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

Zoology

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. Sequential hermaphrodism is important in understanding behavioral ecology and life history theory.

Sequential hermaphrodites fall into two broad categories:

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.

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.

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.

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.

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).

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. He based much of his theory of innate sexuality on that assumption. 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.

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]

In fiction

See also

References

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. 4.0 4.1 4.2 4.3 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. 

Bibliography

Further reading

External links