Hermaphrodite
In
zoology and
botany, a hermaphrodite is an organism that possesses both
male and
female sex organs during its life. In many species, hermaphroditism is a common part of the life-cycle. Generally, hermaphroditism occurs in the invertebrates, although it occurs in a fair number of
fish, and to a lesser degree in other
vertebrates.
The term "hermaphrodite" has historically been used to describe people with ambiguous genitalia or biological sex. The broader term
intersexual is often used and is preferred by many such individuals and medical professionals.
Encyclopedia
- For the Julia Ward Howe novel, see The Hermaphrodite.
- For hermaphroditism in humans, see Intersexuality.
- For the type of electrical connector, see Gender of connectors and fasteners.
In
zoology and
botany, a
hermaphrodite is an organism that possesses both
male and
female sex organs during its life. In many species, hermaphroditism is a common part of the life-cycle. Generally, hermaphroditism occurs in the invertebrates, although it occurs in a fair number of
fish, and to a lesser degree in other
vertebrates.
The term "hermaphrodite" has historically been used to describe people with ambiguous genitalia or biological sex. The broader term
intersexual is often used and is preferred by many such individuals and medical professionals. However, some hermaphrodites do not like the sexual connotations and misunderstanding of the word "Intersexed" and thus prefer to use hermaphrodite instead. The term is still used by the pornography industry, though often as a synonym for transsexual, as true human intersexuals are rare.
In animals
Sequential hermaphrodites
Sequential hermaphrodites are organisms born as one sex which later change into the other sex.
- Protandry: When the organism starts as a male, and changes sex to a female later in life.
- Example: The seabasses . These are a highly sought food fish complex made up of primarily groupers. Since even a small male can produce more than enough sperm to fertilize a huge number of eggs, while a female's egg output increases greatly with an increase in size, this strategy makes sense for an organism where over 90% of the eggs laid will not result in a fish that reaches sexual maturity. It has been shown that fishing pressure actually is causing a change in 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 artificial selection.
- Protogyny: When the organism starts as a female, and changes sex to a male later in life.
- Example: Wrasses are reef fish that tend to have three distinct sexual types. Small females, immature males and supermales. The small females and the immature males have identical colorations. The supermale is usually brightly colored, and there is only one in a given area of the reef. This supermale dominates the other wrasses of the species, having the choice of females to mate with. When the supermale dies, the largest wrasse in the area, male or female, becomes the new supermale.
Simultaneous hermaphrodites
A simultaneous hermaphrodite is an organism that has both male and female sexual organs at the same time as an adult. Usually, self-fertilization does not occur.
- 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 synchronous hermaphrodite. Although they possess ovaries and testes, they have a protective mechanism against self fertilization and can only function as a single sex at one time. Sexual reproduction occurs when two worms meet and exchange gametes, copulating on damp, wet nights during warm seasons. Fertilized eggs are protected by a cocoon, which is buried on or near the surface of the ground.
Gonadal dysgenesis
Gonadal dysgenesis is a type of
intersexuality
formerly known as "True Hermaphroditism", occurs in about one percent of mammals , but it is extremely rare for both sets of sexual organs to be functional; usually neither set is functional. In many cases, these manifestations are altered, sometimes only cosmetically, to resemble standard
male or
female anatomy shortly after birth.
Fetal hermaphroditism in humans
Sigmund Freud held fetal hermaphroditsm to be a fact of the physiological development of humans. He was so certain of this, in fact, that he based much of his theory of innate bisexuality on that assumption. This was later revealed to be untrue .
In plants
Hermaphrodite is used in
botany to describe a
flower that has both
staminate and
carpelate parts that are self fertile or self pollenizing. Hermaphrodism in plants is more complex than in animals because plants can have hermaphroditic flowers as described, or unisexual flowers with both male and female types developing on the
same individual—a closer analogy to animal hermaphrodism. However, this latter condition constitutes
monoecy in plants, and is especially common to the
conifers, while occurring in only about 7% of angiosperm species .
Etymology
The term "hermaphrodite" derives from
Hermaphroditus, the son of
Hermes and
Aphrodite in
Greek mythology, who was fused with a
nymph, resulting in one possessing physical traits of both sexes. Thus Hermaphroditus was, by the modern terminology, a simultaneous hermaphrodite. The mythological figure of Tiresias, who figures in the
Oedipus cycle as well as the
Odyssey, was a sequential hermaphrodite, having been changed from a man to a woman and back by the gods.
See also
References
Further reading
- M.M. Grumbach, and F.A. Conte. 1998. "Disorders of sex differentiation." in Williams Textbook of Endocrinology, eds. J.D. Wilson, D.W. Foster, H.M. Kronenberg, and P.R. Larsen, .
- Molnar, Sebastian. 2004. , internet version posted February 17, 2004.
