From Surf Wiki (app.surf) — the open knowledge base

Oogamy

Form of sexual reproduction

Oogamy in animals: small, motile sperm on the surface of an ovum

Oogamy is a type of sexual reproduction where the gametes differ greatly in both size and form. In oogamy in animals the large female gamete (also known as the ovum) is immotile, while the small male gamete (also known as a sperm) is mobile. Most sexually reproducing species – animals, land plants and some algae, are oogamous. It is generally accepted that isogamy is the ancestral state, from which oogamy evolved at least twenty times via anisogamy. Once oogamy evolves, males and females typically differ in various aspects. Internal fertilization may have originated from oogamy, although some studies suggest certain species may have evolved before the transition from external to internal fertilization. In streptophytes, oogamy occurred before the split from green algae.

Occurrence

Oogamy is found in almost all animal species that reproduce sexually. There are exceptions, such as the opiliones that have immobile sperm.

Oogamy is found in all land plants, and in some red algae, brown algae and green algae. Oogamy is favored in land plants because only one gamete has to travel through harsh environments outside the plant. Oogamy is also present in oomycetes.

Etymology

The term oogamy was first used in the year 1888. It derives from the Greek noun "oon" (ΩΟΝ = egg) and the Greek verb "gameo" (ΓΑΜΕΩ → ΓΑΜΩ = to have sex/to reproduce) and eventually means "reproduction through eggs".

Evolution

Main article: Evolution of sexual reproduction

The ancestral state of sexual reproduction is probably isogamy, in which both gametes are identical, from which oogamy is thought to have evolved multiple times through anisogamy. When oogamy has evolved, males and females typically differ in many aspects. Oogamy evolved before the transition from external to internal fertilization.

In streptophytes, oogamy occurred before the split from green algae.

References

(2019-10-10). "The Biology of Reproduction". Cambridge University Press.
Bell, Graham. (2019-11-28). "The Masterpiece of Nature: The Evolution and Genetics of Sexuality". Routledge.
Dusenbery, David B.. (2009). "Living at Micro Scale: The Unexpected Physics of Being Small". Harvard University Press.
(2010-07-19). "The Evolution of Primary Sexual Characters in Animals". Oxford University Press, USA.
Simpson, Michael G.. (2010-07-19). "Plant Systematics". Academic Press.
(2005). "Biology of Plants". W. H. Freeman.
(2020). "An overview on the biology and phylogeny of the early-diverging oomycetes". Philippine Journal of Systematic Biology.
"Definition of OOGAMY".
"Multicellularity: evolution and the egg". Nature.
(2008-11-21). "Sperm Biology: An Evolutionary Perspective". Academic Press.
Kumar, Awasthi & Ashok. "Textbook of Algae". Vikas Publishing House.
(August 2020). "Oxygen, life forms, and the evolution of sexes in multicellular eukaryotes". Heredity.
(2014). "New "missing link" genus of the colonial volvocine green algae gives insights into the evolution of oogamy". BMC Evolutionary Biology.
(2014-07-08). "Evolution of Sexes from an Ancestral Mating-Type Specification Pathway". PLOS Biology.

Info: Wikipedia Source

This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.

reproductive-system germ-cells

Want to explore this topic further?

Ask Mako anything about Oogamy — get instant answers, deeper analysis, and related topics.

Research with Mako

Free with your Surf account

Content sourced from Wikipedia, available under CC BY-SA 4.0.

This content may have been generated or modified by AI. CloudSurf Software LLC is not responsible for the accuracy, completeness, or reliability of AI-generated content. Always verify important information from primary sources.

Report