the statements that can be inferred from the Paleozoic era time scale is - Marine organisms existed in the early part of the Paleozoic era.. paleozoic era is sub divided into six age - Cambrian, Ordovician, Silurian, Devonian, Carboniferous and the Permian. the early era of paleozoic period i.e. cambrian era saw the emergence of …The Paleozoic Era. Early Paleozoic events; The formation of Pangea; The Mesozoic and Cenozoic eras. Events in the Mesozoic; The Andean orogeny. The Northern Andes; The …the Palaeozoic, an era of arthropods, amphibians, fishes, and the first life on land; the Mesozoic, which spanned the rise, reign of reptiles, climactic extinction of the non-avian dinosaurs, the evolution of mammals and birds; and. the Cenozoic, which saw the rise of mammals. The Phanerozoic is divided into three eras: the Paleozoic, Mesozoic ...Paleozoic Era, major interval of geologic time that began 538.8 million years ago with the Cambrian explosion, an extraordinary diversification of marine animals, and ended about 252 million years ago with the end-Permian extinction, the greatest extinction event in Earth history. The majorSilurian Period, Interval of geologic time, 443.4–419.2 million years ago, the third period of the Paleozoic Era. The Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes.The Paleozoic era began around 542 million years ago with a massive explosion of life forms. It ended 291 million years later with the extinction of between 90 and 95 percent of life on the planet. Its climate was marked by massive temperature fluctuations as continental masses shifted around the Earth’s surface. ...The Devonian (/ d ɪ ˈ v oʊ n i. ən, d ɛ-/ də-VOH-nee-ən, deh-) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, 419.2 million years ago (), to the beginning of the Carboniferous, 358.9 Ma. It is named after Devon, England, where rocks from this period were first studied.. The first significant …The Paleozoic ("old life") era is characterized by trilobites, the first four-limbed vertebrates, and the origin of land plants. The Mesozoic ("middle life") era represents the "age of dinosaurs," though also is noteworthy for the first appearances of mammals and flowering plants. Gas results of the Silurian show some of the greatest variation in oxygen contents measured in halite during the early Paleozoic. The Mallowa salt (Carribuddy Group) of the Canning Basin (Australia) comes in with a low oxygen content of 12.9% (DM) and comparable 14.3% using the BCM method ( Table 1, Suppl. Fig. S4).Paleozoic definition: designating or of the first geologic era of the Phanerozoic Eon, characterized by the... | Meaning, pronunciation, translations and ...Jun 20, 2013 · The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another.... The Paleozoic Era: Diversification of Plant and Animal Life (The Geologic History of Earth) - ISBN 10: 1615301119 - ISBN 13: 9781615301119 - Britannica ...The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another ...Africa, the second largest continent, covering about one-fifth of the total land surface of Earth. Africa’s total land area is approximately 11,724,000 square miles (30,365,000 square km), and the continent measures about 5,000 miles (8,000 km) from north to south and about 4,600 miles (7,400 km) from east to west.The Ordovician* lasted about 45 million years and saw the transition from very primitive to relatively modern life-forms in the seas. The “Ordovician radiation” which followed the late Cambrian extinctions, lead to a tripling of marine diversity, the greatest increase in the history of life, and giving the highest levels of diversity seen during the …During the Paleozoic Era, which lasted 289 million years, plants and reptiles began moving from the sea to the land. The era has been divided into six periods: Permian, Carboniferous, Devonian, Silurian, Ordovician, and Cambrian. Several times during this era, seas appeared and disappeared in Kansas.The Paleozoic Era (539–252 Ma) is in the Phanerozoic Eon, occurring after the Neoproterozoic Era, and before the Mesozoic Era. It is a time for great plant ...The Carboniferous Period is famous for its vast swamp forests, such as the one depicted here. Such swamps produced the coal from which the term Carboniferous, or "carbon-bearing," is derived. The Carboniferous Period lasted from about 359.2 to 299 million years ago* during the late Paleozoic Era. The term "Carboniferous" comes from England, in ...During the late Paleozoic period, North America was much closer to the equator, and regional elevations in the vicinity of the Ancestral Rockies were much closer to sea level. Figure 1 - Late Paleozoic paleogeography and tectonics of western North America, showing the intracratonic Ancestral Rocky Mountains (dashed pattern) in relation to ...Three tests based on fossil data indicate that high rates of extinction recorded in the penultimate (Guadalupian) stage of the Paleozoic era are not artifacts of a poor fossil record. Instead, they represent an abrupt mass extinction that was one of the largest to occur in the past half billion years. The final mass extinction of the era, which ...The late Palaeozoic era spans from about 419 million years ago to 252 million years ago, and is subdivided into three geological periods in chronological order: the Devonian, Carboniferous and Permian. The late Palaeozoic is characterised by dramatic tectonic movements, global climatic changes and evolutionary novelties both in the ocean and on ...Ordovician Period. Learn more about the time period that took place 488 to 443 million years ago. During the Ordovician period, part of the Paleozoic era, a rich variety of marine life flourished ...South America - Paleozoic, Fossils, Plate Tectonics: The continent’s early Paleozoic rocks depict the breakup of the first supercontinent, an event probably related to the separation of eastern North America from the pre-Andean basement rocks of western South America. As a result of that separation, a series of passive continental margins developed along the western side of the continent ...The Paleozoic saw periods of intense mountain building, extensive glaciations, widespread shallow seas, and the continued buildup of material onto the continental cratons, building the continents into shapes resembling what you see today. The construction of continents The history of each continent is told in its rocks.The Paleozoic era culminated 251.9 million years ago in the most severe mass extinction recorded in the geologic record. Known as the "great dying," this event saw the loss of up to 96% of all ...Based on these maps, the proto-type basin and tectono-paleogeographic features of the Tarim basin during the Late Paleozoic are illustrated. The Devonian to Permian is an important period of terranes/island-arcs accretion and oceanic closure along the periphery of the Tarim block, and a critical period when the polarity of Tarim basin (orientation of …The North Qinling orogen, central China, formed above an ancient ocean-continent subduction zone and contains widespread early-Paleozoic I-type granites. Previous studies have shown that the mantle wedge beneath the north Qinling unit was significantly metasomatized and isotopically enriched relative to the lower crust in the …Cenozoic (66 million years ago until today) means ‘recent life.’ During this era, plants and animals look most like those on Earth today. Periods of the Cenozoic Era are split into even smaller parts known as Epochs, so you will see even more signposts in this Era. Cenozoic signposts are colored yellow.The mountains formed by the Alleghanian orogeny were once rugged and high during the Mesozoic and late Paleozoic, but in our time are now eroded into only a small remnant: the heavily eroded hills of the Piedmont. Sediments that were carried eastward formed the coastal plain and part of the continental shelf.8.1 The Geological Time Scale. William “Strata” Smith worked as a surveyor in the coal-mining and canal-building industries in southwestern England in the late 1700s and early 1800s. While doing his work, he had many opportunities to look at the Paleozoic and Mesozoic sedimentary rocks of the region, and he did so in a way that few had done ...Gas results of the Silurian show some of the greatest variation in oxygen contents measured in halite during the early Paleozoic. The Mallowa salt (Carribuddy Group) of the Canning Basin (Australia) comes in with a low oxygen content of 12.9% (DM) and comparable 14.3% using the BCM method ( Table 1, Suppl. Fig. S4).The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another....The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another....The Paleozoic Era, which ran from 541 million to 251.9 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another....Oct 6, 2023 · Cambrian Period, earliest time division of the Paleozoic Era and Phanerozoic Eon, lasting from 538.8 million to 485.4 million years ago. The Cambrian System, named by English geologist Adam Sedgwick for slaty rocks in southern Wales and southwestern England, contains the earliest record of abundant and varied life-forms. Silurian Period, Interval of geologic time, 443.4–419.2 million years ago, the third period of the Paleozoic Era. The Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes.The Paleozoic era culminated 251.9 million years ago in the most severe mass extinction recorded in the geologic record. Known as the "great dying," this event saw the loss of up to 96% of all ...Mesozoic. Mesozoic (252-66 million years ago) means 'middle life' and this is the time of the dinosaurs. This era includes the Triassic, Jurassic, and Cretaceous Periods, names that may be familiar to you. It ended with a massive meteorite impact that caused a mass extinction, wiping out the dinosaurs and up to 80% of life on Earth.The period, and the Paleozoic era, came to a calamitous close 251 million years ago, marking a biological dividing line that few animals crossed.Throughout the Palaeozoic era, about 540 to 250 million years ago, plants colonized land and rapidly diversified. An analysis of the palaeontologic record shows that this diversification ...Although the early Paleozoic was ruled by invertebrates, the development of skeletal features had also begun. The evolutionary story of chordates—animals with a nerve chord (which later includes animals with a backbone, or vertebrates)—is missing in the geologic fossil record because there were no hard skeletal parts to preserve.Gymnosperm - Evolution, Paleobotany, Reproduction: Gymnosperms were the first seed plants to have evolved. The extinct Progymnospermophyta is thought to be ancestral to seed plants. The earliest recognized group of gymnospermous seed plants are of the extinct Pteridospermophyta (pteridosperms or seed ferns), which originated in the Devonian and …Introduction. The Paleozoic Era was a major interval of geologic time. It began 541 million years ago with a rapid expansion of life-forms and ended 252 million years ago with the largest mass extinction in Earth’s history. The Paleozoic was the first of the three major eras of the Phanerozoic Eon; this is reflected in its name: paleozoic is ... The Paleozoic Era, named after the Greek word for “ancient life” ( Sedgwick, 1838 ), is the earliest and longest-lasting era of the Phanerozoic Eon.May 23, 2019 · Periods of the Paleozoic Era. The Paleozoic Era begins after the Pre-Cambrian about 297 million years ago and ends with the start of the Mesozoic period about 250 million years ago. Each major era on the Geologic Time Scale has been further broken down into periods that are defined by the type of life that evolved during that span of time. Oct 20, 2023 · Cenozoic Era, third of the major eras of Earth’s history, beginning about 66 million years ago and extending to the present. It was the interval of time during which the continents assumed their modern configuration and geographic positions and during which Earth’s flora and fauna evolved toward those of the present. Trilobites (/ ˈ t r aɪ l ə ˌ b aɪ t s, ˈ t r ɪ l ə-/; meaning "three lobes") are extinct marine arthropods that form the class Trilobita.Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period) and they flourished throughout the lower …Silurian Period, Interval of geologic time, 443.4–419.2 million years ago, the third period of the Paleozoic Era. The Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes.The Ordovician* lasted about 45 million years and saw the transition from very primitive to relatively modern life-forms in the seas. The “Ordovician radiation” which followed the late Cambrian extinctions, lead to a tripling of marine diversity, the greatest increase in the history of life, and giving the highest levels of diversity seen during the Paleozoic Era.The Ordovician* lasted about 45 million years and saw the transition from very primitive to relatively modern life-forms in the seas. The “Ordovician radiation” which followed the late Cambrian extinctions, lead to a tripling of marine diversity, the greatest increase in the history of life, and giving the highest levels of diversity seen during the …The period, and the Paleozoic era, came to a calamitous close 251 million years ago, marking a biological dividing line that few animals crossed.The Paleozoic, the Mesozoic and the Cenozoic are the 3 Eras of the Phanerozoic Eon.The Paleozoic Era occurred between 542 and 251 million years ago. It lasted 291 million years. It was made up of ...Scientists know that dragonflies with wing spans as wide as a hawk’s and cockroaches big enough to take on house cats lived during the Paleozoic era (245-570 million years ago). At the same time, mammoth millipedes longer than a human leg skittered across prehistoric soil. Hundreds of different huge species evolved during the late …- jawless fish (agnathans), which had been known only by fossilized scales and bony plates since the Late Cambrian, became common in the middle Paleozoic; they ...Paleozoic Era. The Paleozoic era begins with the Cambrian radiation, a time of great growth in the number of different kinds of animals in the oceans. It ends with the greatest extinction in the history of life. Other major extinction events occurred at the end of the Ordovician Period and near the end of the Devonian Period. The Paleozoic Era ...Echinoids are marine animals belonging to the phylum Echinodermata and the class Echinoidea. They have a hard shell (referred to as a test) covered with small knobs (tubercles) to which spines are attached in living echinoids. The test and spines are the parts normally found as fossils. Simplified cross section through a living echinoid.The ovules and pollen organs were separate reproductive units, and wind may have been the most common agent of pollen transfer. Some seed ferns of the Paleozoic Era (about 541 million to 252.2 million years ago) contained pollen grains that were much too large to be effectively dispersed by the wind. These plants probably depended on insects to ...With the Geological History of Saryarqa app, you can learn about: - such specifications of Saryarka as administrative position, relief, hydrological relation, climate; - geological …The period, and the Paleozoic era, came to a calamitous close 251 million years ago, marking a biological dividing line that few animals crossed.The early Paleozoic high-pressure and high-temperature metamorphism, characterized by clockwise P–T paths with pressures up to 14 kbars, cannot be readily explained by the intraplate orogenic model, as the model does not provide a mechanism for burial of supracrustal rocks to over 45 km depth and for its later exhumation.1991. The Mesozoic Era [3] is the second-to-last era of Earth's geological history, lasting from about 252 to 66 million years ago, comprising the Triassic, Jurassic and Cretaceous Periods. It is characterized by the dominance of archosaurian reptiles, such as the dinosaurs; an abundance of gymnosperms, (such as ginkgoales, bennettitales) and ...Sep 1, 2023 · The Paleozoic Era, named after the Greek word for “ancient life” (Sedgwick, 1838), is the earliest and longest-lasting era of the Phanerozoic Eon.It began with the Cambrian explosion at ∼538.8 Ma, a major diversification of marine animals, and ended at 251.9 Ma with the end-Permian extinction, the greatest mass extinction in Earth's history (Fig. 1). The Paleozoic Era occurred from about 541 million years ago to about 252 million years ago. The meaning of the word Paleozoic derives from the Greek Word palaios – which means “ancient” and the Greek word zoe – which means “life.”. Which is an apt name for this period in Earth history because this is when life really began to take ... The Paleozoic Era occurred from about 541 million years ago to about 252 million years ago. The meaning of the word Paleozoic derives from the Greek Word palaios – which means “ancient” and the Greek word zoe – which means “life.”. Which is an apt name for this period in Earth history because this is when life really began to take ...Permian–Triassic boundary at Frazer Beach in New South Wales, with the End Permian extinction event located just above the coal layer. The Permian–Triassic (P–T, P–Tr) extinction event (PTME), also known as the Late Permian extinction event, the Latest Permian extinction event, the End-Permian extinction event, and colloquially as the Great …The supercontinent cycle is the quasi-periodic aggregation and dispersal of Earth 's continental crust. There are varying opinions as to whether the amount of continental crust is increasing, decreasing, or staying about the same, but it is agreed that the Earth's crust is constantly being reconfigured. One complete supercontinent cycle is said ...Many Paleozoic predators became extinct by the end of the Permian, with few groups surviving; however, some predators rebounded rapidly after the end-Permian mass extinction (Walker and Brett 2002). According to these authors, during the Middle Triassic, a number of new predator guilds appeared; these include lobsters having …Carboniferous Period. This time period took place 359 to 299 million years ago. The Carboniferous period, part of the late Paleozoic era, takes its name from large underground coal deposits that ...Laurentia, also called the North American craton. Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America.Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and also the …Study with Quizlet and memorize flashcards containing terms like Dikes, cells, veins, and fractures are features that can be used in the principle of _____ to determine the relative age of geologic events., identify possible causes of the great dying, the mass extinction at the end of the Paleozoic., Match the principle of relative dating with its definition and more.Oct 3, 2008 · Sea levels have been determined for most of the Paleozoic Era (542 to 251 million years ago), but an integrated history of sea levels has remained unrealized. We reconstructed a history of sea-level fluctuations for the entire Paleozoic by using stratigraphic sections from pericratonic and cratonic basins. Evaluation of the timing and amplitude ... Africa, the second largest continent, covering about one-fifth of the total land surface of Earth. Africa’s total land area is approximately 11,724,000 square miles (30,365,000 square km), and the continent measures about 5,000 miles (8,000 km) from north to south and about 4,600 miles (7,400 km) from east to west.Geological history. The oldest rocks in California date back 1.8 billion years to the Proterozoic and are found in the San Gabriel Mountains, San Bernardino Mountains, and Mojave Desert. The rocks of eastern California formed a shallow continental shelf, with massive deposition of limestone during the Paleozoic, and sediments from this time are ...8.6: Paleozoic. Figure 8.6.1 8.6. 1: The trilobites had a hard exoskeleton and were an early arthropod, the same group that includes modern insects, crustaceans, and arachnids. The Phanerozoic eon is the most recent eon and represents time in which fossils are common, 541 million years ago to today.Cambrian Period, earliest time division of the Paleozoic Era and Phanerozoic Eon, lasting from 538.8 million to 485.4 million years ago. The Cambrian System, named by English geologist Adam Sedgwick for slaty rocks in southern Wales and southwestern England, contains the earliest record of abundant and varied life-forms.Echinoids are marine animals belonging to the phylum Echinodermata and the class Echinoidea. They have a hard shell (referred to as a test) covered with small knobs (tubercles) to which spines are attached in living echinoids. The test and spines are the parts normally found as fossils. Simplified cross section through a living echinoid.Paleozoic Mesozoic Cenozoic. The Paleozoic does not include the. Ordovician Jurassic Mississippian Permian. The _____ was an era dominated by the dinosaurs. Precambrian Paleozoic Mesozoic Cenozoic. The boundaries between _____ seem to coincide with major changes in the life forms present on Earth. Precambrian systems eras epochsThe Paleozoic is a time in Earth's history when active complex life forms evolved, took their first foothold on dry land, and when the forerunners of all multicellular life on Earth began to diversify. There are six periods in the Paleozoic era: Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian.Laurentia, also called the North American craton. Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America.Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and also the …Ordovician Period. Learn more about the time period that took place 488 to 443 million years ago. During the Ordovician period, part of the Paleozoic era, a rich variety of marine life flourished ...
The Permian Period was the final period of the Paleozoic Era. Lasting from 298.9 million to 251.9 million years ago, it followed the Carboniferous Period and preceded the Triassic Period. By the .... Fossilized crinoid
Oct 4, 2018 · A recent study by Edwards et al. 55, has used this equation to estimate atmospheric oxygen concentrations in the early Paleozoic from the δ 13 C record in organic C and carbonates, using values ... SELECT TWO. -It was a series of impacts that occurred well after the planets formed. -It may have bought a significant amount of water to Earth's surface. (NOT: -It helped form the first ocean basins and continents. -It remelted planet Earth into magma again. -It was the highest period of impacts in Earth's history.The Paleozoic Era. The Cambrian Period: Following the Precambrian mass extinction, there was an explosion of new kinds of organisms in the Cambrian Period (544-505 million years ago).Many types of primitive animals called sponges evolved. Small ocean invertebrates called trilobites became abundant.. Two representatives of more than fifty modern animal phyla from the Cambrian explosion are ...Permian–Triassic boundary at Frazer Beach in New South Wales, with the End Permian extinction event located just above the coal layer. The Permian–Triassic (P–T, P–Tr) extinction event (PTME), also known as the Late Permian extinction event, the Latest Permian extinction event, the End-Permian extinction event, and colloquially as the Great …The Precambrian (/ p r i ˈ k æ m b r i. ə n,-ˈ k eɪ m-/ pree-KAM-bree-ən, -KAYM-; or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the Phanerozoic Eon, which is named after Cambria, the …Mesozoic Era, second of Earth’s three major geologic eras of Phanerozoic time. Its name is derived from the Greek term for “middle life.” The Mesozoic Era began 252.2 million years ago, following the conclusion of the Paleozoic Era, and ended 66 million years ago, at the dawn of the Cenozoic Era.A cratonic sequence (also known as megasequence, Sloss sequence or supersequence) in geology is a very large-scale lithostratigraphic sequence in the rock record that represents a complete cycle of marine transgression and regression on a craton (block of continental crust) over geologic time. They are geologic evidence of relative sea level ...The Paleozoic Era. The Cambrian Period: Following the Precambrian mass extinction, there was an explosion of new kinds of organisms in the Cambrian Period (544-505 million years ago).Many types of primitive animals called sponges evolved. Small ocean invertebrates called trilobites became abundant.. Two representatives of more than fifty modern animal phyla from the Cambrian explosion are ...The Paleozoic Era: Diversification of Plant and Animal Life (The Geologic History of Earth) - ISBN 10: 1615301119 - ISBN 13: 9781615301119 - Britannica ...The Big Picture. The geologic history of the northeastern United States is a story of active mountain building and the quieter processes of weathering, erosion, and deposition of sediments.The Northeast is at the edge of a continent (North America), but in the middle of a plate (the North American plate), which extends from the mid-Atlantic …In earliest Paleozoic time (roughly 540 million years ago), North America was situated on the equator, and Minnesota was a low-lying, mostly flat area. Although the climate was probably tropical, land plants had not yet evolved so the land surface was barren except for some primitive algae and bacteria. Sea level began to rise much higher than ... Paleozoic (Smithsonian Institution) Viewed from space, the Paleozoic Earth would be a foreign world. During this era, seas flooded the continents and receded several times. During the early Paleozoic three small continents— Laurentia, Siberia, and Baltica—split apart from the rest of the supercontinent Gondwana and formed the Lapetus Ocean ...This indicates that the last eurypterids died either in the catastrophic extinction event at its end or at some point shortly before it. This extinction event, the Permian–Triassic extinction event, is the most devastating mass extinction recorded, and rendered many other successful Paleozoic groups, such as the trilobites, extinct.Ordovician Period, in geologic time, the second period of the Paleozoic Era. It began 485.4 million years ago and ended 443.8 million years ago. The interval was a time of intense diversification (an increase in the number of species) of marine animal life in what became known as the Ordovician radiation.Paleozoic 252 to 541 million years ago. During most of the Paleozoic shallow tropical seas covered Illinois and Wisconsin. These seas left behind thick layers of sedimentary rocks filled with the ancient life that lived in these seas. Cambrian - 485 to 541 million years agoOct 3, 2008 · Sea levels have been determined for most of the Paleozoic Era (542 to 251 million years ago), but an integrated history of sea levels has remained unrealized. We reconstructed a history of sea-level fluctuations for the entire Paleozoic by using stratigraphic sections from pericratonic and cratonic basins. Evaluation of the timing and amplitude ... The end of the Precambrian Time period came at the beginning of the Cambrian Period of the Phanerozoic Eon and Paleozoic Era. This time of great biological diversity and rapid increase in organism complexity is known as the Cambrian Explosion. The end of the Precambrian Time marked the start of the more quickly progressing …The Paleozoic Era occurred from about 541 million years ago to about 252 million years ago. The meaning of the word Paleozoic derives from the Greek Word palaios – which means “ancient” and the Greek word zoe – which means “life.”. Which is an apt name for this period in Earth history because this is when life really began to take ...Ordovician Period. Learn more about the time period that took place 488 to 443 million years ago. During the Ordovician period, part of the Paleozoic era, a rich variety of marine life flourished ...- jawless fish (agnathans), which had been known only by fossilized scales and bony plates since the Late Cambrian, became common in the middle Paleozoic; they ...The Paleozoic Era occurred from about 541 million years ago to about 252 million years ago. The meaning of the word Paleozoic derives from the Greek Word palaios – which ….