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Hermaphrodite

Mating Helix aspersa (garden snails).

In biology, a hermaphrodite is a plant or animal that has reproductive organs normally associated with both male and female sexes.[1]

Many taxonomic groups of animals (mostly invertebrates), do not have separate sexes. In these groups, hermaphroditism is a normal condition, enabling a form of sexual reproduction in which both partners can act as the "female" or "male." For example, the great majority of pulmonate snails, opisthobranch snails and slugs are hermaphrodites. Hermaphroditism is also found in some fish and to a lesser degree in other vertebrates. Most plants are also hermaphrodites.

Historically, the term hermaphrodite has also been used to describe ambiguous genitalia and gonadal mosaicism in individuals of gonochoristic species, especially human beings. The word hermaphrodite entered the English lexicon in the 15th century, derived from the Greek Hermaphroditos.[2] Recently, the word "intersex" has come into preferred usage for humans, since the word "hermaphrodite" is considered to be misleading and stigmatizing.[3]


Contents

[edit] Zoology

[edit] Sequential hermaphrodites

Shells of Crepidula fornicata (common slipper shell).

Sequential hermaphrodites (dichogamy) occur in species in which the individual is born as one sex, but can later change into the alternate sex.[4] This is in contrast with simultaneous hermaphrodites, in which an individual may possess fully functional male and female gonads. Sequential hermaphroditism is common in fish (particularly teleost fish), many gastropods (such as the common slipper shell), and some flowering plants. While some sequential hermaphrodites can change sex multiple times, most can only change sex once.[citation needed] Sequential hermaphrodism is important in understanding behavioral ecology and life history theory.

Sequential hermaphrodites fall into two broad categories:

  • Protandry: Where an organism is born as a male, and then changes sex to a female.[4]
    • Example: The clownfish (Genus Amphiprion) are colorful reef fish found living in symbiosis with sea anemones. Generally one anemone contains a 'harem', consisting of a large female, a smaller reproductive male, and even smaller non-reproductive males. If the female is removed, the reproductive male will change sex and the largest of the non-reproductive males will mature and become reproductive. It has been shown that fishing pressure can change when the switch from male to female occurs, since fishermen naturally prefer to catch the larger fish. The populations are generally changing sex at a smaller size, due to natural selection.
  • Protogyny: Where the organism starts as a female, and then changes sex to a male.[4]
    • Example: wrasses (Family Labridae) are a group of reef fish in which protogyny is common. Wrasses also have an uncommon life history strategy, which is termed diandry (literally, two males). In these species, two male morphs exists: an initial phase male or a terminal phase male. Initial phase males do not look like males and spawn in groups with other females. They are not territorial. They are, perhaps, female mimics (which is why they are found swimming in group with other females). Terminal phase males are territorial and have a distinctively bright coloration. Individuals are born as males or females, but if they are born males, they are not born as terminal phase males. Females and initial phase males can become terminal phase males. Usually, the most dominant female or initial phase male replaces any terminal phase male, when those males die or abandon the group.

Dichogamy can have both conservation-related implications for humans, as mentioned above, as well as economic implications. For instance, groupers are favoured fish for eating in many Asian countries and are often aquacultured. Since the adults take several years to change from female to male, the broodstock are extremely valuable individuals.

[edit] Simultaneous hermaphrodites

Earthworms are simultaneous hermaphrodites, having both male and female reproductive organs.

A simultaneous (or synchronous) hermaphrodite (homogamy) is an adult organism that has both male and female sexual organs at the same time.[4] Usually, self-fertilization does not occur.

  • Reproductive system of gastropods: Pulmonate land snails and land slugs are perhaps the best-known kind of simultaneous hermaphrodite, and are the most widespread of terrestrial animals possessing this sexual polymorphism. Sexual material is exchanged between both animals via spermatophore, which can then be stored in the spermatheca. After exchange of spermatozoa, both animals will lay fertilized eggs after a period of gestation; then the eggs will proceed to hatch after a development period. Snails typically reproduce in early spring and late autumn.

Banana slugs are one example of a hermaphroditic gastropod. Mating with a partner is more desirable biologically, as the genetic material of the resultant offspring is varied, but if mating with a partner is not possible, self-fertilization is practised. The male sexual organ of an adult banana slug is quite large in proportion to its size, as well as compared to the female organ. It is possible for banana slugs, while mating, to become stuck together. If a substantial amount of wiggling fails to separate them, the male organ will be bitten off (using the slug's radula), see apophallation. If a banana slug has lost its male sexual organ, it can still mate as a female, making its hermaphroditic quality a valuable adaptation.

  • Hamlets, unlike other fish, seem quite at ease mating in front of divers, allowing observations in the wild to occur readily. They do not practice self-fertilization, but when they find a mate, the pair takes turns between which one acts as the male and which acts as the female through multiple matings, usually over the course of several nights.
  • Earthworms are another example of a simultaneous hermaphrodite. Although they possess ovaries and testes, they have a protective mechanism against self fertilization. Sexual reproduction occurs when two worms meet and exchange gametes, copulating on damp nights during warm seasons. Fertilized eggs are protected by a cocoon, which is buried on or near the surface of the ground.

[edit] Pseudohermaphroditism

Female Hyenas have a clitoris that is greatly enlarged, so much so, that they were described as hermaphrodites – not only by the ancient Greeks, but as recently as the 20th-century circus animal handlers – until scientific information was provided that clarified the misunderstanding.[citation needed]

[edit] Botany

Hylocereus undatus, a hermaphrodite plant with both carpels and stamens

Hermaphrodite is used in botany to describe a flower that has both staminate (male, pollen-producing) and carpellate (female, ovule-producing) parts. This condition is seen in many common garden plants. A closer analogy to hermaphroditism in animals is the presence of separate male and female flowers on the same individual—such plants are called monoecious. Monoecy is especially common in conifers, but occurs in only about 7% of angiosperm species (Molnar, 2004).

[edit] Other uses of the term

Hermaphroditus, mythological character: origin of the word 'Hermaphrodite'.

Hermaphrodite was used to describe any person incompatible with the biological gender binary, but has recently been replaced by intersex in medicine. Humans with typical reproductive organs but atypical clitoris/penis are called pseudohermaphrodites in medical literature.

People with intersex conditions sometimes choose to live exclusively as one sex or the other, using clothing, social cues, genital surgery, and hormone replacement therapy to blend into the sex they identify with more closely. Some people who are intersex, such as some of those with Klinefelter's syndrome and androgen insensitivity syndrome, outwardly appear completely female or male already, without realizing they are intersex. Other kinds of intersex conditions are identified immediately at birth because those with the condition have a sexual organ larger than a clitoris and smaller than a penis. Intersex is thought by some to be caused by unusual sex hormones; the unusual hormones may be caused by an atypical set of sex chromosomes.

Sigmund Freud (based on work by his associate Wilhelm Fliess) held fetal hermaphroditism to be a fact of the physiological development of humans.[citation needed] He based much of his theory of innate sexuality on that assumption.[citation needed] Similarly, in contemporary times, fetuses before sexual differentiation are sometimes described as female by doctors explaining the process.[5] Neither concept is technically true. Before this stage, humans are simply undifferentiated and possess a Müllerian duct, a Wolffian duct, and a genital tubercle.

[edit] Etymology

The term "hermaphrodite" derives from Hermaphroditus, the son of Hermes and Aphrodite in Greek mythology, who was fused with a nymph, Salmacis, resulting in one individual possessing physical traits of both sexes.[6]

[edit] In fiction

  • The Greek mythological figure, Tiresias, appears in classical works, such as Homer's Odyssey, Sophocles' Oedipus the King and in Dante's Renaissance poem, the Divine Comedy. The myth is about how Tiresias is changed from a man to a woman and back by the gods.
  • Julia Ward Howe's unfinished novel The Hermaphrodite, written probably in 1846-1847, features a protagonist, a biological hermaphrodite, who is raised as a man but also spends some time living as a woman. He faces crises of identity and the problems of fitting into European gender roles of the period.
  • Robert A. Heinlein's 1959 short story "—All You Zombies—" is the tale of a (simultaneous yet sequential, by means of surgery to expose hidden male sex organs and remove damaged female organs) hermaphrodite who manages, via time travel, to impregnate his earlier outwardly female self who in turn gives birth to herself.
  • In Harper Lee's To Kill a Mockingbird, Scout famously mishears her neighbor Miss Maudie say the word as 'morphodite,' setting up a comic scene later in the novel when Scout asks Maudie about the meaning of the word.
  • Ursula K. Le Guin's novel, The Left Hand of Darkness, featured a planet inhabited by humans whose ancestors had modified themselves to be sequential hermaphrodites. For twenty-four days of each twenty-six day lunar cycle, they were sexually latent androgynes, and for the remaining two days were male or female, as determined by pheromonal negotiation with an interested sex partner.
  • The 1990 Michael Crichton science fiction novel, Jurassic Park, and its 1993 film adaptation featured dinosaurs exhibiting a sequential hermaphrodite transformation as a key plot point. The ability of the scientists to maintain control over the park's cloned dinosaur population was derived by preventing the dinosaurs from developing a Y chromosome while in fetal development, thus ensuring that they were all females. However, the scientists used DNA of some other animals with sequential hermaphroditic abilities to complete fragmented portions of the dinosaurs' DNA, allowing some of them to become male in adulthood and mate. However, dinosaurs probably had the bird type of sex chromosome system, with ZZ for male and WZ for female, see: ZW sex-determination system.
  • Jeffrey Eugenides's 2002 novel Middlesex is narrated by its protagonist, Calliope Stephanides, who is a male pseudo-hermaphrodite with undescended testicles, a micropenis and hypospadius. Calliope was raised as a girl because her external genitalia resembled those of a female. However, at puberty she did not develop breasts but did develop masculine traits such as facial hair.
  • The 1996 movie Tremors 2: Aftershocks had an animal called a Shrieker, which was determined to be a hermaphrodite after it reproduced without a mate. The animal had a large beak and short tall, stood approximately three feet tall, walked on two legs, and had no arms.
  • The 1993 Gary Jennings novel, Raptor, features Thorn, a hermaphrodite, as its main character.
  • Baron Ashura, one of the Dr. Hell's henchmen in Mazinger Z series, is a hermaphrodite.
  • The Star Trek: New Frontier series features the Hermat species, including Burgoyne 172. Hermats possess both male and female characteristics.
  • In Nabari no Ou, Yoite was a hermaphrodite whose mother died giving birth to him.
  • In Star Wars, Hutts are hermaphrodites.
  • In Episode 17 of Freaks and Geeks, Amy, the girlfriend of Seth Rogen's character Ken, reveals that she was born with both male and female genitalia, but received an operation to become female.
  • In the video game Spore, all creatures are hermaphrodites.
  • In the novel and manga adaption of the Ring (Ringu), Sadako Yamamura is told to be a hermaphrodite; that is, she has no uterus, but she identifies as female and has testes along with breasts.
  • In the early 1990s, Channel 4, a British television channel, showed a four-minute program in the late evening called "Hermaphrodite Bikini", where a few hermaphrodites danced naked to music.
  • In the video game, Zeno Clash, one of the main characters, Father-Mother is a initially believed to be a hermaphrodite. This belief is proven to be false near the conclusion of the game.
  • In the anime series, Yu-Gi-Oh! GX, the character/Duel Monsters spirit Yubel is a hermaphrodite. In the dub, however, she is censored and said to be female.
  • Most life forms on the fictional planet Darwin IV are hermaphrodites.
  • The short story "Cinismo" by Argentinean writer Sergio Bizzio, (in Spanish [1]) and the 2007 movie XXY, based on that story.
  • In the anime adaptation of Black Butler (Kuroshitsuji), the maid, Angela, is a hermaphrodite; she and 'Ash' are the same person.
  • In the futuristic novel Crygender (1992), by Thomas T. Thomas, the title character is a wealthy hermaphrodite.[7]
  • Lois McMaster-Bujold's series about Miles Vorkosigan include Hermaphorodites that were genetically engineered on the planet Beta, the home planet of Miles' mother. One Herm figures prominently in a couple of the novels. (published by Baen Books.)
  • In South Park Eric Cartman's mom is at first said to have been a hermaphrodite, and therefore actually his father and mother, however this was proven wrong in season 14 when they revealed who his real father actually was.
  • In the soap opera Passions, the character Valerie Davis, played by Daphnee Duplaix, is a hermaphrodite.

[edit] See also

[edit] References

[edit] Notes

  1. ^ Merriam-Webster Dictionary
  2. ^ Word origin and history: Hermaphrodite Word-Origins.com
  3. ^ Intersex Society of North America | A world free of shame, secrecy, and unwanted genital surgery
  4. ^ a b c d Barrows, Edward M. (2001). Animal behavior desk reference: a dictionary of animal behavior, ecology, and evolution (2nd ed.). Boca Raton, Fla: CRC Press. p. 317. ISBN 0849320054. OCLC 299866547. 
  5. ^ Leyner, Mark; Goldberg M.D., Billy (2005). Why Do Men Have Nipples?: Hundreds of Questions You'd Only Ask a Doctor After Your Third Martini. New York: Three Rivers Press. ISBN 1400082315. OCLC 57722472. 
  6. ^ Ovid, Metamorphoses, Book IV: The story of Hermaphroditus and Salmacis.
  7. ^ Crygender by Thomas T Thomas. Google books. 1992-01. ISBN 9780671721015. http://books.google.com/?id=UCppPKUoTTcC. Retrieved January 24, 2010. 

[edit] Bibliography

[edit] Further reading

[edit] External links



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