Reproduction And Development Codexery

Asexual reproduction

Reproduction without gamete fusion, producing genetically identical offspring.

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Asexual reproduction does not involve the fusion of gametes or change in chromosome number.[1] Offspring inherit the full set of genes from a single parent and are genetically and physically similar or identical to that parent.[1] For unicellular life forms like archaea and bacteria, asexual reproduction serves as their dominant method of producing offspring.[1]

Quick Facts

Primary organisms
  • Archaea
  • bacteria
  • many protists
  • plants
  • animals
  • fungi
Common vertebrate form
Parthenogenesis
Key processes
  • Binary fission
  • budding
  • vegetative propagation
  • spore formation
  • fragmentation
  • parthenogenesis

Facts from the source article.

Key facts and history

Parthenogenesis has been documented in over 2,000 species, including water fleas, rotifers, aphids, and some reptiles, amphibians, and fish.[2] The largest species documented reproducing parthenogenically is the Komodo dragon, reaching 10 feet and over 300 pounds.[3][4] Female Komodo dragons have both male and female sex chromosomes and can reproduce asexually when no males are present.[4] Asexual reproduction in Komodo dragons only results in sons.[4]

Some plants reproduce asexually through vegetative propagation, forming new individuals without seeds or spores.[5] Asexual reproduction is also employed by numerous eukaryotic organisms, which encompass plants, animals, and fungi.[1] Among vertebrates, parthenogenesis stands as the prevalent asexual method, typically employed when mating prospects are scarce.[1] Mitosis is used by fungi and certain algae to generate mitospores, a process known as true asexual spore formation.[6]

Planarians, annelid worms, and sea stars are examples of animals that utilize fragmentation for reproduction.[7]

What the cited sources add

A 2006 Live Science article reported that a baby Komodo dragon hatched from an egg produced asexually at the London Zoo.[8] Whiptail lizards generate all-female offspring through asexual reproduction, while Komodo dragons can reproduce either sexually or asexually depending on conditions.[8] A Scientific American article stated that parthenogenesis is rare among vertebrates, with only about 70 backboned species capable of it, roughly 0.1 percent of all vertebrates.[9] The Komodo dragon account from Animals explained that while asexual reproduction allows females to replenish their population, it has the drawback of only producing sons.[4]

A 2006 Live Science article raised the question of whether keeping males and females separate could cause a switch from sexual to asexual reproduction, potentially decreasing genetic diversity.[8]

References

  1. Wikipedia, "Asexual reproduction" (CC BY-SA 4.0), which cites: Engelstädter, "Asexual but Not Clonal: Evolutionary Processes in Automictic Populations", Genetics, June 2017, p. 993–1009 (original not read by us) en.wikipedia.org
  2. Wikipedia, "Asexual reproduction" (CC BY-SA 4.0), which cites: "parthenogenesis Definition, Types, & Facts", Encyclopedia Britannica (original not read by us) en.wikipedia.org
  3. Wikipedia, "Asexual reproduction" (CC BY-SA 4.0), which cites: Yam, "Strange but True: Komodo Dragons Show that "Virgin Births" Are Possible", Scientific American; "Komodo dragon", Animals, 2010-09-10 (we also read that source) en.wikipedia.org
  4. "Komodo dragon", Animals, 2010-09-10. facts only, no text reused. nationalgeographic.com
  5. Wikipedia, "Asexual reproduction" (CC BY-SA 4.0), which cites: "Asexual Reproduction", Ucmp.berkeley.edu (original not read by us) en.wikipedia.org
  6. Wikipedia, "Asexual reproduction" (CC BY-SA 4.0), which cites: "Plant." Britannica Academic, Encyclopædia Britannica, 15 Jun. 2021. Accessed 20 Jan. 2022.; Card, V. (2016). Algae. In M. S. Hill (Ed.), Biology (2nd ed., Vol. 1, pp. 21–23). Macmillan Reference USA.; "Fungus." Britannica Academic, Encyclopædia Britannica, 4 Oct. 2018. Accessed 20 Jan. 2022. (original not read by us) en.wikipedia.org
  7. Wikipedia, "Asexual reproduction" (CC BY-SA 4.0), which cites: "Invertebrate Zoology", Brooks / Cole, 2004, p. 434–441; "Invertebrate Zoology", Brooks / Cole, 2004, p. 434–441 (we also read that source) en.wikipedia.org
  8. Bryner, "Female Komodo Dragon Has Virgin Births", Live Science, 20 December 2006. facts only, no text reused. livescience.com
  9. Yam, "Strange but True: Komodo Dragons Show that "Virgin Births" Are Possible", Scientific American. facts only, no text reused. scientificamerican.com

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Asexual reproduction (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

Related entries

Sexual reproduction

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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