Definition

1. Noun:
   • (Biology): A type of sexual reproduction involving the fusion of two gametes that differ in size and/or form. It is the condition in which the reproducing cells (gametes) are dissimilar, most commonly observed as a difference in size between the male and female gametes.

Usage

• General Statement: "Anisogamy" is a technical biological term used to describe the fundamental sexual reproductive strategy in many species, including humans, where small, motile sperm fertilize larger, non-motile eggs.
• In Evolutionary Biology: The term is central to discussions about the evolution of sex roles and sexual selection, as the size difference in gametes is considered the starting point for these phenomena.

Examples

• In a Scientific Context:
  • The evolution of anisogamy is a major transition in evolutionary history.
  • Anisogamy is characterized by the production of two types of gametes: microgametes (sperm) and macrogametes (eggs).
• In a Comparative Biology Context:
  • Most animals and many plants exhibit anisogamy, unlike some algae which exhibit isogamy (fusion of similar gametes).

Advanced Usage

• Theoretical Context: In evolutionary theory, "anisogamy" is often discussed as the basis for Bateman's principle and the subsequent development of different mating strategies between sexes.
  • The theory suggests that anisogamy sets the stage for competition among males and choosiness among females.

Variants and Related Words

• Anisogamous (adjective): Relating to or characterized by anisogamy.
  • Anisogamous reproduction is the norm in vertebrates.
• Isogamy (noun): The fusion of similar gametes, which is the contrasting condition to anisogamy.
• Oogamy (noun): A form of anisogamy where the female gamete is large and non-motile (egg) and the male gamete is small and motile (sperm). Oogamy is considered an extreme form of anisogamy.

Synonyms

• Heterogamy: In some biological contexts, this can be used synonymously with anisogamy, specifically referring to the fusion of dissimilar gametes. (Note: "Heterogamy" can have other meanings in botany and sociology).

Antonyms

• Isogamy: Reproduction by the fusion of similar gametes.

Noun

1. (biology) reproduction by the union or fusion of two differing gametes (especially differing in size)