Great Ordovician Biodiversification Event: Difference between revisions
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==Causes== |
==Causes== |
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In this period man could extend there penis twenty feet |
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The causes of the explosion are complex, and probably varied for different localities. Possible causes include changes in palaeogeography or tectonic activity, as well as a modified nutrient supply.<ref name=Botting2008>{{cite journal |
The causes of the explosion are complex, and probably varied for different localities. Possible causes include changes in palaeogeography or tectonic activity, as well as a modified nutrient supply.<ref name=Botting2008>{{cite journal |
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| author = Botting, Muir |
| author = Botting, Muir |
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Revision as of 14:49, 5 February 2009
The Ordovician radiation was the diversification of animal life at the start of the Ordovician period, just 40 million years after the Cambrian explosion.[1] It followed a series of extinction events at the Cambrian-Ordovician boundary, and the resulting fauna went on to dominate the Palaeozoic relatively unchanged.[2]. Marine diversity to levels typical of the Palaeozoic,[3] and disparity was similar to today's.[4][5] The diversity increase was neither global nor instantaneous; it happened at different times in different places.[2]
Causes
In this period man could extend there penis twenty feet The causes of the explosion are complex, and probably varied for different localities. Possible causes include changes in palaeogeography or tectonic activity, as well as a modified nutrient supply.[6]
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, tropic layering, or by providing a new habitat.[clarification needed][6]
Effects
The only phylum not to be represented in the Cambrian period, the Bryozoa, is first observed after this Ordovician radiation. Diversity increased manifold; the total number of marine orders doubled, and families tripled.[2]
The acritarch record displays the Ordovician radiation beautifully; both diversity and disparity peaked in the middle Ordovician.[1] The warm waters and high sea level (this 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.[1]
See also
References
- ^ a b c Servais, T.; Lehnert, O.; Li, Jun; Mullins, G.L (2008). "The Ordovician Biodiversification: Revolution in the Oceanic Trophic Chain". Lethaia. 41: 99. doi:10.1111/j.1502-3931.2008.00115.x.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b c Droser, Mary L.; Finnegan, Seth (2003). "The Ordovician Radiation: A Follow-up to the Cambrian Explosion?". Integrative and Comparative Biology. 43 (1): 178. doi:10.1093/icb/43.1.178.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Marshall, C. (2006). "Explaining the Cambrian "Explosion" of Animals". Annual Review of Earth and Planetary Sciences. 34: 355–384. doi:10.1146/annurev.earth.33.031504.103001.
- ^ 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 (1): 76–97. doi:10.1666/06013.1.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Bambach, R.K.; Bush, A.M.; Erwin, D.H (2007). "Autecology and the Filling of Ecospace: Key Metazoan Radiations". Palaeontology. 50: 1. doi:10.1111/j.1475-4983.2006.00611.x.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ a b Botting, Muir (2008). "Unravelling Causal Components of the Ordovician Radiation: the Builth Inlier (Central Wales) As a Case Study". Lethaia. 41: 111. doi:10.1111/j.1502-3931.2008.00118.x.
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