Editing Sex (section)

===Environmental===
{{main|Environmental sex determination}}

For many species, sex is not determined by inherited traits, but instead by environmental factors such as temperature experienced during development or later in life.<ref>{{cite journal | vauthors = Janzen FJ, Phillips PC | title = Exploring the evolution of environmental sex determination, especially in reptiles | journal = Journal of Evolutionary Biology | volume = 19 | issue = 6 | pages = 1775–1784 | date = November 2006 | pmid = 17040374 | doi = 10.1111/j.1420-9101.2006.01138.x }}</ref>

In the [[fern]] ''[[Ceratopteris]]'' and other [[Glossary of botanical terms#homospory|homosporous]] fern species, the default sex is hermaphrodite, but individuals which grow in soil that has previously supported hermaphrodites are influenced by the [[pheromone]] [[antheridiogen]] to develop as male.<ref name="Tanurdzic-2004" /> The [[bonelliidae|bonelliidae larvae]] can only develop as males when they encounter a female.<ref name="Bachtrog-2014" />

==== Sequential hermaphroditism ====
[[File:Ocellaris clownfish.JPG|thumb|[[Clownfish]]es are initially male; the largest fish in a group becomes female.]]

Some species can change sex over the course of their lifespan, a phenomenon called [[sequential hermaphroditism]].<ref name="Fusco-2019">{{cite book| vauthors = Fusco G, Minelli A |author-link2=Alessandro Minelli (biologist) |url={{GBurl|id=AKGsDwAAQBAJ|q=sequential+hermaphroditism+in+plants}}|title=The Biology of Reproduction |date=2019|publisher=Cambridge University Press|isbn=978-1-108-49985-9|pages=124|language=en}}</ref> 

[[Teleost|Teleost fishes]] are the only vertebrate [[Lineage (evolution)|lineage]] where sequential hermaphroditism occurs. In [[clownfish]], smaller fish are male, and the dominant and largest fish in a group becomes female; when a dominant female is absent, then her partner changes sex from male to female. In many [[wrasse]]s the opposite is true:  the fish are initially female and become male when they reach a certain size.<ref>{{cite journal|author-link4=Neil Gemmell|vauthors=Todd EV, Liu H, Muncaster S, Gemmell NJ|date=2016|title=Bending Genders: The Biology of Natural Sex Change in Fish|journal=Sexual Development|language=english|volume=10|issue=5–6|pages=223–2241|doi=10.1159/000449297|pmid=27820936|s2cid=41652893|doi-access=free|hdl=10536/DRO/DU:30153787|hdl-access=free}}</ref> 

Sequential hermaphroditism also occurs in plants such as ''[[Arisaema triphyllum]]''.

==== Temperature-dependent sex determination ====
[[File:Crocoparc Naissance des bébés.jpg|alt=pile of eggs in the sand, with a newly hatched crocodile looking over the top|thumb|Crocodiles do not have [[sex chromosomes]].<ref>{{cite journal | vauthors = González EJ, Martínez-López M, Morales-Garduza MA, García-Morales R, Charruau P, Gallardo-Cruz JA | title = The sex-determination pattern in crocodilians: A systematic review of three decades of research | journal = The Journal of Animal Ecology | volume = 88 | issue = 9 | pages = 1417–1427 | date = September 2019 | pmid = 31286510 | doi = 10.1111/1365-2656.13037 | bibcode = 2019JAnEc..88.1417G }}</ref>  Instead, whether these eggs will produce male or female crocodiles depends on the temperature of the eggs.]]

Many [[reptile]]s, including all [[crocodile]]s and most [[turtles]], have [[temperature-dependent sex determination]]. In these species, the temperature experienced by the embryos during their development determines their sex.<ref name="Bachtrog-2014" /> 

In some turtles, for example, males are produced at lower temperatures than females; but ''[[Alligator snapping turtle|Macroclemys]]'' females are produced at temperatures lower than 22&nbsp;°C or above 28&nbsp;°C, while males are produced in between those temperatures.<ref>{{cite journal|author-link=Scott F. Gilbert|vauthors=Gilbert SF|date=2000|title=Environmental Sex Determination|url=https://www.ncbi.nlm.nih.gov/books/NBK9989/|journal=Developmental Biology. 6th Edition|language=en|access-date=19 May 2021|archive-date=12 June 2021|archive-url=https://web.archive.org/web/20210612123300/https://www.ncbi.nlm.nih.gov/books/NBK9989/|url-status=live}}</ref>

====Haplodiploidy====
Certain insects, such as [[honey bee]]s and [[ant]]s, use a [[Haplodiploidy|haplodiploid sex-determination system]].<ref>{{cite journal|author-link=Brian Charlesworth|vauthors=Charlesworth B|date=August 2003|title=Sex determination in the honeybee|journal=Cell|volume=114|issue=4|pages=397–398|doi=10.1016/S0092-8674(03)00610-X|pmid=12941267|doi-access=free}}</ref> Diploid bees and ants are generally female, and haploid individuals (which develop from unfertilized eggs) are male. This sex-determination system results in highly biased [[sex ratio]]s, as the sex of offspring is determined by fertilization ([[arrhenotoky]] or [[pseudo-arrhenotoky]] resulting in males) rather than the assortment of chromosomes during meiosis.<ref>{{cite journal |vauthors=de la Filia A, Bain S, Ross L |title=Haplodiploidy and the reproductive ecology of Arthropods |journal=Current Opinion in Insect Science |date=June 2015 |volume=9 |pages=36–43 |doi=10.1016/j.cois.2015.04.018 |pmid=32846706 |bibcode=2015COIS....9...36D |url=https://www.pure.ed.ac.uk/ws/files/20137629/1_s2.0_S221457451500084X_main.pdf |hdl=20.500.11820/b540f12f-846d-4a5a-9120-7b2c45615be6 |s2cid=83988416 |hdl-access=free |access-date=25 June 2021 |archive-date=25 June 2021 |archive-url=https://web.archive.org/web/20210625230005/https://www.pure.ed.ac.uk/ws/files/20137629/1_s2.0_S221457451500084X_main.pdf |url-status=live }}</ref>