Anisogamy

Anisogamy

Anisogamy (also called heterogamy) refers to a form of sexual reproduction involving gametes of different sizes. The smaller gamete is considered to be male (sperm cell) whereas the larger gamete is regarded as female (egg cell).

There are several types of anisogamy. Both gametes may be flagellated and thus motile. Conversely, neither of the gametes may be flagellated. This situation occurs for example in some algae and plants. In the red alga "Polysiphonia", large non-motile egg cells are fertilized by small, non-motile spermatia. In flowering plants, the gametes are non-motile cells within gametophytes.

The form of heterogamy that occurs in animals is oogamy. In oogamy, a large, non-motile egg cell (ovum) is fertilized by a small, motile sperm cell (spermatozoon). The large egg cell is optimized for longevity, whereas the small sperm cell is optimized for motility and speed. The size and resources of the egg cell allow for the production of pheromones, which attract the swimming sperm cells.

See also

*Gamete
*Isogamy


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Look at other dictionaries:

  • anisogamy — n. 1. (biology) reproduction by the union or fusion of two differing gametes (especially differing in size). [WordNet 1.5] …   The Collaborative International Dictionary of English

  • anisogamy — anisogamy. См. анизогамия. (Источник: «Англо русский толковый словарь генетических терминов». Арефьев В.А., Лисовенко Л.А., Москва: Изд во ВНИРО, 1995 г.) …   Молекулярная биология и генетика. Толковый словарь.

  • anisogamy — anizogamija statusas T sritis augalininkystė apibrėžtis Dviejų labai skirtingų (formos, dydžio ar kitu atžvilgiu) gametų susiliejimas. atitikmenys: angl. anisogamy rus. анизогамия ryšiai: sinonimas – heterogamija …   Žemės ūkio augalų selekcijos ir sėklininkystės terminų žodynas

  • anisogamy — noun see anisogamous …   New Collegiate Dictionary

  • anisogamy — reproductive products of unequal size (eggs and sperm) …   Dictionary of ichthyology

  • anisogamy — n. [Gr. anisos, unequal; gamos, marriage] Gametes when fusing during fertilization vary in size, shape and behavior; see heterogamy …   Dictionary of invertebrate zoology

  • anisogamy — Mode of sexual reproduction in which the two gametes are of different sizes …   Dictionary of molecular biology

  • anisogamy — /an uy sog euh mee/, n. Biol. the union of anisogametes. [1890 95; ANISO + GAMY] * * * …   Universalium

  • anisogamy — noun A form of sexual bonding involving partners of unusually widely differing ages …   Wiktionary

  • anisogamy — Fusion of two gametes unequal in size or form; fertilization as distinguished from isogamy or conjugation. [aniso + G. gamos, marriage] * * * an·isog·a·my (an″i sogґə me) [aniso + Gr. gamos marriage] in the most restrictive sense,… …   Medical dictionary

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