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Expanded on evidence for oxygenation as GOBE's cause and wrote about the Furongian Gap.
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The dispersed positions of the continents, high level of tectonic/volcanic activity, warm climate, and high CO<sub>2</sub> levels would have created a large, nutrient-rich [[Ecology|ecospace]], favoring diversification.<ref name=Servais2008/> There seems to be an association between [[orogeny]] and the evolutionary radiation,<ref>{{Cite journal |last1=Miller |first1=Arnold I. |last2=Mao |first2=Shuguang |date=1995-04-01 |title=Association of orogenic activity with the Ordovician radiation of marine life |url=https://doi.org/10.1130/0091-7613(1995)0232.3.CO;2 |journal=[[Geology (journal)|Geology]] |volume=23 |issue=4 |pages=305–308 |doi=10.1130/0091-7613(1995)023<0305:AOOAWT>2.3.CO;2 |pmid=11539503 |issn=0091-7613}}</ref> with the [[Taconic orogeny]] in particular being singled out as a driver of the GOBE by enabling greater erosion of nutrients such as iron and phosphorus and their delivery to the oceans around Laurentia.<ref name="KozikEtAl2019" /> In addition, the changing geography led to a more diverse landscape, with more different and isolated environments; this no doubt facilitated the emergence of bioprovinciality, and [[speciation]] by isolation of populations.<ref name=Munnecke2010/>
The dispersed positions of the continents, high level of tectonic/volcanic activity, warm climate, and high CO<sub>2</sub> levels would have created a large, nutrient-rich [[Ecology|ecospace]], favoring diversification.<ref name=Servais2008/> There seems to be an association between [[orogeny]] and the evolutionary radiation,<ref>{{Cite journal |last1=Miller |first1=Arnold I. |last2=Mao |first2=Shuguang |date=1995-04-01 |title=Association of orogenic activity with the Ordovician radiation of marine life |url=https://doi.org/10.1130/0091-7613(1995)0232.3.CO;2 |journal=[[Geology (journal)|Geology]] |volume=23 |issue=4 |pages=305–308 |doi=10.1130/0091-7613(1995)023<0305:AOOAWT>2.3.CO;2 |pmid=11539503 |issn=0091-7613}}</ref> with the [[Taconic orogeny]] in particular being singled out as a driver of the GOBE by enabling greater erosion of nutrients such as iron and phosphorus and their delivery to the oceans around Laurentia.<ref name="KozikEtAl2019" /> In addition, the changing geography led to a more diverse landscape, with more different and isolated environments; this no doubt facilitated the emergence of bioprovinciality, and [[speciation]] by isolation of populations.<ref name=Munnecke2010/>


On the other hand, global cooling has also been offered as a cause of the radiation,<ref>{{cite journal |last1=Cocks |first1=L. Robin M. |last2=Torsvik |first2=Trond H. |date=December 2021 |title=Ordovician palaeogeography and climate change |url=https://www.sciencedirect.com/science/article/pii/S1342937X20302756 |journal=[[Gondwana Research]] |volume=100 |pages=53-72 |doi=10.1016/j.gr.2020.09.008 |access-date=26 May 2023}}</ref><ref name="Trotter et al., 2008">{{Cite journal | year = 2008 | title = Did cooling oceans trigger Ordovician biodiversification? Evidence from conodont thermometry | journal = [[Science (journal)|Science]] | volume = 321 | issue = 5888 | pages = 550–4 | doi = 10.1126/science.1155814 | pmid=18653889 | last1 = Trotter | first1 = JA | last2 = Williams | first2 = IS | last3 = Barnes | first3 = CR | last4 = Lécuyer | first4 = C | last5 = Nicoll | first5 = RS| bibcode = 2008Sci...321..550T| s2cid = 28224399 }}</ref><ref>{{Cite journal |last1=Goldberg |first1=Samuel L. |last2=Present |first2=Theodore M. |last3=Finnegan |first3=Seth |last4=Bergmann |first4=Kristin D. |date=2021-02-09 |title=A high-resolution record of early Paleozoic climate |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=118 |issue=6 |pages=e2013083118 |doi=10.1073/pnas.2013083118 |pmid=33526667 |issn=0027-8424 |pmc=8017688 |doi-access=free }}</ref> with an uptick in [[fossil]] diversity correlating with the increasing abundance of cool-water [[carbonate rocks|carbonates]] over the course of this time interval.<ref>{{cite journal |last1=Dronov |first1=Andrei |date=1 November 2013 |title=Late Ordovician cooling event: Evidence from the Siberian Craton |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018213002745 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=389 |issue= |pages=87–95 |doi=10.1016/j.palaeo.2013.05.032 |access-date=20 October 2022}}</ref>
On the other hand, global cooling has also been offered as a cause of the radiation,<ref>{{cite journal |last1=Cocks |first1=L. Robin M. |last2=Torsvik |first2=Trond H. |date=December 2021 |title=Ordovician palaeogeography and climate change |url=https://www.sciencedirect.com/science/article/pii/S1342937X20302756 |journal=[[Gondwana Research]] |volume=100 |pages=53-72 |doi=10.1016/j.gr.2020.09.008 |access-date=26 May 2023}}</ref><ref name="Trotter et al., 2008">{{Cite journal | year = 2008 | title = Did cooling oceans trigger Ordovician biodiversification? Evidence from conodont thermometry | journal = [[Science (journal)|Science]] | volume = 321 | issue = 5888 | pages = 550–4 | doi = 10.1126/science.1155814 | pmid=18653889 | last1 = Trotter | first1 = JA | last2 = Williams | first2 = IS | last3 = Barnes | first3 = CR | last4 = Lécuyer | first4 = C | last5 = Nicoll | first5 = RS| bibcode = 2008Sci...321..550T| s2cid = 28224399 }}</ref> with an uptick in [[fossil]] diversity correlating with the increasing abundance of cool-water [[carbonate rocks|carbonates]] over the course of this time interval.<ref>{{cite journal |last1=Dronov |first1=Andrei |date=1 November 2013 |title=Late Ordovician cooling event: Evidence from the Siberian Craton |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018213002745 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=389 |issue= |pages=87–95 |doi=10.1016/j.palaeo.2013.05.032 |access-date=20 October 2022}}</ref> Long-term biodiversity trends show a positive correlation between cooling and biodiversity during GOBE.<ref>{{Cite journal |last1=Goldberg |first1=Samuel L. |last2=Present |first2=Theodore M. |last3=Finnegan |first3=Seth |last4=Bergmann |first4=Kristin D. |date=2021-02-09 |title=A high-resolution record of early Paleozoic climate |journal=[[Proceedings of the National Academy of Sciences of the United States of America]] |language=en |volume=118 |issue=6 |pages=e2013083118 |doi=10.1073/pnas.2013083118 |pmid=33526667 |issn=0027-8424 |pmc=8017688 |doi-access=free }}</ref><ref>{{cite journal |last1=Fan |first1=Jun-xuan |last2=Shen |first2=Shu-zhong |last3=Erwin |first3=Douglas H. |last4=Sadler |first4=Peter M. |last5=MacLeod |first5=Norman |last6=Cheng |first6=Qiu-ming |last7=Ho |first7=Xu-dong |last8=Yang |first8=Jiao |last9=Wang |first9=Xiang-dong |last10=Wang |first10=Yue |last11=Zhang |first11=Hua |last12=Chen |first12=Xu |last13=Li |first13=Guo-xiang |last14=Zhang |first14=Yi-Chun |last15=Shi |first15=Yu-kun |last16=Yuan |first16=Dong-xun |last17=Chen |first17=Qing |last18=Zhang |first18=Lin-na |last19=Li |first19=Chao |last20=Zhao |first20=Ying-ying |date=17 January 2020 |title=A high-resolution summary of Cambrian to Early Triassic marine invertebrate biodiversity |url=https://www.science.org/doi/10.1126/science.aax4953 |journal=[[Science (journal)|Science]] |volume=367 |issue=6475 |pages=272-277 |doi=10.1126/science.aax4953 |access-date=5 July 2023}}</ref>


[[Thallium]] isotope shifts show an expansion of oxic waters throughout deep water and shallow shelf environments during the latest Cambrian and earliest Ordovician coeval with increasing burrowing depth and complexity observed among ichnofossils and increasing morphological complexity among body fossils. Thus, heightened oxygen availability may have been a key trigger for GOBE.<ref name="KozikEtAl2023">{{cite journal |last1=Kozik |first1=Nevin P. |last2=Young |first2=Seth A. |last3=Lindskog |first3=Anders |last4=Ahlberg |first4=Per |last5=Owens |first5=Jeremy D. |date=26 January 2023 |title=Protracted oxygenation across the Cambrian–Ordovician transition: A key initiator of the Great Ordovician Biodiversification Event? |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/gbi.12545 |journal=[[Geobiology (journal)|Geobiology]] |volume=21 |issue=3 |pages=323-340 |doi=10.1111/gbi.12545 |access-date=21 April 2023}}</ref> After the [[Steptoean positive carbon isotope excursion|SPICE event]] about 500 million years ago, the extinction in the ocean would have opened up new niches for photosynthetic plankton, who would absorb CO<sub>2</sub> from the atmosphere and release large amount of oxygen. More oxygen and a more diversified photosynthetic plankton as the bottom of the food chain, would have affected the diversity of higher marine organisms and their ecosystems.<ref>[http://www.dailygalaxy.com/my_weblog/2011/02/mystery-of-earths-first-breathable-atmosphere-solved.html Solved: Mystery of Earth's First Breathable Atmosphere]</ref>
[[Thallium]] isotope shifts show an expansion of oxic waters throughout deep water and shallow shelf environments during the latest Cambrian and earliest Ordovician coeval with increasing burrowing depth and complexity observed among ichnofossils and increasing morphological complexity among body fossils. Thus, heightened oxygen availability may have been a key trigger for GOBE.<ref name="KozikEtAl2023">{{cite journal |last1=Kozik |first1=Nevin P. |last2=Young |first2=Seth A. |last3=Lindskog |first3=Anders |last4=Ahlberg |first4=Per |last5=Owens |first5=Jeremy D. |date=26 January 2023 |title=Protracted oxygenation across the Cambrian–Ordovician transition: A key initiator of the Great Ordovician Biodiversification Event? |url=https://onlinelibrary.wiley.com/doi/abs/10.1111/gbi.12545 |journal=[[Geobiology (journal)|Geobiology]] |volume=21 |issue=3 |pages=323-340 |doi=10.1111/gbi.12545 |access-date=21 April 2023}}</ref> After the [[Steptoean positive carbon isotope excursion|SPICE event]] about 500 million years ago, the extinction in the ocean would have opened up new niches for photosynthetic plankton, who would absorb CO<sub>2</sub> from the atmosphere and release large amount of oxygen. More oxygen and a more diversified photosynthetic plankton as the bottom of the food chain, would have affected the diversity of higher marine organisms and their ecosystems.<ref>[http://www.dailygalaxy.com/my_weblog/2011/02/mystery-of-earths-first-breathable-atmosphere-solved.html Solved: Mystery of Earth's First Breathable Atmosphere]</ref>
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If the Cambrian Explosion is thought of as producing the modern [[Phylum|phyla]],<ref name=Landing2010>All mineralized phyla were present by the end of the Cambrian; see {{Cite journal| doi = 10.1130/G30870.1| title = Cambrian origin of all skeletalized metazoan phyla--Discovery of Earth's oldest bryozoans (Upper Cambrian, southern Mexico)| year = 2010| last1 = Landing | first1 = E.| last2 = English | first2 = A.| last3 = Keppie | first3 = J. D.| journal = [[Geology (journal)|Geology]]| volume = 38| issue = 6| pages = 547–550| bibcode = 2010Geo....38..547L}}</ref> the GOBE can be considered as the "filling out" of these phyla with the modern (and many extinct) classes and lower-level taxa.<ref name=Servais2010/> The GOBE is considered to be one of the most potent speciation events of the Phanerozoic era increasing global diversity severalfold.<ref name=":0">{{Cite journal |last=Stigall |display-authors=etal |first=A.L |date=December 2016 |title=Biotic immigration events, speciation, and the accumulation of biodiversity in the fossil record |journal=[[Global and Planetary Change]] |volume=148 |pages=242–257 |doi=10.1016/j.gloplacha.2016.12.008 |bibcode=2017GPC...148..242S}}</ref>
If the Cambrian Explosion is thought of as producing the modern [[Phylum|phyla]],<ref name=Landing2010>All mineralized phyla were present by the end of the Cambrian; see {{Cite journal| doi = 10.1130/G30870.1| title = Cambrian origin of all skeletalized metazoan phyla--Discovery of Earth's oldest bryozoans (Upper Cambrian, southern Mexico)| year = 2010| last1 = Landing | first1 = E.| last2 = English | first2 = A.| last3 = Keppie | first3 = J. D.| journal = [[Geology (journal)|Geology]]| volume = 38| issue = 6| pages = 547–550| bibcode = 2010Geo....38..547L}}</ref> the GOBE can be considered as the "filling out" of these phyla with the modern (and many extinct) classes and lower-level taxa.<ref name=Servais2010/> The GOBE is considered to be one of the most potent speciation events of the Phanerozoic era increasing global diversity severalfold.<ref name=":0">{{Cite journal |last=Stigall |display-authors=etal |first=A.L |date=December 2016 |title=Biotic immigration events, speciation, and the accumulation of biodiversity in the fossil record |journal=[[Global and Planetary Change]] |volume=148 |pages=242–257 |doi=10.1016/j.gloplacha.2016.12.008 |bibcode=2017GPC...148..242S}}</ref>


Notable taxonomic diversity explosions during this period include that of articulated [[Brachiopod|brachiopods]], [[Gastropoda|gastropods]] and [[Bivalvia|bivalves]].<ref name=":0" />
Notable taxonomic diversity explosions during this period include that of articulated [[Brachiopod|brachiopods]], [[Gastropoda|gastropods]], and [[Bivalvia|bivalves]].<ref name=":0" />


Taxonomic diversity increased manifold; the total number of marine [[Order (biology)|orders]] doubled, and [[Family (biology)|families]] tripled.<ref name="Droser2003">{{Cite journal| doi = 10.1093/icb/43.1.178| title = The Ordovician Radiation: A Follow-up to the Cambrian Explosion?| year = 2003| last1 = Droser | first1 = M. L.| journal = [[Integrative and Comparative Biology]]| volume = 43| pages = 178–184| last2 = Finnegan | first2 = S.| issue = 1| pmid=21680422| doi-access = free}}</ref>
Taxonomic diversity increased manifold; the total number of marine [[Order (biology)|orders]] doubled, and [[Family (biology)|families]] tripled.<ref name="Droser2003">{{Cite journal| doi = 10.1093/icb/43.1.178| title = The Ordovician Radiation: A Follow-up to the Cambrian Explosion?| year = 2003| last1 = Droser | first1 = M. L.| journal = [[Integrative and Comparative Biology]]| volume = 43| pages = 178–184| last2 = Finnegan | first2 = S.| issue = 1| pmid=21680422| doi-access = free}}</ref>
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The global fauna that emerged during the GOBE went on to be remarkably stable until the catastrophic [[end-Permian extinction]] and the ensuing [[Mesozoic Marine Revolution]].<ref name="Munnecke2010" />
The global fauna that emerged during the GOBE went on to be remarkably stable until the catastrophic [[end-Permian extinction]] and the ensuing [[Mesozoic Marine Revolution]].<ref name="Munnecke2010" />


The [[acritarch]] record (the majority of acritarchs were probably marine algae)<ref name=Servais2010/> displays the Ordovician radiation beautifully; both diversity and disparity peaked in the middle Ordovician.<ref name=Servais2008>{{Cite journal | doi = 10.1111/j.1502-3931.2008.00115.x | title = The Ordovician Biodiversification: revolution in the oceanic trophic chain | year = 2008 | last1 = Servais | first1 = T. | last2 = Lehnert | first2 = O. | last3 = Li | first3 = J. | last4 = Mullins | first4 = G. L. | last5 = Munnecke | first5 = A. | last6 = Nützel | first6 = A. | last7 = Vecoli | first7 = M. | journal = [[Lethaia]] | volume = 41 | issue = 2 | pages = 99–109}}</ref> The warm waters and high sea level (which had been rising steadily since the early Cambrian) permitted large numbers of [[phytoplankton]] to prosper; the accompanying diversification of the phytoplankton may have caused an accompanying radiation of [[zooplankton]] and suspension feeders.<ref name=Servais2008/>
The [[acritarch]] record (the majority of acritarchs were probably marine algae)<ref name=Servais2010/> displays the Ordovician radiation beautifully; both diversity and disparity peaked in the middle Ordovician. The warm waters and high sea level (which had been rising steadily since the early Cambrian) permitted large numbers of [[phytoplankton]] to prosper; the accompanying diversification of the phytoplankton may have caused an accompanying radiation of [[zooplankton]] and suspension feeders.<ref name=Servais2008>{{Cite journal | doi = 10.1111/j.1502-3931.2008.00115.x | title = The Ordovician Biodiversification: revolution in the oceanic trophic chain | year = 2008 | last1 = Servais | first1 = T. | last2 = Lehnert | first2 = O. | last3 = Li | first3 = J. | last4 = Mullins | first4 = G. L. | last5 = Munnecke | first5 = A. | last6 = Nützel | first6 = A. | last7 = Vecoli | first7 = M. | journal = [[Lethaia]] | volume = 41 | issue = 2 | pages = 99–109}}</ref>


The planktonic realm was invaded as never before, with several invertebrate lineages colonising the open waters and initiating new food chains at the end of the Cambrian into the early Ordovician.<ref>{{cite journal | year = 2009 | title = The Origin and Initial Rise of Pelagic Cephalopods in the Ordovician | journal = [[PLOS ONE]] | volume = 4 | issue = 9 | pages = e7262 | editor1-first = Matthew | doi = 10.1371/journal.pone.0007262 | editor1-last = Kosnik | pmid = 19789709 | pmc = 2749442 | last1 = Kröger | first = B. R. | last2 = Servais | first2 = T. | last3 = Zhang | first3 = Y. | last4 = Kosnik | first4 = M. | bibcode = 2009PLoSO...4.7262K | doi-access = free }}</ref>
The planktonic realm was invaded as never before, with several invertebrate lineages colonising the open waters and initiating new food chains at the end of the Cambrian into the early Ordovician.<ref name="RiseOfPelagicCephalopods">{{cite journal | year = 2009 | title = The Origin and Initial Rise of Pelagic Cephalopods in the Ordovician | journal = [[PLOS ONE]] | volume = 4 | issue = 9 | pages = e7262 | editor1-first = Matthew | doi = 10.1371/journal.pone.0007262 | editor1-last = Kosnik | pmid = 19789709 | pmc = 2749442 | last1 = Kröger | first = B. R. | last2 = Servais | first2 = T. | last3 = Zhang | first3 = Y. | last4 = Kosnik | first4 = M. | bibcode = 2009PLoSO...4.7262K | doi-access = free }}</ref> Among the newcomers colonising the planktonic realm were trilobites<ref>{{cite journal |last1=Esteve |first1=Jorge |last2=López-Pachón |first2=Matheo |date=1 September 2023 |title=Swimming and feeding in the Ordovician trilobite Microparia speciosa shed light on the early history of nektonic life habits |url=https://www.sciencedirect.com/science/article/pii/S0031018223003097 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=625 |doi=10.1016/j.palaeo.2023.111691 |access-date=5 July 2023}}</ref> and cephalopods.<ref name="RiseOfPelagicCephalopods" />


[[Beta diversity]] was the most important component of biodiversity increase from the Furongian to the Tremadocian. From the Floian onward, [[alpha diversity]] dethroned beta diversity as the greater contributor to regional diversity patterns.<ref>{{cite journal |last1=Serra |first1=Fernanda |last2=Balseiro |first2=Diego |last3=Waisfeld |first3=Beatriz G. |date=1 April 2023 |title=Morphospace trends underlying a global turnover: Ecological dynamics of trilobite assemblages at the onset of the Ordovician Radiation |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018223000664 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=615 |doi=10.1016/j.palaeo.2023.111448 |access-date=21 April 2023}}</ref>
[[Beta diversity]] was the most important component of biodiversity increase from the Furongian to the Tremadocian. From the Floian onward, [[alpha diversity]] dethroned beta diversity as the greater contributor to regional diversity patterns.<ref>{{cite journal |last1=Serra |first1=Fernanda |last2=Balseiro |first2=Diego |last3=Waisfeld |first3=Beatriz G. |date=1 April 2023 |title=Morphospace trends underlying a global turnover: Ecological dynamics of trilobite assemblages at the onset of the Ordovician Radiation |url=https://www.sciencedirect.com/science/article/abs/pii/S0031018223000664 |journal=[[Palaeogeography, Palaeoclimatology, Palaeoecology]] |volume=615 |doi=10.1016/j.palaeo.2023.111448 |access-date=21 April 2023}}</ref>

Revision as of 04:28, 6 July 2023

The Great Ordovician Biodiversification Event (GOBE), was an evolutionary radiation of animal life throughout[1] the Ordovician period, 40 million years after the Cambrian explosion,[2] whereby the distinctive Cambrian fauna fizzled out to be replaced with a Paleozoic fauna rich in suspension feeder and pelagic animals.[3]

It followed a series of Cambrian–Ordovician extinction events, and the resulting fauna went on to dominate the Palaeozoic relatively unchanged.[4] Marine diversity increased to levels typical of the Palaeozoic,[5] and morphological disparity was similar to today's.[6][7] The diversity increase was neither global nor instantaneous; it happened at different times in different places.[4] Consequently, there is unlikely to be a simple or straightforward explanation for the event; the interplay of many geological and ecological factors likely produced the diversification.[1]

Causes

Possible line of meteors (on the modern globe) associated with the Middle Ordovician meteor event 467.5±0.28 million years ago. Although this is suggestive of a single large meteorite shower, the exact alignment of continental plates 470 million years ago is unknown and the exact timing of meteors is also unknown.

Possible causes include an increase in marine oxygen content,[8] changes in palaeogeography or tectonic activity,[9] a modified nutrient supply,[10] or global cooling.[9]

The dispersed positions of the continents, high level of tectonic/volcanic activity, warm climate, and high CO2 levels would have created a large, nutrient-rich ecospace, favoring diversification.[2] There seems to be an association between orogeny and the evolutionary radiation,[11] with the Taconic orogeny in particular being singled out as a driver of the GOBE by enabling greater erosion of nutrients such as iron and phosphorus and their delivery to the oceans around Laurentia.[9] In addition, the changing geography led to a more diverse landscape, with more different and isolated environments; this no doubt facilitated the emergence of bioprovinciality, and speciation by isolation of populations.[1]

On the other hand, global cooling has also been offered as a cause of the radiation,[12][13] with an uptick in fossil diversity correlating with the increasing abundance of cool-water carbonates over the course of this time interval.[14] Long-term biodiversity trends show a positive correlation between cooling and biodiversity during GOBE.[15][16]

Thallium isotope shifts show an expansion of oxic waters throughout deep water and shallow shelf environments during the latest Cambrian and earliest Ordovician coeval with increasing burrowing depth and complexity observed among ichnofossils and increasing morphological complexity among body fossils. Thus, heightened oxygen availability may have been a key trigger for GOBE.[8] After the SPICE event about 500 million years ago, the extinction in the ocean would have opened up new niches for photosynthetic plankton, who would absorb CO2 from the atmosphere and release large amount of oxygen. More oxygen and a more diversified photosynthetic plankton as the bottom of the food chain, would have affected the diversity of higher marine organisms and their ecosystems.[17]

Another alternative is that the breakup of an asteroid led to the Earth being consistently pummelled by meteorites,[3] although the proposed Ordovician meteor event happened at 467.5±0.28 million years ago.[18][19] Another effect of a collision between two asteroids, possibly beyond the orbit of Mars, is a reduction in sunlight reaching the Earth's surface due to the vast dust clouds created. Evidence for this geological event comes from the relative abundance of the isotope helium-3, found in ocean sediments laid down at the time of the biodiversification event. The most likely cause of the production of high levels of helium-3 is the bombardment of lithium by cosmic rays, something which could only have happened to material which travelled through space.[20] The volcanic activity that created the Flat Landing Brook Formation in New Brunswick, Canada may have caused rapid climatic cooling and biodiversification.[21]

The above triggers would have been amplified by ecological escalation, whereby any new species would co-evolve with others, creating new niches through niche partitioning, trophic layering, or by providing a new habitat.[clarification needed][10] As with the Cambrian Explosion, it is likely that environmental changes drove the diversification of plankton, which permitted an increase in diversity and abundance of plankton-feeding lifeforms, including suspension feeders on the sea floor, and nektonic organisms in the water column.[3]

Effects

Atrypid brachiopods (Zygospira modesta) preserved in their original positions on a trepostome bryozoan; Cincinnatian (Upper Ordovician) of southeastern Indiana.

If the Cambrian Explosion is thought of as producing the modern phyla,[22] the GOBE can be considered as the "filling out" of these phyla with the modern (and many extinct) classes and lower-level taxa.[3] The GOBE is considered to be one of the most potent speciation events of the Phanerozoic era increasing global diversity severalfold.[23]

Notable taxonomic diversity explosions during this period include that of articulated brachiopods, gastropods, and bivalves.[23]

Taxonomic diversity increased manifold; the total number of marine orders doubled, and families tripled.[4] In addition to a diversification, the event also marked an increase in the complexity of both organisms and food webs.[1] Taxa began to have localized ranges, with different faunas at different parts of the globe.[1] Communities in reefs and deeper water began to take on a character of their own, becoming more clearly distinct from other marine ecosystems.[1] And as ecosystems became more diverse, with more species being squeezed into the food web, a more complex tangle of ecological interactions resulted, promoting strategies such as ecological tiering.[1] The global fauna that emerged during the GOBE went on to be remarkably stable until the catastrophic end-Permian extinction and the ensuing Mesozoic Marine Revolution.[1]

The acritarch record (the majority of acritarchs were probably marine algae)[3] displays the Ordovician radiation beautifully; both diversity and disparity peaked in the middle Ordovician. The warm waters and high sea level (which had been rising steadily since the early Cambrian) permitted large numbers of phytoplankton to prosper; the accompanying diversification of the phytoplankton may have caused an accompanying radiation of zooplankton and suspension feeders.[2]

The planktonic realm was invaded as never before, with several invertebrate lineages colonising the open waters and initiating new food chains at the end of the Cambrian into the early Ordovician.[24] Among the newcomers colonising the planktonic realm were trilobites[25] and cephalopods.[24]

Beta diversity was the most important component of biodiversity increase from the Furongian to the Tremadocian. From the Floian onward, alpha diversity dethroned beta diversity as the greater contributor to regional diversity patterns.[26]

Relationship to the Cambrian Explosion

Recent work has suggested that the Cambrian Explosion and GOBE, rather than being two distinct events, represented one continual evolutionary radiation of marine life occurring over the entire Early Palaeozoic.[27] An analysis of the Paleobiology Database (PBDB) and Geobiodiversity Database (GBDB) found no statistical basis for separating the two radiations into discrete events.[28]

A proposed biodiversity gap known as the Furongian Gap is thought by some researchers to have existed between the Cambrian Explosion and GOBE existed during the Furongian epoch, the final epoch of the Cambrian. However, whether this gap is real or an artefact of an incomplete fossil record is controversial.[29] Analysis of the Guole Konservat-Lagerstätte and other sites in South China suggests the Furongian Gap did not exist, instead portraying this interval as one of rapid biotic turnovers.[30]

See also

References

  1. ^ a b c d e f g h Munnecke, A.; Calner, M.; Harper, D. A. T.; Servais, T. (2010). "Ordovician and Silurian sea-water chemistry, sea level, and climate: A synopsis". Palaeogeography, Palaeoclimatology, Palaeoecology. 296 (3–4): 389–413. Bibcode:2010PPP...296..389M. doi:10.1016/j.palaeo.2010.08.001.
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  3. ^ a b c d e Servais, T.; Owen, A. W.; Harper, D. A. T.; Kröger, B. R.; Munnecke, A. (2010). "The Great Ordovician Biodiversification Event (GOBE): the palaeoecological dimension". Palaeogeography, Palaeoclimatology, Palaeoecology. 294 (3–4): 99–119. doi:10.1016/j.palaeo.2010.05.031.
  4. ^ a b c Droser, M. L.; Finnegan, S. (2003). "The Ordovician Radiation: A Follow-up to the Cambrian Explosion?". Integrative and Comparative Biology. 43 (1): 178–184. doi:10.1093/icb/43.1.178. PMID 21680422.
  5. ^ Marshall, C. R. (2006). "Explaining the Cambrian "explosion" of Animals". Annual Review of Earth and Planetary Sciences. 34: 355–384. Bibcode:2006AREPS..34..355M. doi:10.1146/annurev.earth.33.031504.103001.
  6. ^ Bush, A. M.; Bambach, R. K.; Daley, G. M. (2007). "Changes in theoretical ecospace utilization in marine fossil assemblages between the mid-Paleozoic and late Cenozoic". Paleobiology. 33: 76–97. doi:10.1666/06013.1. S2CID 140675365.
  7. ^ Bambach, R. K.; Bush, A. M.; Erwin, D. H. (2007). "Autecology and the Filling of Ecospace: Key Metazoan Radiations". Palaeontology. 50: 1–22. doi:10.1111/j.1475-4983.2006.00611.x.
  8. ^ a b Kozik, Nevin P.; Young, Seth A.; Lindskog, Anders; Ahlberg, Per; Owens, Jeremy D. (26 January 2023). "Protracted oxygenation across the Cambrian–Ordovician transition: A key initiator of the Great Ordovician Biodiversification Event?". Geobiology. 21 (3): 323–340. doi:10.1111/gbi.12545. Retrieved 21 April 2023.
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  10. ^ a b Botting, Joseph P.; Muir, Lucy A. (28 June 2008). "Unravelling Causal Components of the Ordovician Radiation: the Builth Inlier (Central Wales) As a Case Study". Lethaia. 41 (2): 111–125. doi:10.1111/j.1502-3931.2008.00118.x. Retrieved 4 July 2023.
  11. ^ Miller, Arnold I.; Mao, Shuguang (1995-04-01). "Association of orogenic activity with the Ordovician radiation of marine life". Geology. 23 (4): 305–308. doi:10.1130/0091-7613(1995)023<0305:AOOAWT>2.3.CO;2. ISSN 0091-7613. PMID 11539503.
  12. ^ Cocks, L. Robin M.; Torsvik, Trond H. (December 2021). "Ordovician palaeogeography and climate change". Gondwana Research. 100: 53–72. doi:10.1016/j.gr.2020.09.008. Retrieved 26 May 2023.
  13. ^ Trotter, JA; Williams, IS; Barnes, CR; Lécuyer, C; Nicoll, RS (2008). "Did cooling oceans trigger Ordovician biodiversification? Evidence from conodont thermometry". Science. 321 (5888): 550–4. Bibcode:2008Sci...321..550T. doi:10.1126/science.1155814. PMID 18653889. S2CID 28224399.
  14. ^ Dronov, Andrei (1 November 2013). "Late Ordovician cooling event: Evidence from the Siberian Craton". Palaeogeography, Palaeoclimatology, Palaeoecology. 389: 87–95. doi:10.1016/j.palaeo.2013.05.032. Retrieved 20 October 2022.
  15. ^ Goldberg, Samuel L.; Present, Theodore M.; Finnegan, Seth; Bergmann, Kristin D. (2021-02-09). "A high-resolution record of early Paleozoic climate". Proceedings of the National Academy of Sciences of the United States of America. 118 (6): e2013083118. doi:10.1073/pnas.2013083118. ISSN 0027-8424. PMC 8017688. PMID 33526667.
  16. ^ Fan, Jun-xuan; Shen, Shu-zhong; Erwin, Douglas H.; Sadler, Peter M.; MacLeod, Norman; Cheng, Qiu-ming; Ho, Xu-dong; Yang, Jiao; Wang, Xiang-dong; Wang, Yue; Zhang, Hua; Chen, Xu; Li, Guo-xiang; Zhang, Yi-Chun; Shi, Yu-kun; Yuan, Dong-xun; Chen, Qing; Zhang, Lin-na; Li, Chao; Zhao, Ying-ying (17 January 2020). "A high-resolution summary of Cambrian to Early Triassic marine invertebrate biodiversity". Science. 367 (6475): 272–277. doi:10.1126/science.aax4953. Retrieved 5 July 2023.
  17. ^ Solved: Mystery of Earth's First Breathable Atmosphere
  18. ^ An extraterrestrial trigger for the mid-Ordovician ice age: Dust from the breakup of the L-chondrite parent body, Birger Schmitz et al, AAAS Science Advances, 18 Sep 2019: Vol. 5, no. 9, eaax4184; DOI: 10.1126/sciadv.aax4184, accessed 2019-10-09
  19. ^ Lindskog, A.; Costa, M. M.; Rasmussen, C.M.Ø.; Connelly, J. N.; Eriksson, M. E. (24 January 2017). "Refined Ordovician timescale reveals no link between asteroid breakup and biodiversification". Nature Communications. 8: 14066. doi:10.1038/ncomms14066. ISSN 2041-1723. PMC 5286199. PMID 28117834. It has been suggested that the Middle Ordovician meteorite bombardment played a crucial role in the Great Ordovician Biodiversification Event, but this study shows that the two phenomena were unrelated
  20. ^ McKie, Robin (12 October 2019). "New evidence shows how asteroid dust cloud may have sparked new life on Earth 470m years ago". The Observer. ISSN 0029-7712. Retrieved 12 October 2019.
  21. ^ "A mid-Darriwilian super volcano in northern New Brunswick, rapid climate change and the start of the great Ordovician biodiversification event" (PDF). Mineralogical Association of Canada. 2012. p. 119. Archived from the original (PDF) on 13 December 2019. Retrieved 15 September 2019.
  22. ^ All mineralized phyla were present by the end of the Cambrian; see Landing, E.; English, A.; Keppie, J. D. (2010). "Cambrian origin of all skeletalized metazoan phyla--Discovery of Earth's oldest bryozoans (Upper Cambrian, southern Mexico)". Geology. 38 (6): 547–550. Bibcode:2010Geo....38..547L. doi:10.1130/G30870.1.
  23. ^ a b Stigall, A.L; et al. (December 2016). "Biotic immigration events, speciation, and the accumulation of biodiversity in the fossil record". Global and Planetary Change. 148: 242–257. Bibcode:2017GPC...148..242S. doi:10.1016/j.gloplacha.2016.12.008.
  24. ^ a b Kröger, B. R.; Servais, T.; Zhang, Y.; Kosnik, M. (2009). Kosnik, Matthew (ed.). "The Origin and Initial Rise of Pelagic Cephalopods in the Ordovician". PLOS ONE. 4 (9): e7262. Bibcode:2009PLoSO...4.7262K. doi:10.1371/journal.pone.0007262. PMC 2749442. PMID 19789709.
  25. ^ Esteve, Jorge; López-Pachón, Matheo (1 September 2023). "Swimming and feeding in the Ordovician trilobite Microparia speciosa shed light on the early history of nektonic life habits". Palaeogeography, Palaeoclimatology, Palaeoecology. 625. doi:10.1016/j.palaeo.2023.111691. Retrieved 5 July 2023.
  26. ^ Serra, Fernanda; Balseiro, Diego; Waisfeld, Beatriz G. (1 April 2023). "Morphospace trends underlying a global turnover: Ecological dynamics of trilobite assemblages at the onset of the Ordovician Radiation". Palaeogeography, Palaeoclimatology, Palaeoecology. 615. doi:10.1016/j.palaeo.2023.111448. Retrieved 21 April 2023.
  27. ^ Harper, David A. T.; Cascales-Miñana, Borja; Servais, Thomas (3 December 2019). Geological Magazine. 157 (1): 5–21. doi:10.1017/S0016756819001298 https://www.cambridge.org/core/journals/geological-magazine/article/early-palaeozoic-diversifications-and-extinctions-in-the-marine-biosphere-a-continuum-of-change/2FC9A3CEEE131A2ADF202E83833CC319. Retrieved 4 July 2023. {{cite journal}}: Missing or empty |title= (help)
  28. ^ Servais, Thomas; Cascales-Miñana, Borja; Harper, David A. T.; Lefebvre, Bertrand; Munnecke, Axel; Wang, Wenhui; Zhang, Yuandong (1 August 2023). "No (Cambrian) explosion and no (Ordovician) event: A single long-term radiation in the early Palaeozoic". Palaeogeography, Palaeoclimatology, Palaeoecology. 623. doi:10.1016/j.palaeo.2023.111592. Retrieved 4 July 2023.
  29. ^ Harper, David A. T.; Topper, Timothy P.; Cascales-Miñana, Borja; Servais, Thomas; Zhang, Yuan-Dong; Ahlberg, Per (March–June 2019). "The Furongian (late Cambrian) Biodiversity Gap: Real or apparent?". Palaeoworld. 28 (1–2): 4–12. doi:10.1016/j.palwor.2019.01.007. Retrieved 4 July 2023.{{cite journal}}: CS1 maint: date format (link)
  30. ^ Deng, Yiying; Fan, Junxuan; Yang, Shengchao; Shi, Yukun; Lu, Zhengbo; Xu, Huiqing; Sun, Zongyuan; Zhao, Fangqi; Hou, Zhangshuai (15 May 2023). "No Furongian Biodiversity Gap: Evidence from South China". Palaeogeography, Palaeoclimatology, Palaeoecology. 618. doi:10.1016/j.palaeo.2023.111492. Retrieved 4 July 2023.
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