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2019-11-21 09:02:50.0 [tstevens] Insert Concept
add narrower relation (SILURIAN [3be2d037-28aa-40c7-8877-530fbcaa2c03,396411] - PRIDOLI
[38271019-de23-4b2e-85ed-15af2f3a11bc,423493]);
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2019-11-21 09:03:14.0 [tstevens] Insert Concept
add narrower relation (SILURIAN [3be2d037-28aa-40c7-8877-530fbcaa2c03,396411] - LUDLOW
[15256b96-f71f-43d2-8c1b-ab5dca5dd3db,423497]);
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2019-11-21 09:03:33.0 [tstevens] Insert Concept
add narrower relation (SILURIAN [3be2d037-28aa-40c7-8877-530fbcaa2c03,396411] - WENLOCK
[cda42e0a-bac4-4ca6-b20d-c09b45e8717b,423501]);
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2019-11-21 09:03:52.0 [tstevens] Insert Concept
add narrower relation (SILURIAN [3be2d037-28aa-40c7-8877-530fbcaa2c03,396411] - LLANDOVERY
[ec205df2-0e6a-4ffe-a7f6-8f20592345f7,423505]);
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2019-12-17 12:15:17.0 [tstevens]
insert Definition (id: null
text: The Silurian is a geologic period and system spanning 24.6 million years from
the end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning
of the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic
Era. As with other geologic periods, the rock beds that define the period's start
and end are well identified, but the exact dates are uncertain by several million
years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction
events when up to 60% of marine genera were wiped out. A significant evolutionary
milestone during the Silurian was the diversification of jawed fish and bony fish.
Multi-cellular life also began to appear on land in the form of small, bryophyte-like
and vascular plants that grew beside lakes, streams, and coastlines, and terrestrial
arthropods are also first found on land during the Silurian. However, terrestrial
life would not greatly diversify and affect the landscape until the Devonian.
language code: en);
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| definition |
The Silurian is a geologic period and system spanning 24.6 million years from the
end of the Ordovician Period, at 443.8 million years ago (Mya), to the beginning of
the Devonian Period, 419.2 Mya. The Silurian is the shortest period of the Paleozoic
Era. As with other geologic periods, the rock beds that define the period's start
and end are well identified, but the exact dates are uncertain by several million
years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction
events when up to 60% of marine genera were wiped out. A significant evolutionary
milestone during the Silurian was the diversification of jawed fish and bony fish.
Multi-cellular life also began to appear on land in the form of small, bryophyte-like
and vascular plants that grew beside lakes, streams, and coastlines, and terrestrial
arthropods are also first found on land during the Silurian. However, terrestrial
life would not greatly diversify and affect the landscape until the Devonian.
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