Editing Diatom (section)

===Cell division===
Vegetative cells of diatoms are [[diploid]] (2N) and so [[meiosis]] can take place, producing male and female gametes which then fuse to form the [[zygote]]. The zygote sheds its silica theca and grows into a large sphere covered by an organic membrane, the auxospore. A new diatom cell of maximum size, the initial cell, forms within the auxospore thus beginning a new generation. Resting spores may also be formed as a response to unfavourable environmental conditions with germination occurring when conditions improve.<ref name="Horner2002" />

A defining characteristic of all diatoms is their restrictive and bipartite silica cell wall that causes them to progressively shrink during asexual cell division. At a critically small cell size and under certain conditions, [[auxosporulation]] restitutes cell size and prevents [[:Wiktionary:clonal|clonal]] death.<ref>Lewis, W. M., Jr. (1984). "The diatom sex clock and its evolutionary significance". ''The American Naturalist'', '''123'''(1): 73–80</ref><ref>Chepurnov VA, Mann DG, Sabbe K, Vyverman W. (2004). "Experimental studies on sexual reproduction in diatoms". In Jeon KW, ed. ''A Survey of Cell Biology''. International Review of Cytology '''237''': 91–154. London.</ref><ref>Drebes (1977) "Sexuality". In: Werner D, ed. ''The Biology of Diatoms'', Botanical Monographs '''13''' 250–283. Oxford: Blackwell Scientific Publications.</ref><ref>{{cite journal | title=Size reduction, reproductive strategy and the life cycle of a centric diatom | journal=Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences | publisher=The Royal Society | volume=336 | issue=1277 | date=1992-05-29 | issn=0962-8436 | doi=10.1098/rstb.1992.0056 | pages=191–213 | s2cid=86332060 | ref={{sfnref | The Royal Society}}}}</ref><ref>{{cite journal | last1=Koester | first1=Julie A. | last2=Brawley | first2=Susan H. | last3=Karp-Boss | first3=Lee | last4=Mann | first4=David G. | title=Sexual reproduction in the marine centric diatom Ditylum brightwellii (Bacillariophyta) | journal=European Journal of Phycology | publisher=Informa UK Limited | volume=42 | issue=4 | year=2007 | issn=0967-0262 | doi=10.1080/09670260701562100 | pages=351–366| s2cid=80737380 | doi-access=free | bibcode=2007EJPhy..42..351K }}</ref> The entire lifecycles of only a few diatoms have been described and rarely have sexual events been captured in the environment.<ref name=Moore2017 />