What does isogamy mean?
Isogamy is a form of sexual reproduction in which the gametes involved are morphologically identical. Because the gametes cannot be distinguished by size or structure, they are also not readily classified as female and male types. The term is especially common in mycology, algology, and protist biology. It contrasts with anisogamy, where gametes differ in form or size, and with the more specialized form known as oogamy, in which a large egg is fertilized by a small sperm. Isogamy is scientifically notable because it presents a reproductive system without the visible cellular differences that distinguish gametes in many other organisms. The word also provides a useful example of how biological terminology expresses precise relationships: its prefix refers to equality, while the suffix refers to sexual union or reproduction.
nounA form of sexual reproduction in which the participating gametes are morphologically identical, without differentiation by size or form.
- A form of sexual reproduction in which the participating gametes are indistinguishable in size, structure, and behavior, so that they cannot be classified as distinct male and female gametes.
"Some algae reproduce by isogamy, producing gametes that are alike in size and structure."
"The green alga reproduces sexually through isogamy."
"Researchers studied isogamy in several lineages of microscopic algae."
Rare in practice; singular isogamy is much more common.
"These isogamies involve morphologically identical gametes."
In isogamy, biology gives us the original power couple: two gametes so alike that neither has a reproductive advantage.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does isogamy come from?
The word was formed from Greek roots: isos, meaning “equal,” and gamos, meaning “marriage” or reproductive union. Its development follows the same conceptual distinction seen in related biological terms, especially the contrast with anisogamy, whose prefix denotes inequality or difference. Terms such as autogamy, allogamy, and heterogamy share the second element and are organized according to the origins or relationships of the gametes involved.
Related word forms
How isogamy is actually used
This is chiefly a technical biological term, especially used in discussions of algae, fungi, and protists. It contrasts with anisogamy, in which gametes differ noticeably in form or size.
Easily confused with isogamy
Isogamy involves morphologically identical gametes, whereas anisogamy involves gametes that differ in size or form.
Oogamy is a specialized form of anisogamy in which a large egg is fertilized by a smaller sperm.