Editing Cambrian (section)

== Flora ==
The Cambrian flora was little different from the Ediacaran. The principal taxa were the marine macroalgae ''[[Fuxianospira]]'', ''[[Sinocylindra]]'', and ''[[Marpolia]]''. No calcareous macroalgae are known from the period.<ref>{{cite journal |last1=LoDuca |first1=S. T. |last2=Bykova |first2=N. |last3=Wu |first3=M. |last4=Xiao |first4=S. |last5=Zhao |first5=Y. |title=Seaweed morphology and ecology during the great animal diversification events of the early Paleozoic: A tale of two floras |journal=Geobiology |date=July 2017 |volume=15 |issue=4 |pages=588–616 |doi=10.1111/gbi.12244|pmid=28603844 |bibcode=2017Gbio...15..588L |doi-access=free }}</ref>

No [[land plant]] ([[embryophyte]]) fossils are known from the Cambrian. However, biofilms and microbial mats were well developed on Cambrian tidal flats and beaches 500 mya,{{sfn|Schieber|Bose|Eriksson|Banerjee|2007|pp=53-71}} and microbes forming microbial Earth [[ecosystem]]s, comparable with modern [[cryptobiotic soil|soil crust]] of desert regions, contributing to soil formation.<ref>{{cite journal | last1 = Retallack | first1 = G.J. | year = 2008 | title = Cambrian palaeosols and landscapes of South Australia | journal = Alcheringa | volume = 55 | issue = 8| pages = 1083–1106 | doi=10.1080/08120090802266568|bibcode = 2008AuJES..55.1083R | s2cid = 128961644 }}</ref><ref>{{cite web|url=http://phys.org/news/2013-07-greening-earth.html|title=Greening of the Earth pushed way back in time|website=Phys.org|date = 22 July 2013|publisher = University of Oregon}}</ref> Although molecular clock estimates suggest [[Embryophyta|terrestrial plants]] may have first emerged during the Middle or Late Cambrian, the consequent large-scale removal of the [[greenhouse gas]] CO<sub>2</sub> from the atmosphere through sequestration did not begin until the Ordovician.<ref>{{cite journal |last1=Donoghue |first1=Philip C.J. |last2=Harrison |first2=C. Jill |last3=Paps |first3=Jordi |last4=Schneider |first4=Harald |title=The evolutionary emergence of land plants |journal=Current Biology |date=October 2021 |volume=31 |issue=19 |pages=R1281–R1298 |doi=10.1016/j.cub.2021.07.038|pmid=34637740 |hdl=1983/662d176e-fcf4-40bf-aa8c-5694a86bd41d |s2cid=238588736 |doi-access=free |bibcode=2021CBio...31R1281D |hdl-access=free }}</ref>

[[Land plants]] may have emerged during the Cambrian, but the evidence for this is fragmentary and contested and the oldest unamibiguous evidence for land plants is from the following Ordovician.<ref>{{Cite journal |last1=Strother |first1=Paul K. |last2=Foster |first2=Clinton |date=2021-08-13 |title=A fossil record of land plant origins from charophyte algae |url=https://www.science.org/doi/10.1126/science.abj2927 |journal=Science |language=en |volume=373 |issue=6556 |pages=792–796 |doi=10.1126/science.abj2927 |pmid=34385396 |bibcode=2021Sci...373..792S |issn=0036-8075}}</ref> [[Molecular clock]] estimates have also led some authors to suggest that arthropods colonised land during the Cambrian, but again the earliest physical evidence of this is during the following Ordovician.<ref>{{Cite journal |last1=Zong |first1=Ruiwen |last2=Edgecombe |first2=Gregory D. |last3=Liu |first3=Bingcai |last4=Wang |first4=Yi |last5=Yin |first5=Jiayi |last6=Ma |first6=Juan |last7=Xu |first7=Honghe |date=March 2023 |editor-last=Cherns |editor-first=Lesley |title=Silurian freshwater arthropod from northwest China |url=https://onlinelibrary.wiley.com/doi/10.1002/spp2.1488 |journal=Papers in Palaeontology |language=en |volume=9 |issue=2 |doi=10.1002/spp2.1488 |bibcode=2023PPal....9E1488Z |issn=2056-2799}}</ref>