Devonian explosion

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Artist interpretation of a Devonian swamp forest scene. Artwork by Eduard Riou from The World Before the Deluge 1872 Devonianscene.jpg
Artist interpretation of a Devonian swamp forest scene. Artwork by Eduard Riou from The World Before the Deluge 1872

The Devonian explosion, also known as the Devonian Plant Explosion (DePE) [1] and the Silurian-Devonian Terrestrial Revolution, [2] [3] [4] was a period of rapid plant diversification that occurred 433 to 359 million years ago during the Silurian and Devonian, with the most critical phase occurring during the Late Silurian and Early Devonian. [5] This diversification of terrestrial plant life had vast impacts on the biotic composition of earth's soil, its atmosphere, its oceans, and for all plant and animal life that would follow it. [6] Through fierce competition for light and available space on land, phenotypic diversity of plants increased greatly, comparable in scale and effect to the explosion in diversity of animal life during the Cambrian Explosion, especially in vertical plant growth, which allowed for photoautotrophic canopies to develop, and forever altering plant evolutionary floras that followed. This Silurian and Devonian flora was significantly different in appearance, reproduction, and anatomy to most modern flora. Much of this flora had died out in extinction events including the Kellwasser Event, the Hangenberg Event, the Carboniferous Rainforest Collapse, and the End-Permian Extinction. [7] [8]

Contents

Silurian and Devonian life

The earliest radiations of the first land plants, also known as embryophytes, were bryophytes, which began to transform terrestrial environments and the global climate in the Ordovician. [9] During the Wenlock epoch of the Silurian, the first fossils of vascular plants appear in the fossil record in the form of sporophytes of polysporangiophytes. [10] Clubmosses first appeared during the later Ludlow epoch. [11] Palynological evidence points to Silurian terrestrial floras exhibiting little provincialism relative to present day floras that vary significantly by region, instead being broadly similar across the globe. [12] Plant diversification in the Silurian was aided by the presence of numerous small, rapidly changing volcanic islands in the Rheic Ocean that acted as natural laboratories accelerating evolutionary changes and enabling distinct, endemic floral lineages to arise. [13] Silurian plants rarely reached large sizes, with heights of 13 cm, achieved by Tichavekia grandis, being exceptionally large for the time. [14]

Basal members of Euphyllophytina, the clade that includes trimerophytes, ferns, progymnosperms, and seed plants, are known from Early Devonian fossils. [15] Devonian swamp forests were dominated by giant horsetails (Equisetales), clubmosses, ancestral ferns (pteridophytes), and large lycophyte vascular plants such as Lepidodendrales, referred to as scale trees for the appearance of scales on their photosynthetic trunks, and could grow up to 40 m high. These Lycophytes grew in great numbers around swamps along with tracheophytes. This increase in terrestrial plant matter in swamplands explains the deposits of coal and oil that would later characterize the Carboniferous. [7] Conifer-like spore producing trees with the first ever display of solid wood trunks developed in the Late Devonian. Seed ferns and true leaf-bearing plants such as progymnosperms also appeared at this time and became dominant in many habitats, particularly archeopteridaleans (likely related to conifers). Pseudosporochnaleans (related to palms and tree ferns) likewise experienced a similar rise to dominance. [16] Archeopteridaleans had likely developed extensive root systems, making them resistant to drought, and meaning they had a more significant impact on Devonian soil environments than pseudosporochnaleans. [17] Most flora in Devonian coal swamps would have seemed alien in appearance when compared with modern flora, such as giant horsetails which could grow up to 30 m in height. Devonian ancestral plants of modern plants that may have been very similar in appearance are ferns (Polypodiopsida), although many of them are thought to have been epiphytes rather than grounded plants. True gymnosperms like ginkgos (Ginkophyta) and cycads (Cycadophyta) would appear slightly after the Devonian in the Carboniferous. [7]

Vascular plant lineages of sphenoids, fern, progymnosperms, and seed plants evolved laminated leaves during the Devonian. Plants that possessed true leaves appeared during the Devonian, though they may have many independent origins with parallel trajectories of leaf morphologies. Morphological evidence to support this diversification theory appears in the Late Devonian or Early Carboniferous when compared with modern leaf morphologies. The marginal meristem also evolved in a parallel fashion through a similar process of modified structures around this time period. [18] In a 1994 study by Richard M Bateman and William A. Dimechele of the evolutionary history of heterospory in the plant kingdom, researchers found evidence of 11 origins of heterospory events that had occurred independently in the Devonian within Zosterophyllopsida, Sphenopsida, Progymnospermopsida. The effect of this heterospory was that it presented a primary evolutionary advantage for these plants in colonizing land. [19]

Effect on atmosphere, soil, and climate

Deep-rooted vascular plants had drastic impacts upon soil, atmosphere, and oceanic oxygen composition. The Devonian Plant Hypothesis is an explanation about these effects upon biogeomorphic ecosystems of climate and marine environments. [6] A climate/carbon/vegetation model could explain the effects of plant colonization during the Devonian. Land plant expansion of Devonian flora modified soil properties and there is evidence that atmospheric CO2 levels fell from around 6300 to 2100 ppmv as a result of carbon sequestration by land plants, while oxygen levels rose as a direct result of plant expansion. [20] The Devonian explosion had global consequences on oceanic nutrient content and sediment cycling, which had led to the Devonian mass extinction. The altering of soil composition created anoxic sedimentation (or black shales), oceanic acidification, and global climate changes. This led to harsh living conditions for oceanic and terrestrial life. [21]

Related Research Articles

<span class="mw-page-title-main">Devonian</span> Fourth period of the Paleozoic Era 419-359 million years ago

The Devonian is a geologic period and system of the Paleozoic, spanning 60.3 million years from the end of the Silurian, 419.2 million years ago (Mya), to the beginning of the Carboniferous, 358.9 Mya. It is named after Devon, England, where rocks from this period were first studied.

The PaleozoicEra is the earliest of three geologic eras of the Phanerozoic Eon. The name Paleozoic was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words palaiós and zōḗ, "life", meaning "ancient life").

<span class="mw-page-title-main">Silurian</span> Third period of the Paleozoic Era 444-419 million years ago

The Silurian is a geologic period and system spanning 24.6 million years from the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic Era. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out.

<span class="mw-page-title-main">Lagerstätte</span> Sedimentary deposit that exhibits extraordinary fossils with exceptional preservation

A Lagerstätte is a sedimentary deposit that exhibits extraordinary fossils with exceptional preservation—sometimes including preserved soft tissues. These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus delaying the decomposition of both gross and fine biological features until long after a durable impression was created in the surrounding matrix. Lagerstätten span geological time from the Neoproterozoic era to the present. Worldwide, some of the best examples of near-perfect fossilization are the Cambrian Maotianshan shales and Burgess Shale, the Silurian Waukesha Biota, the Devonian Hunsrück Slates and Gogo Formation, the Carboniferous Mazon Creek, the Jurassic Posidonia Shale and Solnhofen Limestone, the Cretaceous Yixian, Santana, and Agua Nueva formations, the Eocene Green River Formation, the Miocene Foulden Maar and Ashfall Fossil Beds, the Pliocene Gray Fossil Site, the Pleistocene Naracoorte Caves, the La Brea Tar Pits, and the Tanis Fossil Site.

<span class="mw-page-title-main">Late Devonian extinction</span> One of the five most severe extinction events in the history of the Earths biota

The Late Devonian extinction consisted of several extinction events in the Late Devonian Epoch, which collectively represent one of the five largest mass extinction events in the history of life on Earth. The term primarily refers to a major extinction, the Kellwasser event, which occurred around 372 million years ago, at the boundary between the Frasnian stage and the Famennian stage, the last stage in the Devonian Period. Overall, 19% of all families and 50% of all genera became extinct. A second mass extinction, the Hangenberg event, occurred 359 million years ago, bringing an end to the Famennian and Devonian, as the world transitioned into the Carboniferous Period.

<span class="mw-page-title-main">Cisuralian</span> First series of the Permian

The Cisuralian is the first series/epoch of the Permian. The Cisuralian was preceded by the Pennsylvanian and followed by the Guadalupian. The Cisuralian Epoch is named after the western slopes of the Ural Mountains in Russia and Kazakhstan and dates between 298.9 ± 0.15 – 272.3 ± 0.5 Mya.

<i>Baragwanathia</i> Extinct genus of spore-bearing plants

Baragwanathia is a genus of extinct lycopsid plants of Late Silurian to Early Devonian age, fossils of which have been found in Australia, Canada, China and Czechia. The name derives from William Baragwanath who discovered the first specimens of the type species, Baragwanathia longifolia, at Thomson River.

The Andean-Saharan glaciation, also known as the Early Palaeozoic Icehouse, the Early Palaeozoic Ice Age, the Late Ordovician glaciation, the end-Ordovician glaciation, or the Hirnantian glaciation, occurred during the Paleozoic from approximately 460 Ma to around 420 Ma, during the Late Ordovician and the Silurian period. The major glaciation during this period, which was formerly thought only to consist of the Hirnantian glaciation itself, but has now been recognized as a longer, more gradual event that began as early as the Darriwilian, is widely considered to be the leading cause of the Ordovician-Silurian extinction event. Evidence of this glaciation can be seen in places such as Arabia, North Africa, South Africa, Brazil, Peru, Bolivia, Chile, Argentina, and Wyoming. More evidence derived from isotopic data is that during the Late Ordovician, tropical ocean temperatures were about 5 °C cooler than present day; this would have been a major factor that aided in the glaciation process.

The Rheic Ocean was an ocean which separated two major palaeocontinents, Gondwana and Laurussia (Laurentia-Baltica-Avalonia). One of the principal oceans of the Palaeozoic, its sutures today stretch 10,000 km (6,200 mi) from Mexico to Turkey and its closure resulted in the assembly of the supercontinent Pangaea and the formation of the Variscan–Alleghenian–Ouachita orogenies.

The Hangenberg event, also known as the Hangenberg crisis or end-Devonian extinction, is a mass extinction that occurred at the end of the Famennian stage, the last stage in the Devonian Period. It is usually considered the second-largest extinction in the Devonian Period, having occurred approximately 13 million years after the Late Devonian mass extinction at the Frasnian-Famennian boundary. The Hangenberg event was an anoxic event marked by a layer of black shale, and it has been proposed to have been related to a rapid sea-level fall from the last phase of the Devonian Southern Hemisphere glaciation. It has also been suggested to have been linked to an increase in terrestrial plant cover. That would have led to increased nutrient supply in rivers and may have led to eutrophication of semi-restricted epicontinental seas and could have stimulated algal blooms. However, support for a rapid increase in plant cover at the end of the Famennian is lacking. The event is named after the Hangenberg Shale, which is part of a sequence that straddles the Devonian-Carboniferous boundary in the Rhenish Massif of Germany.

<span class="mw-page-title-main">Polysporangiophyte</span> Spore-bearing plants with branched sporophytes

Polysporangiophytes, also called polysporangiates or formally Polysporangiophyta, are plants in which the spore-bearing generation (sporophyte) has branching stems (axes) that bear sporangia. The name literally means 'many sporangia plant'. The clade includes all land plants (embryophytes) except for the bryophytes whose sporophytes are normally unbranched, even if a few exceptional cases occur. While the definition is independent of the presence of vascular tissue, all living polysporangiophytes also have vascular tissue, i.e., are vascular plants or tracheophytes. Extinct polysporangiophytes are known that have no vascular tissue and so are not tracheophytes.

<span class="mw-page-title-main">Noeggerathiales</span>

Noeggerathiales is a now-extinct order of vascular plants. The fossil range of the order extends from the Upper Carboniferous to the upper Permian (Lopingian). Due to gaps in the fossil record, the group is incompletely known and poorly defined, and their taxonomic status and position in the plant kingdom are uncertain. The Noeggerathiales have been proposed in the evolutionary scheme in two remotely related groups of vascular plants, the Pteropsida and the Sphenopsida.

This article attempts to place key plant innovations in a geological context. It concerns itself only with novel adaptations and events that had a major ecological significance, not those that are of solely anthropological interest. The timeline displays a graphical representation of the adaptations; the text attempts to explain the nature and robustness of the evidence.

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

<span class="mw-page-title-main">Carboniferous rainforest collapse</span> Extinction event at the end of the Moscovian in the Carboniferous

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<i>Chaetosalpinx</i> Trace fossil

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The Campbellton Formation is a geologic formation in New Brunswick. It preserves fossils dating back to the latest Pragian and Emsian of the Devonian period.

Olev Vinn is Estonian paleobiologist and paleontologist.

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References

  1. ↑ Pawlik, Łukasz; Buma, Brian; Šamonil, Pavel; Kvaček, Jiří; Gałązka, Anna; Kohout, Petr; Malik, Ireneusz (June 2020). "Impact of trees and forests on the Devonian landscape and weathering processes with implications to the global Earth's system properties - A critical review". Earth-Science Reviews. 205. doi:10.1016/j.earscirev.2020.103200 . Retrieved 12 November 2022.
  2. ↑ Capel, Elliot; Cleal, Christopher J.; Xue, Jinzhuang; Monnet, Claude; Servais, Thomas; Cascales-Miñana, Borja (August 2022). "The Silurian–Devonian terrestrial revolution: Diversity patterns and sampling bias of the vascular plant macrofossil record". Earth-Science Reviews . 231. doi:10.1016/j.earscirev.2022.104085 . Retrieved 8 November 2022.
  3. ↑ Xue, Jinzhuang; Huang, Pu; Wang, Deming; Xiong, Conghui; Liu, Le; Basinger, James F. (May 2018). "Silurian-Devonian terrestrial revolution in South China: Taxonomy, diversity, and character evolution of vascular plants in a paleogeographically isolated, low-latitude region". Earth-Science Reviews . 180: 92–125. doi:10.1016/j.earscirev.2018.03.004 . Retrieved 8 November 2022.
  4. ↑ Capel, Elliot; Cleal, Christopher J.; Gerrienne, P.; Servais, Thomas; Cascales-Miñana, Borja (15 March 2021). "A factor analysis approach to modelling the early diversification of terrestrial vegetation". Palaeogeography, Palaeoclimatology, Palaeoecology . 566. doi:10.1016/j.palaeo.2020.110170 . Retrieved 8 November 2022.
  5. ↑ Hao, Shougang; Xue, Jinzhuang; Liu, Zhenfeng; Wang, Deming (May 2007). "Zosterophyllum Penhallow around the Silurian‐Devonian Boundary of Northeastern Yunnan, China". International Journal of Plant Sciences . 168 (4): 477–489. doi:10.1086/511011 . Retrieved 12 November 2022.
  6. 1 2 Pawlik, Łukasz; Buma, Brian; Šamonil, Pavel; Kvaček, Jiří; Gałązka, Anna; Kohout, Petr; Malik, Ireneusz (June 2020). "Impact of trees and forests on the Devonian landscape and weathering processes with implications to the global Earth's system properties - A critical review". Earth-Science Reviews. 205: 103200. Bibcode:2020ESRv..20503200P. doi: 10.1016/j.earscirev.2020.103200 .
  7. 1 2 3 Cruzan, Mitchell (2018). Evolutionary Biology A Plant Perspective. New York: Oxford University Press. pp. 37–39. ISBN   978-0-19-088267-9.
  8. ↑ Cascales-Miñana, B.; Cleal, C. J. (2011). "Plant fossil record and survival analyses". Lethaia . 45: 71–82. doi:10.1111/j.1502-3931.2011.00262.x.
  9. ↑ Lenton, Timothy M.; Crouch, Michael; Johnson, Martin; Pires, Nuno; Dolan, Liam (1 February 2012). "First plants cooled the Ordovician". Nature Geoscience. 5 (2): 86–89. Bibcode:2012NatGe...5...86L. doi:10.1038/ngeo1390. ISSN   1752-0908 . Retrieved 18 October 2022.
  10. ↑ Libertín, Milan; Kvaček, Jiří; Bek, Jiří; Žárský, Viktor; Štorch, Petr (30 April 2018). "Sporophytes of polysporangiate land plants from the early Silurian period may have been photosynthetically autonomous". Nature Plants . 4: 269–271. doi:10.1038/s41477-018-0140-y . Retrieved 9 November 2022.
  11. ↑ Rickards, R. B. (1 March 2000). "The age of the earliest club mosses: the Silurian Baragwanathia flora in Victoria, Australia". Geological Magazine . 137 (2): 207–209. doi:10.1017/S0016756800003800 . Retrieved 11 November 2022.
  12. ↑ Césari, Silvia N.; Marenssi, Sergio; Limarino, Carlos O.; Ciccioli, Patricia L.; Bello, Fanny C.; Ferreira, Luis C.; Scarlatta, Leonardo R. (1 December 2020). "The first upper Silurian land-derived palynological assemblage from South America: Depositional environment and stratigraphic significance". Palaeogeography, Palaeoclimatology, Palaeoecology. 559. doi:10.1016/j.palaeo.2020.109970 . Retrieved 11 November 2022.
  13. ↑ Kraft, Petr; Pšenička, Josef; Sakala, Jakub; Frýda, Jiří (15 January 2019). "Initial plant diversification and dispersal event in upper Silurian of the Prague Basin". Palaeogeography, Palaeoclimatology, Palaeoecology . 514: 144–155. doi:10.1016/j.palaeo.2018.09.034 . Retrieved 9 November 2022.
  14. ↑ Uhlířová, Monika; Pšenička, Josef; Sakala, Jakub; Bek, Jiří (March 2022). "A study of the large Silurian land plant Tichavekia grandis Pšenička et al. from the Požáry Formation (Czech Republic)". Review of Palaeobotany and Palynology . 298. doi:10.1016/j.revpalbo.2021.104587 . Retrieved 11 November 2022.
  15. ↑ Xu, Hong-He; Wang, Yi; Tang, Peng; Fu, Qiang; Wang, Yao (1 October 2019). "Discovery of Lower Devonian plants from Jiangxi, South China and the pattern of Devonian transgression after the Kwangsian Orogeny in the Cathaysia Block". Palaeogeography, Palaeoclimatology, Palaeoecology. 531. doi:10.1016/j.palaeo.2018.11.007 . Retrieved 12 November 2022.
  16. ↑ Berry, Christopher M.; Marshall, John E.A. (December 2015). "Lycopsid forests in the early Late Devonian paleoequatorial zone of Svalbard". Geology. 43 (12): 1043–1046. Bibcode:2015Geo....43.1043B. doi: 10.1130/G37000.1 . ISSN   1943-2682.
  17. ↑ Meyer-Berthaud, B.; Soria, A.; Decombeix, A.-L. (2010). "The land plant cover in the Devonian: a reassessment of the evolution of the tree habit". Geological Society, London, Special Publications. 339 (1): 59–70. Bibcode:2010GSLSP.339...59M. doi:10.1144/SP339.6. ISSN   0305-8719.
  18. ↑ Boyce ; Knoll, C, A. (2002). "Evolution of developmental potential and the multiple independent origins of leaves in Paleozoic vascular plants". Paleobiology. 28 (1): 70–100. doi:10.1666/0094-8373(2002)028<0070:EODPAT>2.0.CO;2 – via DASH.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  19. ↑ Bateman, Richard M.; DiMICHELE, William A. (August 1994). "Heterospory: The Most Iterative Key Innovation in the Evolutionary History of the Plant Kingdom". Biological Reviews. 69 (3): 345–417. doi:10.1111/j.1469-185X.1994.tb01276.x. ISSN   1464-7931.
  20. ↑ Le Hir, Guillaume; Donnadieu, Yannick; Goddéris, Yves; Meyer-Berthaud, Brigitte; Ramstein, Gilles; Blakey, Ronald C. (October 2011). "The climate change caused by the land plant invasion in the Devonian". Earth and Planetary Science Letters. 310 (3–4): 203–212. Bibcode:2011E&PSL.310..203L. doi:10.1016/j.epsl.2011.08.042.
  21. ↑ Becker, R. T.; Königshof, P.; Brett, C. E. (2016). "Devonian climate, sea level and evolutionary events: an introduction". Geological Society, London, Special Publications. 423 (1): 1–10. Bibcode:2016GSLSP.423....1B. doi: 10.1144/SP423.15 . ISSN   0305-8719.
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