Spol

Spol je biološka osobina koja određuje da li organizam koji se spolno razmnožava proizvodi muške ili ženske gamete.^[1]^[2]^[3]^[4] Tokom spolnog razmnožavanja, muška i ženska gameta se spajaju u zigotu, koja se razvija u potomstvo koje nasljeđuje osobine od svakog roditelja. Po konvenciji, organizmi koji proizvode manje, pokretljivije gamete (spermatozoide) nazivaju se muškima, dok se organizmi koji proizvode veće, nepokretne gamete (jajne ćelije) nazivaju ženskim.^[5] Organizam koji proizvodi oba tipa gameta je hermafrodit.^[3]^[6]

Kod nehermafroditskih vrsta, spol pojedinca se određuje kroz jedan od nekoliko bioloških sistema za određivanje spola. Većina vrsta sisara ima XY sistem određivanja spola, gdje mužjak obično nosi X i Y hromozom (XY), a ženka obično nosi dva X hromozoma (XX). Drugi sistemi hromozomskog određivanja pola kod životinja uključuju ZW sistem kod ptica i XO sistem kod nekih insekata.^[7] Različiti ekološki sistemi uključuju određivanje spola ovisno o temperaturi kod gmizavaca i rakova.^[8]

Mužjak i ženka neke vrste mogu biti fizički slični (seksualni monomorfizam) ili imati fizičke razlike (seksualni dimorfizam). Kod spolno dimorfnih vrsta, uključujući većinu ptica i sisara, spol jedinke se obično identificira posmatranjem seksualnih karakteristika te jedinke. Seksualni odabir ili izbor partnera može ubrzati evoluciju razlika među spolovima.

Izrazi mužjak i ženka obično se ne primjenjuju na spolno nediferencirane vrste kod kojih su jedinke izomorfne (izgledaju isto) i gamete su izogamne (ne razlikuju se po veličini i obliku), kao što je zelena alga Ulva lactuca. Neke vrste funkcionalnih razlika između jedinki, kao što su gljive,^[9] mogu se nazvati tipovima parenja.^[10]

^ Stevenson A, Waite M (2011). "Sex". Concise Oxford English Dictionary: Book & CD-ROM Set. OUP Oxford. str. 1302. ISBN 978-0-19-960110-3. Pristupljeno 23. 3. 2018. Sex: Either of the two main categories (male and female) into which humans and most other living things are divided on the basis of their reproductive functions. The fact of belonging to one of these categories. The group of all members of either sex.
^ Mills A (1. 1. 2018). "Sex and Reproduction". Biology of Sex (jezik: engleski). University of Toronto Press. str. 43–45. ISBN 978-1-4875-9337-7. Pristupljeno 3. 10. 2023.
^ ^a ^b Purves WK, Sadava DE, Orians GH, Heller HC (2000). Life: The Science of Biology. Macmillan. str. 736. ISBN 978-0-7167-3873-2. Pristupljeno 23. 3. 2018. A single body can function as both male and female. Sexual reproduction requires both male and female haploid gametes. In most species, these gametes are produced by individuals that are either male or female. Species that have male and female members are called dioecious (from the Greek for 'two houses'). In some species, a single individual may possess both female and male reproductive systems. Such species are called monoecious ("one house") or hermaphroditic.
^ De Loof, Arnold (31. 1. 2018). "Only two sex forms but multiple gender variants: How to explain?". Communicative & Integrative Biology. 11 (1): e1427399. doi:10.1080/19420889.2018.1427399. ISSN 1942-0889. PMC 5824932. PMID 29497472.
^ Kokko H, Jennions M (2012). "Sex differences in parental care". u Royle NJ, Smiseth PT, Kölliker M (ured.). The Evolution of Parental Care (jezik: engleski). Oxford University Press. str. 103. ISBN 978-0-19-969257-6. The answer is that there is an agreement by convention: individuals producing the smaller of the two gamete types – sperm or pollen – are males, and those producing larger gametes – eggs or ovules – are females.
^ Avise JC (2011). "Two sexes in one". Hermaphroditism: A Primer on the Biology, Ecology, and Evolution of Dual Sexuality (jezik: engleski). Columbia University Press. str. 1–7. ISBN 978-0-231-52715-6. Pristupljeno 18. 9. 2020.
^ Blackmon H, Ross L, Bachtrog D (januar 2017). "Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects". The Journal of Heredity. 108 (1): 78–93. doi:10.1093/jhered/esw047. ISSN 0022-1503. PMC 6281344. PMID 27543823.
^ Hake L, O'Connor C (2008). "Genetic Mechanisms of Sex Determination | Learn Science at Scitable". Nature Education. 1 (1): 25. Arhivirano s originala, 19. 8. 2017. Pristupljeno 13. 4. 2021.
^ Moore D, Robson JD, Trinci AP (2020). 21st Century guidebook to fungi (2 izd.). Cambridge University Press. str. 211–228. ISBN 978-1-108-74568-0.
^ Kumar R, Meena M, Swapnil P (2019). "Anisogamy". u Vonk J, Shackelford T (ured.). Encyclopedia of Animal Cognition and Behavior. Cham: Springer International Publishing. str. 1–5. doi:10.1007/978-3-319-47829-6_340-1. ISBN 978-3-319-47829-6. Anisogamy can be defined as a mode of sexual reproduction in which fusing gametes, formed by participating parents, are dissimilar in size.

[Stevenson-2011-1] Stevenson A, Waite M (2011). "Sex". Concise Oxford English Dictionary: Book & CD-ROM Set. OUP Oxford. str. 1302. ISBN 978-0-19-960110-3. Pristupljeno 23. 3. 2018. Sex: Either of the two main categories (male and female) into which humans and most other living things are divided on the basis of their reproductive functions. The fact of belonging to one of these categories. The group of all members of either sex.

[2] Mills A (1. 1. 2018). "Sex and Reproduction". Biology of Sex (jezik: engleski). University of Toronto Press. str. 43–45. ISBN 978-1-4875-9337-7. Pristupljeno 3. 10. 2023.

[Purves-2000-3] Purves WK, Sadava DE, Orians GH, Heller HC (2000). Life: The Science of Biology. Macmillan. str. 736. ISBN 978-0-7167-3873-2. Pristupljeno 23. 3. 2018. A single body can function as both male and female. Sexual reproduction requires both male and female haploid gametes. In most species, these gametes are produced by individuals that are either male or female. Species that have male and female members are called dioecious (from the Greek for 'two houses'). In some species, a single individual may possess both female and male reproductive systems. Such species are called monoecious ("one house") or hermaphroditic.

[4] De Loof, Arnold (31. 1. 2018). "Only two sex forms but multiple gender variants: How to explain?". Communicative & Integrative Biology. 11 (1): e1427399. doi:10.1080/19420889.2018.1427399. ISSN 1942-0889. PMC 5824932. PMID 29497472.

[Royle-2012-5] Kokko H, Jennions M (2012). "Sex differences in parental care". u Royle NJ, Smiseth PT, Kölliker M (ured.). The Evolution of Parental Care (jezik: engleski). Oxford University Press. str. 103. ISBN 978-0-19-969257-6. The answer is that there is an agreement by convention: individuals producing the smaller of the two gamete types – sperm or pollen – are males, and those producing larger gametes – eggs or ovules – are females.

[Avise-2011-6] Avise JC (2011). "Two sexes in one". Hermaphroditism: A Primer on the Biology, Ecology, and Evolution of Dual Sexuality (jezik: engleski). Columbia University Press. str. 1–7. ISBN 978-0-231-52715-6. Pristupljeno 18. 9. 2020.

[7] Blackmon H, Ross L, Bachtrog D (januar 2017). "Sex Determination, Sex Chromosomes, and Karyotype Evolution in Insects". The Journal of Heredity. 108 (1): 78–93. doi:10.1093/jhered/esw047. ISSN 0022-1503. PMC 6281344. PMID 27543823.

[Hake-2008-8] Hake L, O'Connor C (2008). "Genetic Mechanisms of Sex Determination | Learn Science at Scitable". Nature Education. 1 (1): 25. Arhivirano s originala, 19. 8. 2017. Pristupljeno 13. 4. 2021.

[Moore-2020-9] Moore D, Robson JD, Trinci AP (2020). 21st Century guidebook to fungi (2 izd.). Cambridge University Press. str. 211–228. ISBN 978-1-108-74568-0.

[Kumar-2019-10] Kumar R, Meena M, Swapnil P (2019). "Anisogamy". u Vonk J, Shackelford T (ured.). Encyclopedia of Animal Cognition and Behavior. Cham: Springer International Publishing. str. 1–5. doi:10.1007/978-3-319-47829-6_340-1. ISBN 978-3-319-47829-6. Anisogamy can be defined as a mode of sexual reproduction in which fusing gametes, formed by participating parents, are dissimilar in size.

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Spol

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