvae, which contain large amounts of the carotenoids lutein and zeaxanthin . This diet also affects the sexually dimorphic colours in the human-invisible ultraviolet spectrum. Hence, the male birds, although appearing yellow to humans, actually have a violet-tinted plumage that is seen by females. This plumage is thought to be an indicator of male parental abilities. Perhaps this
2700-410: Is displayed in mimetic butterflies. Many arachnid groups exhibit sexual dimorphism, but it is most widely studied in the spiders. In the orb-weaving spider Zygiella x-notata , for example, adult females have a larger body size than adult males. Size dimorphism shows a correlation with sexual cannibalism , which is prominent in spiders (it is also found in insects such as praying mantises ). In
2790-687: Is known in ceratopsids, although there is evidence that the more primitive ceratopsian Protoceratops andrewsi possessed sexes that were distinguishable based on frill and nasal prominence size. This is consistent with other known tetrapod groups where midsized animals tend to exhibit markedly more sexual dimorphism than larger ones. However, it has been proposed that these differences can be better explained by intraspecific and ontogenic variation rather than sexual dimorphism. In addition, many sexually dimorphic traits that may have existed in ceratopsians include soft tissue variations such as coloration or dewlaps , which would be unlikely to have been preserved in
Men (disambiguation) - Misplaced Pages Continue
2880-678: Is more prominently selected for in less dimorphic species of spiders, which often selects for larger male size. In the species Maratus volans , the males are known for their characteristic colorful fan which attracts the females during mating. Ray-finned fish are an ancient and diverse class, with the widest degree of sexual dimorphism of any animal class. Fairbairn notes that "females are generally larger than males but males are often larger in species with male–male combat or male paternal care ... [sizes range] from dwarf males to males more than 12 times heavier than females." There are cases where males are substantially larger than females. An example
2970-402: Is of a subdued brown coloration. The plumage of the peacock increases its vulnerability to predators because it is a hindrance in flight, and it renders the bird conspicuous in general. Similar examples are manifold, such as in birds of paradise and argus pheasants . Another example of sexual dichromatism is that of nestling blue tits . Males are chromatically more yellow than females. It
3060-778: Is overwhelmingly discriminatory , currently only ten countries include women in their conscription programs. Men continue to hold more dangerous jobs than women, even in developed countries. In the United States in 2020, ten times as many men died on the job as women, and a man was ten times more likely to die on the job than a woman. Media portrayals of men often replicate traditional understanding of masculinity. Men are portrayed more frequently in television than women and most commonly appear as leads in action and drama programming. Men are typically more active in television programming than women and typically hold more power and status. Due to their prominence, men are more likely to be both
3150-434: Is seen in the bee species Macrotera portalis in which there is a small-headed morph, capable of flight, and large-headed morph, incapable of flight, for males. Anthidium manicatum also displays male-biased sexual dimorphism. The selection for larger size in males rather than females in this species may have resulted due to their aggressive territorial behavior and subsequent differential mating success. Another example
3240-480: Is selected for, which is seen in the family Araneidae . All Argiope species, including Argiope bruennichi , use this method. Some males evolved ornamentation including binding the female with silk, having proportionally longer legs, modifying the female's web, mating while the female is feeding, or providing a nuptial gift in response to sexual cannibalism. Male body size is not under selection due to cannibalism in all spider species such as Nephila pilipes , but
3330-523: Is stigmatized. Domestic violence against men is similarly stigmatized, although men make up half of the victims in heterosexual couples. Opponents of circumcision describe it as a human rights violation. The fathers' rights movement seeks to support separated fathers that do not receive equal rights to care for their children. The men's movement is the response to issues faced by men in Western countries. It includes pro-feminist groups such as
3420-407: Is strong when the factor of environmental selection is also introduced. Environmental selection may support a smaller chick size if those chicks were born in an area that allowed them to grow to a larger size, even though under normal conditions they would not be able to reach this optimal size for migration. When the environment gives advantages and disadvantages of this sort, the strength of selection
3510-504: Is the dragonet , in which males are considerably larger than females and possess longer fins. Sexual dimorphism also occurs in hermaphroditic fish. These species are known as sequential hermaphrodites . In fish, reproductive histories often include the sex-change from female to male where there is a strong connection between growth, the sex of an individual, and the mating system within which it operates. In protogynous mating systems where males dominate mating with many females, size plays
3600-411: Is weakened and the environmental forces are given greater morphological weight. The sexual dimorphism could also produce a change in timing of migration leading to differences in mating success within the bird population. When the dimorphism produces that large of a variation between the sexes and between the members of the sexes, multiple evolutionary effects can take place. This timing could even lead to
3690-604: The blue-footed booby , the female chicks grow faster than the males, resulting in booby parents producing the smaller sex, the males, during times of food shortage. This then results in the maximization of parental lifetime reproductive success. In Black-tailed Godwits Limosa limosa limosa females are also the larger sex, and the growth rates of female chicks are more susceptible to limited environmental conditions. Sexual dimorphism may also only appear during mating season; some species of birds only show dimorphic traits in seasonal variation. The males of these species will molt into
Men (disambiguation) - Misplaced Pages Continue
3780-646: The male reproductive system , which includes the testicles , sperm ducts , prostate gland and epididymides , and penis . Secondary sex characteristics include a narrower pelvis and hips , and smaller breasts and nipples . Throughout human history , traditional gender roles have often defined men's activities and opportunities. Men often face conscription into military service or are directed into professions with high mortality rates . Many religious doctrines stipulate certain rules for men, such as religious circumcision . Men are over-represented as both perpetrators and victims of violence . Trans men have
3870-487: The men's liberation movement , and anti-feminist groups such as the manosphere . The Mars symbol (♂) is a common symbol that represents the male sex. The symbol is identical to the planetary symbol of Mars . It was first used to denote sex by Carl Linnaeus in 1751. The symbol is sometimes seen as a stylized representation of the shield and spear of the Roman god Mars . According to Stearn, however, this derivation
3960-489: The ovules ). Each pollen grain accordingly may be seen as a male plant in its own right; it produces a sperm cell and is dramatically different from the female plant, the megagametophyte that produces the female gamete. Insects display a wide variety of sexual dimorphism between taxa including size, ornamentation and coloration. The female-biased sexual size dimorphism observed in many taxa evolved despite intense male-male competition for mates. In Osmia rufa , for example,
4050-438: The sexually dimorphic phenotypic traits that distinguish between the sexes, but—unlike the primary sex characteristics—are not directly part of the reproductive system . Secondary sexual characteristics that are specific to men include: Men weigh more than women. On average, men are taller than women by about 10%. On average, men have a larger waist in comparison to their hips (see waist–hip ratio ) than women. In women,
4140-410: The vasa deferentia and ejaculatory ducts , tubular structures that transfer the mature sperm to the urethra. The external male genitalia consist of the penis , an organ that expels semen , and the scrotum , a pouch of skin housing the testicles. The male reproductive system's function is to produce semen , which carries sperm and thus genetic information that can unite with an egg within
4230-552: The "head of household" and held additional social privileges. Men have traditionally held jobs that were not available to women. Such jobs tended to be either more strenuous, more prestigious, or more dangerous. Modern men increasingly take untraditional career paths, such as staying home and raising children while their partner works. Modern men tend to work longer than women, which impacts their ability to spend time with their families. Even in modern times, some jobs remain available only to men, such as military service. Conscription
4320-407: The 'fittest' available male. Sexual dimorphism is a product of both genetics and environmental factors. An example of sexual polymorphism determined by environmental conditions exists in the red-backed fairywren . Red-backed fairywren males can be classified into three categories during breeding season : black breeders, brown breeders, and brown auxiliaries. These differences arise in response to
4410-533: The bird's body condition: if they are healthy they will produce more androgens thus becoming black breeders, while less healthy birds produce less androgens and become brown auxiliaries. The reproductive success of the male is thus determined by his success during each year's non-breeding season, causing reproductive success to vary with each year's environmental conditions. Migratory patterns and behaviors also influence sexual dimorphisms. This aspect also stems back to size dimorphism in species. It has been shown that
4500-1001: The body. For example, in sockeye salmon , males develop larger body size at maturity, including an increase in body depth, hump height, and snout length. Females experience minor changes in snout length, but the most noticeable difference is the huge increase in gonad size, which accounts for about 25% of body mass. Sexual selection was observed for female ornamentation in Gobiusculus flavescens , known as two-spotted gobies. Traditional hypotheses suggest that male–male competition drives selection. However, selection for ornamentation within this species suggests that showy female traits can be selected through either female–female competition or male mate choice. Since carotenoid-based ornamentation suggests mate quality, female two-spotted guppies that develop colorful orange bellies during breeding season are considered favorable to males. The males invest heavily in offspring during incubation, which leads to
4590-470: The caudal chevrons of male crocodiles, used to anchor the penis muscles, were significantly larger than those of females. There have been criticisms of these findings, but it remains a subject of debate among advocates and adversaries. Ornithopoda Studies of sexual dimorphism in hadrosaurs have generally centered on the distinctive cranial crests , which likely provided a function in sexual display. A biometric study of 36 skulls found sexual dimorphism
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#17327804763584680-432: The common cold found that doctors underrate the symptoms of men, and are more willing to attribute symptoms and illness to women than men. Women live longer than men in all countries, and across all age groups, for which reliable records exist. In the United States, men are less healthy than women across all social classes. Non-white men are especially unhealthy. Men are over-represented in dangerous occupations and represent
4770-400: The costs and evolutionary implications vary from species to species. The peafowl constitute conspicuous illustrations of the principle. The ornate plumage of peacocks, as used in the courting display, attracts peahens . At first sight, one might mistake peacocks and peahens for completely different species because of the vibrant colours and the sheer size of the male's plumage; the peahen
4860-654: The degree of preservation. The availability of well-preserved remains is not a probable outcome as a consequence of decomposition and fossilization . Some paleontologists have looked for sexual dimorphism among dinosaurs using statistics and comparison to ecologically or phylogenetically related modern animals. Apatosaurus and Diplodocus Female Apatosaurus and Diplodocus had interconnected caudal vertebrae that allowed them to keep their tails elevated to aid in copulation. Discovering that this fusion occurred in only 50% of Apatosaurus and Diplodocus skeletons and 25% of Camarasaurus skeletons indicated that this
4950-448: The empty shells. If she grows too large, she will not fit in the shells and will be unable to breed. The female's small body size is also likely beneficial to her chances of finding an unoccupied shell. Larger shells, although preferred by females, are often limited in availability. Hence, the female is limited to the growth of the size of the shell and may actually change her growth rate according to shell size availability. In other words,
5040-516: The estrogen pathway. The sexual dimorphism in lizards is generally attributed to the effects of sexual selection, but other mechanisms including ecological divergence and fecundity selection provide alternative explanations. The development of color dimorphism in lizards is induced by hormonal changes at the onset of sexual maturity, as seen in Psamodromus algirus , Sceloporus gadoviae , and S. undulates erythrocheilus . Sexual dimorphism in size
5130-443: The exhausted anthers after a day or two and perhaps change their colours as well while the pistil matures; specialist pollinators are very much inclined to concentrate on the exact appearance of the flowers they serve, which saves their time and effort and serves the interests of the plant accordingly. Some such plants go even further and change their appearance once fertilized, thereby discouraging further visits from pollinators. This
5220-555: The family has shifted considerably in the 20th and 21st centuries, taking on a more active role in raising children in most societies. Men would traditionally marry a woman when raising children, but in modern times many countries now allow for same-sex marriage , and for those couples to raise children either via adoption or surrogacy . Men may be single parents , and are increasingly so in modern times, though women are three times more likely to be single parents than men. In paternal societies, men have typically have been regarded as
5310-417: The female is larger/broader than males, with males being 8–10 mm in size and females being 10–12 mm in size. In the hackberry emperor females are similarly larger than males. The reason for the sexual dimorphism is due to provision size mass, in which females consume more pollen than males. In some species, there is evidence of male dimorphism, but it appears to be for distinctions of roles. This
5400-564: The female, which looks different from the males. Various other dioecious exceptions, such as Loxostylis alata have visibly different sexes, with the effect of eliciting the most efficient behavior from pollinators, who then use the most efficient strategy in visiting each gender of flower instead of searching, say, for pollen in a nectar-bearing female flower. Some plants, such as some species of Geranium have what amounts to serial sexual dimorphism. The flowers of such species might, for example, present their anthers on opening, then shed
5490-651: The form of reduced survival. This means that even if the trait causes males to die earlier, the trait is still beneficial so long as males with the trait produce more offspring than males lacking the trait. This balance keeps dimorphism alive in these species and ensures that the next generation of successful males will also display these traits that are attractive to females. Such differences in form and reproductive roles often cause differences in behavior. As previously stated, males and females often have different roles in reproduction. The courtship and mating behavior of males and females are regulated largely by hormones throughout
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#17327804763585580-734: The fossil record. Stegosaurians A 2015 study on specimens of Hesperosaurus mjosi found evidence of sexual dimorphism in the shape of the dermal plates. Two plate morphs were described: one was short, wide, and oval-shaped, the other taller and narrower. In a large proportion of mammal species, males are larger than females. Both genes and hormones affect the formation of many animal brains before " birth " (or hatching ), and also behaviour of adult individuals. Hormones significantly affect human brain formation, and also brain development at puberty. A 2004 review in Nature Reviews Neuroscience observed that "because it
5670-705: The head or thorax expressed only in the males. Copris ochus also has distinct sexual and male dimorphism in head horns. Another beetle with a distinct horn-related sexual dimorphism is Allomyrina dichotoma, also known as the Japanese rhinoceros beetle . These structures are impressive because of the exaggerated sizes. There is a direct correlation between male horn lengths and body size and higher access to mates and fitness. In other beetle species, both males and females may have ornamentation such as horns. Generally, insect sexual size dimorphism (SSD) within species increases with body size. Sexual dimorphism within insects
5760-451: The index and ring fingers tend to be either more similar in size or their index finger is slightly longer than their ring finger, whereas men's ring finger tends to be longer. The internal male genitalia consist of the testicles , gonads that produce male gametes called sperm , the prostate , seminal vesicles , and bulbourethral glands , accessory glands that partake in sperm health, the epididymides , organs that store sperm cells, and
5850-444: The larger males are better at coping with the difficulties of migration and thus are more successful in reproducing when reaching the breeding destination. When viewing this from an evolutionary standpoint, many theories and explanations come into consideration. If these are the result for every migration and breeding season, the expected results should be a shift towards a larger male population through sexual selection. Sexual selection
5940-436: The loss of social safety nets , in particular social subsidies and food stamps, have also been linked to higher levels of alcohol consumption and psychological stress among men, leading to a spike in male mortality rates. This is because such situations often makes it harder for men to provide for their family, a task that has been long regarded as the "essence of masculinity." A retrospective analyses of people infected with
6030-464: The male fetus is governed by the SRY gene on the Y chromosome. During puberty, hormones which stimulate androgen production result in the development of secondary sexual characteristics that result in even more differences between the sexes. These include greater muscle mass , greater height, the growth of facial hair and a lower body fat composition. Male anatomy is distinguished from female anatomy by
6120-508: The male's ability to collect large shells depends on his size. The larger the male, the larger the shells he is able to collect. This then allows for females to be larger in his brooding nest which makes the difference between the sizes of the sexes less substantial. Male–male competition in this fish species also selects for large size in males. There is aggressive competition by males over territory and access to larger shells. Large males win fights and steal shells from competitors. Another example
6210-593: The more ornamented or brightly colored sex. Such differences have been attributed to the unequal reproductive contributions of the sexes. This difference produces a stronger female choice since they have more risk in producing offspring. In some species, the male's contribution to reproduction ends at copulation, while in other species the male becomes the main (or only) caregiver. Plumage polymorphisms have evolved to reflect these differences and other measures of reproductive fitness, such as body condition or survival. The male phenotype sends signals to females who then choose
6300-692: The most common causes for mortality in young fish. Most flowering plants are hermaphroditic but approximately 6% of species have separate males and females ( dioecy ). Sexual dimorphism is common in dioecious plants and dioicous species. Males and females in insect-pollinated species generally look similar to one another because plants provide rewards (e.g. nectar ) that encourage pollinators to visit another similar flower , completing pollination . Catasetum orchids are one interesting exception to this rule. Male Catasetum orchids violently attach pollinia to euglossine bee pollinators. The bees will then avoid other male flowers but may visit
6390-407: The objects and instigators of humorous or disparaging content. Fathers are often portrayed in television as either idealized and caring or clumsy and inept. In advertising, men are disproportionately featured in advertisements for alcohol, vehicles, and business products. Men's clothing typically encompasses a range of garments designed for various occasions, seasons, and styles. Fundamental items of
6480-750: The past, and still among traditional and non-Western cultures, getting married is the most common and definitive distinction between boyhood and manhood. In the late 20th century, some qualities traditionally associated with marriage (such as the "triple Ps" of protecting, providing, and procreating ) were still considered signs of having achieved manhood. Platonic relationships are not significantly different between men and women, though some differences do exist. Friendships involving men tend to be based more on shared activities than self-disclosure and personal connection. Perceptions of friendship involving men varies among cultures and time periods. In heterosexual romantic relationships, men are typically expected to take
6570-436: The plants become sexually mature. Every sexually reproducing extant species of the vascular plant has an alternation of generations; the plants we see about us generally are diploid sporophytes , but their offspring are not the seeds that people commonly recognize as the new generation. The seed actually is the offspring of the haploid generation of microgametophytes ( pollen ) and megagametophytes (the embryo sacs in
6660-418: The presence of specific sex-related behaviour is common to many lizards; and vocal qualities which are frequently observed in frogs . Anole lizards show prominent size dimorphism with males typically being significantly larger than females. For instance, the average male Anolis sagrei was 53.4 mm vs. 40 mm in females. Different sizes of the heads in anoles have been explained by differences in
6750-410: The principle. There are two types of dichromatism for frog species: ontogenetic and dynamic. Ontogenetic frogs are more common and have permanent color changes in males or females. Ranoidea lesueuri is an example of a dynamic frog with temporary color changes in males during the breeding season. Hyperolius ocellatus is an ontogenetic frog with dramatic differences in both color and pattern between
6840-408: The production of more exaggerated ornaments in males may come at the cost of suppressed immune function. So long as the reproductive benefits of the trait due to sexual selection are greater than the costs imposed by natural selection, then the trait will propagate throughout the population. Reproductive benefits arise in the form of a larger number of offspring, while natural selection imposes costs in
6930-592: The reproductive process. For men, primary sex characteristics include the penis and testicles . Adult humans exhibit sexual dimorphism in many other characteristics, many of which have no direct link to reproductive ability. Humans are sexually dimorphic in body size, body structure, and body composition. Men tend to be taller and heavier than women, and adjusted for height, men tend to have greater lean and bone mass than women, and lower fat mass. Secondary sex characteristics are features that appear during puberty in humans . Such features are especially evident in
7020-585: The same plumage pattern, though the female is clearly distinguishable by reason of her paler or washed-out colour". Examples include Cape sparrow ( Passer melanurus ), rufous sparrow (subspecies P. motinensis motinensis ), and saxaul sparrow ( P. ammodendri ). Examining fossils of non-avian dinosaurs in search of sexually dimorphic characteristics requires the supply of complete and articulated skeletal and tissue remains. As terrestrial organisms, dinosaur carcasses are subject to ecological and geographical influence that inevitably constitutes
7110-504: The scrotum. Another significant hormone in sexual differentiation is the anti-Müllerian hormone , which inhibits the development of the Müllerian ducts . For males during puberty, testosterone, along with gonadotropins released by the pituitary gland , stimulates spermatogenesis . While a majority of the global health gender disparities is weighted against women, there are situations in which men tend to fare poorer. One such instance
7200-479: The sexes, and allometry, but their relative importance is still not fully understood . Sexual dimorphism in birds can be manifested in size or plumage differences between the sexes. Sexual size dimorphism varies among taxa, with males typically being larger, though this is not always the case, e.g. birds of prey , hummingbirds , and some species of flightless birds. Plumage dimorphism, in the form of ornamentation or coloration, also varies, though males are typically
7290-526: The sexes. At sexual maturity, the males display a bright green with white dorsolateral lines. In contrast, the females are rusty red to silver with small spots. The bright coloration in the male population attracts females and is an aposematic sign to potential predators. Females often show a preference for exaggerated male secondary sexual characteristics in mate selection. The sexy son hypothesis explains that females prefer more elaborate males and select against males that are dull in color, independent of
7380-511: The sexual preference in colorful females due to higher egg quality. In amphibians and reptiles, the degree of sexual dimorphism varies widely among taxonomic groups . The sexual dimorphism in amphibians and reptiles may be reflected in any of the following: anatomy; relative length of tail; relative size of head; overall size as in many species of vipers and lizards ; coloration as in many amphibians , snakes , and lizards, as well as in some turtles ; an ornament as in many newts and lizards;
7470-414: The size dimorphic wolf spider Tigrosa helluo , food-limited females cannibalize more frequently. Therefore, there is a high risk of low fitness for males due to pre-copulatory cannibalism, which led to male selection of larger females for two reasons: higher fecundity and lower rates of cannibalism. In addition, female fecundity is positively correlated with female body size and large female body size
7560-567: The species' vision. Similar sexual dimorphism and mating choice are also observed in many fish species. For example, male guppies have colorful spots and ornamentations, while females are generally grey. Female guppies prefer brightly colored males to duller males. In redlip blennies , only the male fish develops an organ at the anal-urogenital region that produces antimicrobial substances. During parental care, males rub their anal-urogenital regions over their nests' internal surfaces, thereby protecting their eggs from microbial infections, one of
7650-542: The thousands of free-floating flowers released by a male. Sexual dimorphism is most often associated with wind-pollination in plants due to selection for efficient pollen dispersal in males vs pollen capture in females, e.g. Leucadendron rubrum . Sexual dimorphism in plants can also be dependent on reproductive development. This can be seen in Cannabis sativa , a type of hemp, which have higher photosynthesis rates in males while growing but higher rates in females once
7740-531: The unique characteristics of different parts of the world. Men traditionally received more education than women as a result of single-sex education . Universal education, meaning state-provided primary and secondary education independent of gender, is not yet a global norm, even if it is assumed in most developed countries. In the 21st century, the balance has shifted in many developed nations, and men now lag behind women in education. Men are more likely than women to be faculty at universities. In 2020, 90% of
7830-460: The whinchat in Switzerland breed in intensely managed grasslands. Earlier harvesting of the grasses during the breeding season lead to more female deaths. Populations of many birds are often male-skewed and when sexual differences in behavior increase this ratio, populations decline at a more rapid rate. Also not all male dimorphic traits are due to hormones like testosterone, instead they are
7920-472: The world's men were literate , compared to 87% of women. But sub-Saharan Africa, and southwest Asia lagged behind the rest of the world; only 72% of men in sub-Saharan Africa were literate. In most societies, men have more legal and cultural rights than women. and misogyny is far more prevalent than misandry in society. While one in six male experiences sexual assault , men typically receive less support after being victims of it, and rape of males
8010-464: Was wer . Mann only came to mean "man" in Middle English, replacing wer , which survives today only in the compounds " werewolf " (from Old English werwulf , literally "man-wolf"), and " wergild ", literally "man-payment". In humans, sperm cells carry either an X or a Y sex chromosome. If a sperm cell carrying a Y chromosome fertilizes the female ovum , the offspring will have
8100-470: Was exhibited in the crest of 3 species of hadrosaurids. The crests could be categorized as full (male) or narrow (female) and may have given some advantage in intrasexual mating-competition. Ceratopsians According to Scott D. Sampson, if ceratopsids were to exhibit sexual dimorphism, modern ecological analogues suggest it would be found in display structures, such as horns and frills. No convincing evidence for sexual dimorphism in body size or mating signals
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