Sexual reproduction involving a large, female gamete and a small, male gamete
Anisogamy is a form of sexual reproduction that involves the union or fusion of two gametes that differ in size and/or form. The smaller gamete is male, a sperm cell, whereas the larger gamete is female, typically an egg cell. Anisogamy is predominant among multicellular organisms.[1] In both plants and animals, gamete size difference is the fundamental difference between females and males.[2]
Anisogamy most likely evolved from isogamy.[3] Since the biological definition of male and female is based on gamete size, the evolution of anisogamy is viewed as the evolutionary origin of male and female sexes.[4][5] Anisogamy is an outcome of
both natural selection and sexual selection,[6] and led the sexes to different primary and secondary sex characteristics[7] including sex differences in behavior.[8]
Geoff Parker, Robin Baker, and Vic Smith were the first to provide a mathematical model for the evolution of anisogamy that was consistent with modern evolutionary theory.[4] Their theory was widely accepted but there are alternative hypotheses about the evolution of anisogamy.[9][1]
^ abLehtonen, J.; Kokko, Hanna; Parker, Geoff A. (October 2016). "What do isogamous organisms teach us about sex and the two sexes?". Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences. 371 (1706). doi:10.1098/rstb.2015.0532. PMC 5031617. PMID 27619696.
^Davies, Nicholas B.; Krebs, John R. (2009-07-17). An Introduction to Behavioural Ecology. John Wiley & Sons. pp. 175–206. ISBN 978-1-4443-1402-1. Archived from the original on 2024-03-28. Retrieved 2021-06-15.
^Cite error: The named reference Pitnick-2008 was invoked but never defined (see the help page).
^ abLehtonen, Jussi (2021-03-05). "The Legacy of Parker, Baker and Smith 1972: Gamete Competition, the Evolution of Anisogamy, and Model Robustness". Cells. 10 (3): 573. doi:10.3390/cells10030573. ISSN 2073-4409. PMC 7998237. PMID 33807911.
^Togashi, Tatsuya; Bartelt, John L.; Yoshimura, Jin; Tainaka, Kei-ichi; Cox, Paul Alan (2012-08-21). "Evolutionary trajectories explain the diversified evolution of isogamy and anisogamy in marine green algae". Proceedings of the National Academy of Sciences of the United States of America. 109 (34): 13692–13697. Bibcode:2012PNAS..10913692T. doi:10.1073/pnas.1203495109. ISSN 0027-8424. PMC 3427103. PMID 22869736.
^Leonard, Janet; Cordoba-Aguilar, Alex (2010-07-19). The Evolution of Primary Sexual Characters in Animals. Oxford University Press, USA. pp. 18–20. ISBN 978-0-19-532555-3. Archived from the original on 2024-03-28. Retrieved 2021-08-19.
^Encyclopedia of Animal Behavior. Vol. 2. Academic Press. 2019-01-21. p. 7. ISBN 978-0-12-813252-4. Archived from the original on 2024-03-28. Retrieved 2021-11-27.
^Andersson, Malte (2019-12-31). Sexual Selection. Princeton University Press. ISBN 978-0-691-20727-8. Archived from the original on 2024-03-28. Retrieved 2021-11-27.
^Majerus, M. E. N. (2003). Sex Wars: Genes, Bacteria, and Biased Sex Ratios. Princeton University Press. pp. 7–8. ISBN 978-0-691-00981-0. Archived from the original on 2024-03-28. Retrieved 2021-08-19.
Anisogamy is a form of sexual reproduction that involves the union or fusion of two gametes that differ in size and/or form. The smaller gamete is male...
larger than the male and has no ability to move. Oogamy is a form of anisogamy. There is an argument that this pattern was driven by the physical constraints...
[citation needed] The evolution of anisogamy led to the evolution of male and female function. Before the evolution of anisogamy, mating types in a species were...
zygote. It is generally accepted that isogamy is an ancestral state for anisogamy and that isogamy was the first stage in the evolution of sexual reproduction...
of species, the gametes are of different sizes, a condition known as anisogamy or heterogamy that applies to humans and other mammals. The human ovum...
Oogamy is a form of anisogamy where the gametes differ in both size and form. In oogamy the large female gamete (also known as ovum) is immotile, while...
are behavioral and population genetic. The genetic aspect states that anisogamy arose to maximize contact rate between gametes. The behavioral aspect...
paramesonephric duct, a mesonephric duct, and a genital tubercle. The evolution of anisogamy may have contributed to the evolution of simultaneous hermaphroditism...
ascertained, there are several theories as to how monogamy may have evolved. Anisogamy is a form of sexual reproduction which involves the fusion of two unequally-sized...
2020-10-05 Kumar R, Meena M, Swapnil P (2019). "Anisogamy". In Vonk J, Shackelford T (eds.). Anisogamy. Encyclopedia of Animal Cognition and Behavior....
(biology) Mating type Sexual reproduction Evolution of sexual reproduction Anisogamy Isogamy Germ cell Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete...
Gonochorism owes its origin to the evolution of anisogamy, but it is unclear if the evolution of anisogamy first led to hermaphroditism or gonochorism.: 213 ...
or the environment changes drastically. Both isogamy and anisogamy occur in Protozoa, anisogamy being the more common form of sexual reproduction. Protozoans...
possible in some species, where in others it is absent. The evolution of anisogamy possibly contributed to the evolution of Simultaneous hermaphroditism...
(biology) Mating type Sexual reproduction Evolution of sexual reproduction Anisogamy Isogamy Germ cell Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete...
(biology) Mating type Sexual reproduction Evolution of sexual reproduction Anisogamy Isogamy Germ cell Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete...
(biology) Mating type Sexual reproduction Evolution of sexual reproduction Anisogamy Isogamy Germ cell Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete...
or a palmella stage, while its sexual reproduction is through isogamy, anisogamy or oogamy. Most species are obligate phototrophs but C. reinhardtii and...
dikaryon and/or diploid stage of the life cycle. Mating types likely predate anisogamy, and sexes evolved directly from mating types or independently in some...
(biology) Mating type Sexual reproduction Evolution of sexual reproduction Anisogamy Isogamy Germ cell Meiosis Gametogenesis Spermatogenesis Oogenesis Gamete...