Cambrian

This Marrella specimen shows how clear and detailed the fossils are from the Burgess Shale lagerstätte.
Dickinsonia, an Ediacaran animal with a quilted appearance.
A fossilized trilobite. This specimen of Olenoides serratus, from the Burgess shale, preserves 'soft parts' – the antennae and legs.

The Cambrian is the first geological period of the Palaeozoic era. It lasted from 541 million years ago to 485.4 million years ago.[1] Before it came the Ediacaran, and after it the Ordovician.

Biologists have learnt quite a lot about the soft parts of Cambrian animals. This is because places have been found where soft parts of organisms are preserved as well as their more resistant shells. This means our understanding of the Cambrian biota is better than that of some later periods.

Life on Earth changed greatly during the Cambrian period. Before the Cambrian, life was mostly small and simple. Complex organisms (metazoa) evolved during the Proterozoic era. But during the Cambrian period, some organisms used carbonate minerals for shells, so they had hard parts which could become fossils. There were many different kinds of life during the Cambrian period. This increase in the diversity of lifeforms was relatively rapid, and is called the Cambrian explosion. This adaptive radiation produced the first members of the main groups of animals, called phyla.

Almost all of this new life was in the oceans. There was little life on land except a layer of microbes. There were shallow seas near several continents, because a supercontinent called Pannotia had broken into smaller pieces. The seas were warm, and there was no ice at the North and South Pole. Many animals with hard shells appeared for the first time during the beginning of the Cambrian.

Change in the sea floor

At the start of the Cambrian, the earlier animals (the Ediacaran biota) may have become extinct.[2] It seems these older life forms were affected by new types which burrowed into the sea floor.[3] This changed the conditions of life for the older types. The burrowing must have disturbed the mat of bacteria and algae which covered the sea-floor. About this time we find the first examples of many phyla. There are also some fossil traces on what was land at the time, so perhaps a few Cambrian organisms did leave the water.

Other Languages
Afrikaans: Kambrium
Alemannisch: Kambrium
asturianu: Cambrianu
Bahasa Banjar: Kambrium
Bân-lâm-gú: Cambria-kí
беларуская: Кембрыйскі перыяд
беларуская (тарашкевіца)‎: Кембр
български: Камбрий
brezhoneg: Kambrian
català: Cambrià
čeština: Kambrium
Cymraeg: Cambriaidd
dansk: Kambrium
Deutsch: Kambrium
eesti: Kambrium
English: Cambrian
español: Cámbrico
Esperanto: Kambrio
euskara: Kanbriar
فارسی: کامبرین
français: Cambrien
Gaeilge: Caimbriach
galego: Cámbrico
한국어: 캄브리아기
hrvatski: Kambrij
Bahasa Indonesia: Kambrium
italiano: Cambriano
עברית: קמבריון
Basa Jawa: Kambriyum
Latina: Cambrium
latviešu: Kembrijs
Lëtzebuergesch: Kambrium
lietuvių: Kambras
Limburgs: Cambrium
magyar: Kambrium
македонски: Камбриум
مازِرونی: کامبرین
Bahasa Melayu: Kambria
Mìng-dĕ̤ng-ngṳ̄: Cambrian
Nederlands: Cambrium
Nordfriisk: Kambrium
norsk: Kambrium
norsk nynorsk: Kambrium
occitan: Cambrian
oʻzbekcha/ўзбекча: Kembriy sistemasi
پنجابی: کیمبرین
Piemontèis: Cambrian
polski: Kambr
português: Cambriano
română: Cambrian
саха тыла: Кембрий
Scots: Cambrian
slovenčina: Kambrium
slovenščina: Kambrij
српски / srpski: Камбријум
srpskohrvatski / српскохрватски: Kambrij
svenska: Kambrium
Tagalog: Cambrian
Tiếng Việt: Kỷ Cambri
Volapük: Kambrium
文言: 寒武紀
Winaray: Cambrian
吴语: 寒武纪
粵語: 寒武紀
中文: 寒武纪