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2019-12-17 13:07:24.0 [tstevens] Insert Concept
add narrower relation (CAMBRIAN [167bba30-03d3-4898-8c53-6e50828d1749,505123] - FURONGIAN
[d5a694f5-630e-4164-8789-aaa164a5e34a,532291]);
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2019-12-17 13:08:08.0 [tstevens] Insert Concept
add narrower relation (CAMBRIAN [167bba30-03d3-4898-8c53-6e50828d1749,505123] - MIAOLINGIAN
[ea5250b7-79a4-4f27-a5c5-9ebd41ab627b,532295]);
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2019-12-17 13:08:28.0 [tstevens] Insert Concept
add narrower relation (CAMBRIAN [167bba30-03d3-4898-8c53-6e50828d1749,505123] - SERIES
2 [c98a4c91-1b1d-464d-8380-497a186db7eb,532299]);
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2019-12-17 13:08:55.0 [tstevens] Insert Concept
add narrower relation (CAMBRIAN [167bba30-03d3-4898-8c53-6e50828d1749,505123] - TERRENEUVIAN
[411f36cf-8c87-474c-bfaf-614723a4b938,532303]);
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2019-12-18 16:03:50.0 [tstevens]
insert Definition (id: null
text: The Cambrian Period was the first geological period of the Paleozoic Era, and
of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the
preceding Ediacaran Period 541 million years ago (mya) to the beginning of the Ordovician
Period 485.4 mya. The Cambrian is unique in its unusually high proportion of lagerstätte
sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms
are preserved as well as their more resistant shells. As a result, our understanding
of the Cambrian biology surpasses that of some later periods. The Cambrian marked
a profound change in life on Earth; prior to the Cambrian, the majority of living
organisms on the whole were small, unicellular and simple; the Precambrian Charnia
being exceptional. Complex, multicellular organisms gradually became more common in
the millions of years immediately preceding the Cambrian, but it was not until this
period that mineralized—hence readily fossilized—organisms became common. The rapid
diversification of life forms in the Cambrian, known as the Cambrian explosion, produced
the first representatives of all modern animal phyla. Phylogenetic analysis has supported
the view that during the Cambrian radiation, metazoa (animals) evolved monophyletically
from a single common ancestor: flagellated colonial protists similar to modern choanoflagellates.
Although diverse life forms prospered in the oceans, the land is thought to have been
comparatively barren—with nothing more complex than a microbial soil crust and a few
molluscs that emerged to browse on the microbial biofilm. Most of the continents were
probably dry and rocky due to a lack of vegetation. Shallow seas flanked the margins
of several continents created during the breakup of the supercontinent Pannotia. The
seas were relatively warm, and polar ice was absent for much of the period.
language code: en);
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| definition |
The Cambrian Period was the first geological period of the Paleozoic Era, and of the
Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding
Ediacaran Period 541 million years ago (mya) to the beginning of the Ordovician Period
485.4 mya. The Cambrian is unique in its unusually high proportion of lagerstätte
sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms
are preserved as well as their more resistant shells. As a result, our understanding
of the Cambrian biology surpasses that of some later periods. The Cambrian marked
a profound change in life on Earth; prior to the Cambrian, the majority of living
organisms on the whole were small, unicellular and simple; the Precambrian Charnia
being exceptional. Complex, multicellular organisms gradually became more common in
the millions of years immediately preceding the Cambrian, but it was not until this
period that mineralized—hence readily fossilized—organisms became common. The rapid
diversification of life forms in the Cambrian, known as the Cambrian explosion, produced
the first representatives of all modern animal phyla. Phylogenetic analysis has supported
the view that during the Cambrian radiation, metazoa (animals) evolved monophyletically
from a single common ancestor: flagellated colonial protists similar to modern choanoflagellates.
Although diverse life forms prospered in the oceans, the land is thought to have been
comparatively barren—with nothing more complex than a microbial soil crust and a few
molluscs that emerged to browse on the microbial biofilm. Most of the continents were
probably dry and rocky due to a lack of vegetation. Shallow seas flanked the margins
of several continents created during the breakup of the supercontinent Pannotia. The
seas were relatively warm, and polar ice was absent for much of the period.
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