Oogamy: Difference between revisions

Oogamy is found in almost all animal species that [[Sexual reproduction|reproduce sexually]].<ref>{{Cite book|last=Bell|first=Graham|url=https://books.google.com/books?id=Xzv3DwAAQBAJ&q=the+evolution+of+sexual+reproduction+is+important+to+the+evolution+of+sex|title=The Masterpiece of Nature: The Evolution and Genetics of Sexuality|date=2019-11-28|publisher=Routledge|isbn=978-1-000-49744-1|pages=63|language=en|author-link=Graham Bell (biologist)}}</ref><ref name=":0Dusenbery-2009" /> There are exceptions, such as the [[opiliones]] that have immobile sperm.<ref>{{Cite book|last1=Leonard|first1=Janet|url=https://books.google.com/books?id=wmlnDAAAQBAJ&dq=oogamy+in+animals&pg=PA18|title=The Evolution of Primary Sexual Characters in Animals|last2=Cordoba-Aguilar|first2=Alex|date=2010-07-19|publisher=Oxford University Press, USA|isbn=978-0-19-532555-3|pages=18–19|language=en}}</ref>

It is generally accepted that [[isogamy]] is the ancestral state<ref>{{Cite book|last1=Pitnick|first1=Scott S.|url=https://books.google.com/books?id=kctYNbO1fE0C&q=evolution+of+anisogamy|title=Sperm Biology: An Evolutionary Perspective|last2=Hosken|first2=Dave J.|last3=Birkhead|first3=Tim R.|date=2008-11-21|publisher=Academic Press|isbn=978-0-08-091987-4|pages=43–44|language=en}}</ref> and that oogamy evolves from isogamy through anisogamy.<ref>{{Cite book|last=Kumar|first=Awasthi & Ashok|url=https://books.google.com/books?id=r0h1DwAAQBAJ&dq=isogamy+generally+accepted&pg=PA363|title=Textbook of Algae|publisher=Vikas Publishing House|isbn=978-93-259-9022-7|pages=363|language=en}}</ref><ref>{{Cite book|last1=Dusenbery|first1=David B.|url=https://books.google.com/books?id=QCrimQJu1RAC|title=Living at Micro Scale: The Unexpected Physics of Being Small|last2=Dusenbery|first2=Professor of Biology Emeritus David B.|date=2009|publisher=Harvard University Press|isbn=978-0-674-03116-6|pages=309|language=en}}</ref><ref>{{Cite journal|last1=Hörandl|first1=Elvira|last2=Hadacek|first2=Franz|date=August 2020|title=Oxygen, life forms, and the evolution of sexes in multicellular eukaryotes|journal=Heredity|language=en|volume=125|issue=1|pages=1–14|doi=10.1038/s41437-020-0317-9|pmid=32415185|issn=1365-2540|pmc=7413252}}</ref> When oogamy has evolved, males and females typically differ in many aspects. Oogamy evolved before the transition from [[External fertilization|external]] to [[internal fertilization]].<ref>{{Cite journal|last1=Nozaki|first1=Hisayoshi|last2=Yamada|first2=Toshihiro K.|last3=Takahashi|first3=Fumio|last4=Matsuzaki|first4=Ryo|last5=Nakada|first5=Takashi|date=2014-03-03|title=New "missing link" genus of the colonial volvocine green algae gives insights into the evolution of oogamy|url=https://doi.org/10.1186/1471-2148-14-37|journal=BMC Evolutionary Biology|volume=14|issue=1|pages=37|doi=10.1186/1471-2148-14-37|issn=1471-2148|pmc=4015742|pmid=24589311}}</ref>{{Primary source inline|date=September 2021}}<ref name=":0Dusenbery-2009">{{Cite book|last=Dusenbery|first=David B.|url=https://books.google.com/books?id=9hgtEAAAQBAJ&dq=oogamy+and+internal+fertilization&pg=PA326|title=Living at Micro Scale: The Unexpected Physics of Being Small|date=2009|publisher=Harvard University Press|isbn=978-0-674-06021-0|pages=326|language=en}}</ref>