Difference between revisions of "Cambrian"
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The Cambrian was named by the geologist [[Adam Sedgwick]] for Cambria,<ref>http://www.ucmp.berkeley.edu/history/sedgwick.html</ref> Latin for [[Wales]], which has large areas of rock originating in, and characteristic of, the period. | The Cambrian was named by the geologist [[Adam Sedgwick]] for Cambria,<ref>http://www.ucmp.berkeley.edu/history/sedgwick.html</ref> Latin for [[Wales]], which has large areas of rock originating in, and characteristic of, the period. | ||
| − | + | Common Cambrian [[fossil]]s are of [[trilobite]]s, and inarticulate [[brachiopod]]s,<ref>http://www.palaeos.com/Paleozoic/Cambrian/Cambrian.htm#bio</ref> [[coral]]s and primitive [[echinoderm]]s. They also include what are considered by evolutionists to be the first [[vertebrate]]s, "primitive" jawless fish. | |
| − | + | Fossil remains other than shells or carapaces are rare. One notable site for soft-bodied Cambrian invertebrate remains is the [[Burgess Shale]] of [[British Columbia]].<ref>http://wwwalt.uni-wuerzburg.de/palaeontologie/Stuff/casu9.htm</ref> | |
| − | + | == Era and evolution == | |
| − | + | Under the uniformitarian dates assigned by secular geologists, it represents approximately the period of Earth's history from about 542 million years ago to 488 million years ago.<ref>Gradstein, F.M., and Ogg, J.G.,[http://www.stratigraphy.org/scale04.pdf Geologic Time Scale 2004 – Why, How, and Where Next!]</ref> Young Earth creationists reject the uniformitarian assumptions behind the dates derived by secular geologists, so they reject these dates (see [[geologic system]]). Instead, most would consider the Cambrian sediment to be early [[Flood Geology|Flood]] deposits.<ref>Snelling, Andrew, ''Radiohalos in Granite'', chapter 5 of DeYoung, Don, "Thousands, Not Billions", Master Books, 2005, p.89, ISBN 0-89051-441-0.</ref> | |
Evolutionists believe that the [[Cambrian Radiation]] gave rise to almost all living phyla, but often in extinct forms with small resemblance to typical living species. | Evolutionists believe that the [[Cambrian Radiation]] gave rise to almost all living phyla, but often in extinct forms with small resemblance to typical living species. | ||
| + | The rarity of shells or carapaces leads evolutionists to conclude that many of the organisms of the time were soft-bodied [[invertebrate]]s. | ||
==References== | ==References== | ||
Revision as of 13:38, December 23, 2007
The Cambrian period is part of the geologic system of classifying geologic formations.
Description
The Cambrian period is the first period of the Paleozoic era, and is divided into Early, Middle, and Furongian epochs. The Cambrian is preceded by the Precambrian era and followed by the Ordovician era.
The Cambrian was named by the geologist Adam Sedgwick for Cambria,[1] Latin for Wales, which has large areas of rock originating in, and characteristic of, the period.
Common Cambrian fossils are of trilobites, and inarticulate brachiopods,[2] corals and primitive echinoderms. They also include what are considered by evolutionists to be the first vertebrates, "primitive" jawless fish.
Fossil remains other than shells or carapaces are rare. One notable site for soft-bodied Cambrian invertebrate remains is the Burgess Shale of British Columbia.[3]
Era and evolution
Under the uniformitarian dates assigned by secular geologists, it represents approximately the period of Earth's history from about 542 million years ago to 488 million years ago.[4] Young Earth creationists reject the uniformitarian assumptions behind the dates derived by secular geologists, so they reject these dates (see geologic system). Instead, most would consider the Cambrian sediment to be early Flood deposits.[5]
Evolutionists believe that the Cambrian Radiation gave rise to almost all living phyla, but often in extinct forms with small resemblance to typical living species. The rarity of shells or carapaces leads evolutionists to conclude that many of the organisms of the time were soft-bodied invertebrates.
References
- ↑ http://www.ucmp.berkeley.edu/history/sedgwick.html
- ↑ http://www.palaeos.com/Paleozoic/Cambrian/Cambrian.htm#bio
- ↑ http://wwwalt.uni-wuerzburg.de/palaeontologie/Stuff/casu9.htm
- ↑ Gradstein, F.M., and Ogg, J.G.,Geologic Time Scale 2004 – Why, How, and Where Next!
- ↑ Snelling, Andrew, Radiohalos in Granite, chapter 5 of DeYoung, Don, "Thousands, Not Billions", Master Books, 2005, p.89, ISBN 0-89051-441-0.