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Avalon explosion
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<h2 id="history">History</h2> <p><a href="/facts/Charles_Darwin/uwDLGItY">Charles Darwin</a> predicted a time of ecological growth before the Cambrian Period, but there was no evidence to support it until the Avalon explosion was proposed in 2008 by <a href="/facts/Virginia_Tech/5nNYd0ur">Virginia Tech</a> <a href="/facts/Paleontologists/60n5yldd">paleontologists</a> after analysis of the morphological space change in several <a href="/facts/Ediacaran/z8jSUITT">Ediacaran</a> assemblages.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a><a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> The discovery suggests that the early evolution of <a href="/facts/Animals/4b8J33nd">animals</a> may have involved more than one explosive event.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> The original analysis has been the subject of dispute in the literature.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a><a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a><a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p> <h2 id="evidence">Evidence</h2> <p>Trace fossils of these Avalon organisms have been found worldwide, with many found in <a href="/facts/Newfoundland_(island)/PdfPl9ca">Newfoundland</a>, in Canada and the <a href="/facts/Charnwood_Forest/fmp1ptct">Charnwood Forest</a> in England,<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> representing the earliest known complex <a href="/facts/Multicellular_organism/rk8QBF7o">multicellular organisms</a>.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> The Avalon explosion theoretically produced the <a href="/facts/Ediacaran_biota/1lx1CXxT">Ediacaran biota</a>.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a><a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> The biota largely disappeared contemporaneously with the rapid increase in <a href="/facts/Biodiversity/GruakEzs">biodiversity</a> known as the Cambrian explosion. At this time, all living animal groups were present in the Cambrian oceans.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> </p><p>The Avalon explosion appears similar to the Cambrian explosion in the rapid increase in diversity of <a href="/facts/Morphology_(biology)/Nl3B0myy">morphologies</a> in a relatively small-time frame, followed by diversification within the established <a href="/facts/Body_plan/TykqU5bY">body plans</a>,<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a><a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> a pattern similar to that observed in other evolutionary events.<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> </p> <h2 id="plants-and-animals">Plants and animals</h2> <p>The Avalon explosion was a time of early evolution and low diversity in species. There were over 270 species defined,<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> with 50 different morphological characteristics categories, many of whose anatomical structures had to be inferred with fossils and casts.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a><a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> These species were placed into 20 different genera.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> </p><p>During this time, animals became bilateral and along with increasing complexity.<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a> Many animals during this time fit into the <a href="/facts/Annelid/PQvb7NAM">annelid</a>, <a href="/facts/Arthropod/JKJLTFzp">arthropod</a>, <a href="/facts/Echinoderm/j2rd8qwt">echinoderm</a>, and <a href="/facts/Cnidarian/d0HRc6w0">cnidarian</a> <a href="/facts/Phylum/ELT3Jyax">phyla</a>.<a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> Animals at this time developed bilateral symmetry with a clear anterior and posterior side, which included species like <i><a href="/facts/Spriggina/6r1EfuT9">Spriggina</a></i>, <i><a href="/facts/Charniodiscus/wS89C8RX">Charniodiscus</a></i> and <i><a href="/facts/Yorgia/GlGp3PKr">Yorgia</a></i>.<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a> </p><p>Many of the plants fit into a now-extinct phylum of <a href="/facts/Vendobionta/1lx1CXxT">Vendobionta</a>.<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> The Vendobionta were arranged several ways - some radial, some parallel, some concentric.<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a> <i>Frondlets</i> were a prominent aquatic plant during this time, with many different shapes, including <i><a href="/facts/Fractofusus/bMvChIVt">Fractofusus</a></i> which is a spindle shape, <i>Fradgatia</i>, a lettuce shape, and <i><a href="/facts/Rangea/K0sA3Tn1">Rangea</a></i> which was a leaf shape.<a class="footnote-ref" id="fnref:28" href="#fn:28"><sup>28</sup></a> </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Cambrian_explosion/Wg29M7PN">Cambrian explosion</a></li> <li><a href="/facts/Carboniferous-Earliest_Permian_Biodiversification_Event/BRKlkYyd">Carboniferous-Earliest Permian Biodiversification Event</a></li> <li><a href="/facts/Great_Ordovician_Biodiversification_Event/z6wbnBnq">Great Ordovician Biodiversification Event</a></li></ul> <h2 id="notes">Notes</h2> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>"Two Explosive Evolutionary Events Shaped Early History Of Multicellular Life" (Press release). Virginia Tech. January 4, 2008. Retrieved 2018-03-06 – via ScienceDaily. <a href="https://www.sciencedaily.com/releases/2008/01/080103144451.htm" target="_blank">https://www.sciencedaily.com/releases/2008/01/080103144451.htm</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>"Two Explosive Evolutionary Events Shaped Early History Of Multicellular Life" (Press release). Virginia Tech. January 4, 2008. Retrieved 2018-03-06 – via ScienceDaily. <a href="https://www.sciencedaily.com/releases/2008/01/080103144451.htm" target="_blank">https://www.sciencedaily.com/releases/2008/01/080103144451.htm</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>"The Avalon Explosion". Astrobiology Magazine. 8 January 2008. Archived from the original on 2 August 2012. Retrieved 14 June 2012. <a href="https://web.archive.org/web/20120802024234/http://www.astrobio.net/pressrelease/2580/the-avalon-explosion" target="_blank">https://web.archive.org/web/20120802024234/http://www.astrobio.net/pressrelease/2580/the-avalon-explosion</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>Freeman, Gary (2009). "The rise of bilaterians". Historical Biology. 21 (1–2): 99–114. Bibcode:2009HBio...21...99F. doi:10.1080/08912960903295843. S2CID 83841216. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>Xiao, Shuhai; Kowalewski, Michał; Shen, Bing; Dong, Lin; Laflamme, Marc (8 January 2010). "The rise of bilaterians: a reply". Historical Biology. 21 (3–4): 239–246. doi:10.1080/08912960903471659. S2CID 84488359. <a href="/wiki/Historical_Biology" target="_blank">/wiki/Historical_Biology</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>Freeman, Gary (30 June 2010). "Comment on Xiao et al. (2009), response to: the rise of bilaterians". Historical Biology. 22 (4): 430–432. Bibcode:2010HBio...22..430F. doi:10.1080/08912960903562259. S2CID 85339496. <a href="/wiki/Bibcode_(identifier)" target="_blank">/wiki/Bibcode_(identifier)</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>Simple multicellular organisms such as red algae evolved at least 1,200 million years ago. <a href="/wiki/Red_algae" target="_blank">/wiki/Red_algae</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>"Two Explosive Evolutionary Events Shaped Early History Of Multicellular Life" (Press release). Virginia Tech. January 4, 2008. Retrieved 2018-03-06 – via ScienceDaily. <a href="https://www.sciencedaily.com/releases/2008/01/080103144451.htm" target="_blank">https://www.sciencedaily.com/releases/2008/01/080103144451.htm</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> <li id="fn:14"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:14" class="footnote-back-ref">↩</a></p></li> <li id="fn:15"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:15" class="footnote-back-ref">↩</a></p></li> <li id="fn:16"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="/wiki/Science_(journal)" target="_blank">/wiki/Science_(journal)</a> <a href="#fnref:16" class="footnote-back-ref">↩</a></p></li> <li id="fn:17"><p>Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution. 24 (1): 31–40. Bibcode:2009TEcoE..24...31X. doi:10.1016/j.tree.2008.07.015. PMID 18952316. <a href="/wiki/Trends_in_Ecology_%26_Evolution" target="_blank">/wiki/Trends_in_Ecology_%26_Evolution</a> <a href="#fnref:17" class="footnote-back-ref">↩</a></p></li> <li id="fn:18"><p>Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution. 24 (1): 31–40. Bibcode:2009TEcoE..24...31X. doi:10.1016/j.tree.2008.07.015. PMID 18952316. <a href="/wiki/Trends_in_Ecology_%26_Evolution" target="_blank">/wiki/Trends_in_Ecology_%26_Evolution</a> <a href="#fnref:18" class="footnote-back-ref">↩</a></p></li> <li id="fn:19"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="https://www.science.org/doi/10.1126/science.1150279" target="_blank">https://www.science.org/doi/10.1126/science.1150279</a> <a href="#fnref:19" class="footnote-back-ref">↩</a></p></li> <li id="fn:20"><p>"Two Explosive Evolutionary Events Shaped Early History Of Multicellular Life" (Press release). Virginia Tech. January 4, 2008. Retrieved 2018-03-06 – via ScienceDaily. <a href="https://www.sciencedaily.com/releases/2008/01/080103144451.htm" target="_blank">https://www.sciencedaily.com/releases/2008/01/080103144451.htm</a> <a href="#fnref:20" class="footnote-back-ref">↩</a></p></li> <li id="fn:21"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="https://www.science.org/doi/10.1126/science.1150279" target="_blank">https://www.science.org/doi/10.1126/science.1150279</a> <a href="#fnref:21" class="footnote-back-ref">↩</a></p></li> <li id="fn:22"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="https://www.science.org/doi/10.1126/science.1150279" target="_blank">https://www.science.org/doi/10.1126/science.1150279</a> <a href="#fnref:22" class="footnote-back-ref">↩</a></p></li> <li id="fn:23"><p>Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution. 24 (1): 31–40. Bibcode:2009TEcoE..24...31X. doi:10.1016/j.tree.2008.07.015. ISSN 0169-5347. PMID 18952316. <a href="https://pubmed.ncbi.nlm.nih.gov/18952316" target="_blank">https://pubmed.ncbi.nlm.nih.gov/18952316</a> <a href="#fnref:23" class="footnote-back-ref">↩</a></p></li> <li id="fn:24"><p>Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution. 24 (1): 31–40. Bibcode:2009TEcoE..24...31X. doi:10.1016/j.tree.2008.07.015. ISSN 0169-5347. PMID 18952316. <a href="https://pubmed.ncbi.nlm.nih.gov/18952316" target="_blank">https://pubmed.ncbi.nlm.nih.gov/18952316</a> <a href="#fnref:24" class="footnote-back-ref">↩</a></p></li> <li id="fn:25"><p>Shen, Bing; Dong, Lin; Xiao, Shuhai; Kowalewski, Michał (4 January 2008). "The Avalon Explosion: Evolution of Ediacara Morphospace". Science. 319 (5859): 81–84. Bibcode:2008Sci...319...81S. doi:10.1126/science.1150279. ISSN 0036-8075. PMID 18174439. S2CID 206509488. <a href="https://www.science.org/doi/10.1126/science.1150279" target="_blank">https://www.science.org/doi/10.1126/science.1150279</a> <a href="#fnref:25" class="footnote-back-ref">↩</a></p></li> <li id="fn:26"><p>Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution. 24 (1): 31–40. Bibcode:2009TEcoE..24...31X. doi:10.1016/j.tree.2008.07.015. ISSN 0169-5347. PMID 18952316. <a href="https://pubmed.ncbi.nlm.nih.gov/18952316" target="_blank">https://pubmed.ncbi.nlm.nih.gov/18952316</a> <a href="#fnref:26" class="footnote-back-ref">↩</a></p></li> <li id="fn:27"><p>Peterson1, Kevin J.; Waggoner, Ben; Hagadorn, James W. (February 2003). "A fungal analog for Newfoundland Ediacaran fossils?". Integrative and Comparative Biology. 43 (1): 127–136. doi:10.1093/icb/43.1.127. PMID 21680417.{{cite journal}}: CS1 maint: numeric names: authors list (link) <a href="https://academic.oup.com/icb/article/43/1/127/604481" target="_blank">https://academic.oup.com/icb/article/43/1/127/604481</a> <a href="#fnref:27" class="footnote-back-ref">↩</a></p></li> <li id="fn:28"><p>Xiao, Shuhai; Laflamme, Marc (January 2009). "On the eve of animal radiation: phylogeny, ecology and evolution of the Ediacara biota". Trends in Ecology & Evolution. 24 (1): 31–40. Bibcode:2009TEcoE..24...31X. doi:10.1016/j.tree.2008.07.015. ISSN 0169-5347. PMID 18952316. <a href="https://pubmed.ncbi.nlm.nih.gov/18952316" target="_blank">https://pubmed.ncbi.nlm.nih.gov/18952316</a> <a href="#fnref:28" class="footnote-back-ref">↩</a></p></li> </ol>