Editing Volvox (section)

== Evolution ==
''Volvox'' is [[polyphyletic]]. The section containing the type species, ''Volvox'' sect. ''Volvox'', is [[sister group|sister]] to the rest of the family. Other members of ''Volvox'' are dispersed within three clades, all nested within ''Eudorina''.<ref name=Lindsey2024>{{Cite journal |last1=Lindsey |first1=Charles Ross |last2=Knoll |first2=Andrew H. |last3=Herron |first3=Matthew D. |last4=Rosenzweig |first4=Frank |date=2024-04-10 |title=Fossil-calibrated molecular clock data enable reconstruction of steps leading to differentiated multicellularity and anisogamy in the Volvocine algae |journal=BMC Biology |volume=22 |issue=1 |pages=79 |doi=10.1186/s12915-024-01878-1 |issn=1741-7007 |pmid=38600528 |doi-access=free|pmc=11007952 |bibcode=2024BMCB...22...79L }}</ref>

Ancestors of ''Volvox'' transitioned from single cells that initially resembled ''[[Chlamydomonas]]'' to form multicellular colonies at least {{Ma|200}}, during the [[Triassic]] [[Geologic time scale|period]].<ref name="daily" /><ref name="Herron2009">{{cite journal |last1=Herron |first1=MD |last2=Hackett |first2=JD |last3=Aylward |first3=FO |last4=Michod |first4=RE |date=2009 |title=Triassic origin and early radiation of multicellular volvocine algae |journal=Proceedings of the National Academy of Sciences, USA |doi=10.1073/pnas.0811205106 |pmid=19223580 |volume=106 |issue=9 |pages=3254–3258 |bibcode=2009PNAS..106.3254H |pmc=2651347|doi-access=free }}</ref>
Genera intermediate in morphology, such as ''Gonium'', contain 16 ''Chlamydomonas''-like cells and are thought to represent intermediate stages in evolution. An estimate using [[DNA sequence]]s from about 45 different species of volvocine green algae, including ''Volvox'', suggests that the transition from single cells to undifferentiated multicellular colonies took about 35 million years.<ref name="daily" /><ref name="Herron2009" />