Paleozoic era


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Related to Paleozoic era: Cambrian period, Precambrian era

See also: Geologic Timescale (table)Geologic Timescale
Era Period Epoch Approximate duration
(millions of years)
Approximate number of years ago
(millions of years)

Cenozoic Quaternary Holocene 10,000 years ago to the present  
Pleistocene 2 .
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Paleozoic era

(pā'lēəzō`ĭk), a major division (era) of geologic time (see Geologic TimescaleGeologic Timescale
Era Period Epoch Approximate duration
(millions of years)
Approximate number of years ago
(millions of years)

Cenozoic Quaternary Holocene 10,000 years ago to the present  
Pleistocene 2 .
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, table) occurring between 570 to 240 million years ago. It is subdivided into six periods, the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (see each listed individually). During the hiatus between the late PrecambrianPrecambrian,
name of a major division of geologic time (see Geologic Timescale, table), from c.5 billion to 570 million years ago. It is now usually divided into the Archean and Proterozoic eons. Precambrian time includes 80% of the earth's history.
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 and the Paleozoic era most of the evidence of the earth's early history was destroyed by erosion. From the beginning of the Paleozoic, shallow seas began to encroach on the continents. In North America, the era began with submerged geosynclines, or downward thrusts of the earth's crust, along the eastern, southeastern, and western sides of the continent, while the interior was dry land. As the era proceeded, the marginal seas periodically washed over the stable interior, leaving sedimentary deposits to mark their incursions. During the early part of the era, the area of exposed Precambrian, or shield, rocks in central Canada were eroding, supplying sediment to the geosynclines from the interior. Beginning in the Ordovician periodOrdovician period
[from the Ordovices, ancient tribe of N Wales], second period of the Paleozoic era of geologic time (see Geologic Timescale, table) from 505 to 438 million years ago.
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, mountain building intermittently proceeded in the eastern part of the Appalachian geosyncline throughout the rest of the era, bringing in new sediments. Sediments washing from the Acadian Mts. filled the western part of the Appalachian geosyncline to form the famous coal swamps of the Carboniferous periodCarboniferous period
, fifth period of the Paleozoic era of geologic time (see Geologic Timescale, table), from 350 to 290 million years ago. Historical Geology of the Period
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. Uplift of the Appalachians caused the region to be never again inundated by vast marginal seas. Paleoclimatic studies and evidence of glaciers indicate that central Africa was most likely in the polar regions during the early Paleozoic. During the early Paleozoic, the huge continent Gondwanaland had either formed or was forming. By mid-Paleozoic, the collision of N America and Europe produced the Acadian-Caledonian uplifts, and a subduction plate uplifted eastern Australia. By late Paleozoic, continental collisions formed the supercontinent Pangaea and resulted in some of the great mountain chains, including the Appalachians, Urals, and Tasmans. The most noteworthy feature of Paleozoic life is the sudden appearance of nearly all of the invertebrate animal phyla in great abundance at the beginning of the Cambrian. A few primitive fishlike invertebrates, and then vertebrates, appeared in the Cambrian and Ordovician, scorpions in the SilurianSilurian period
[from the Silures, ancient tribe of S Wales, where the period was first studied; named by the British geologist R. I. Murchison], third period of the Paleozoic era of geologic time (see Geologic Timescale, table) lasting from 405 to 435 million years ago.
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 period, land invertebrates and amphibians in the Devonian, land reptiles in the Carboniferous, and marine reptiles in the Permian. All reptiles increased in number and in variety by the late Permian. The plant life of the Paleozoic era reached its climax in the Carboniferous and was much contracted in the Permian.
References in periodicals archive ?
"I think it's the technology that has set us apart from (my parents') Paleozoic Era. I can only imagine what I will be telling my kids about my high school experience that involved such things as computers, text messaging and iPods."
Trilobites first appeared around 521 million years ago and thrived throughout the lower Paleozoic era before going extinct some 250 million years ago or well before the first dinosaurs appeared on the scene.
This guide illustrates preserved Ordovician trilobites from the Paleozoic Era found in Southern Ontario, Canada, as well as neighboring Quebec and New York, including the Ordovician Konservat-Lagerstatten of Beecher's Trilobite Bed and the Walcott-Rust Quarry.
When the team mapped the animals on an evolutionary tree, they found that four of the groups showed a tremendous increase in size during the Permian Period, at the end of the Paleozoic Era. Caseids were the most extreme example of this size increase, says Reisz.
I've visited just one newspaper office since I retired, shortly after the Paleozoic era, and it was the same one in which I had worked a dozen years earlier.
Washington, Feb 8 (ANI): Contrary to conventional belief, a new research shows that the remains of chitin-protein complex-structural materials containing protein and polysaccharide-are present in abundance in fossils of arthropods from the Paleozoic era.
Harriet and I were very pleased with ourselves when we found the perfect remains of a 465-million-year-old trilobite, a kind of big woodlouse that lived on the bottom of the sea, which is where Llandeilo spent the Paleozoic era.
By the way, this all happened during the Paleozoic era, rather than the Mesozoic, as Heaton asserts.
The trilobite existed during the Paleozoic era, 540-250 million years ago.