Early paleozoic era

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 ...

Asia. Asia - Trade, Manufacturing, Agriculture: While the economies of most Asian countries can be characterized as developing, there is enormous variation among them. The continent contains one of the world’s most economically developed countries, Japan, and several that are impoverished, such as Afghanistan, Cambodia, and Nepal.The Paleozoic Era was the era prior to the Mesozoic Era, and the first era of the Phanerozoic Eon ... The era is split into the early Paleozoic (Cambrian to ...The Cambrian Period (/ ˈ k æ m b r i. ə n, ˈ k eɪ m-/ KAM-bree-ən, KAYM-; sometimes symbolized Ꞓ) is the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period 485.4 mya. Its subdivisions, and its base, are ...Feb 2, 2023 · The Ordovician-Silurian Mass Extinction, explained in this World Atlas article, occurred about 443 Ma and killed 80-85% of the animals living on Earth, likely due to climate change. This extinction actually occurred in two major waves. The first started when the climate was cooling in 443 Ma, and the second wave began when the climate began to ... Feb 1, 2021 · Both sites are known for their exposed rocks that date back to the early Paleozoic era. In 2016 and 2017, teams traveled first to Svalbard, then Newfoundland, to collect samples of carbonate muds ... 17 de jun. de 2023 ... This era heralded the first appearance of vascular plants on land and the proliferation of jawed fish and early coral reefs in the oceans. The ...The Paleozoic Era is literally the era of “old life.”. It lasted from 544 to 245 million years ago and is divided into six periods. Major events in each period of the Paleozoic Era are described in Figure below. The era began with a spectacular burst of new life. This is called the Cambrian explosion.

23 de mar. de 2020 ... ... early Paleozoic and lived alongside other fish groups evolving at the same time. Ostracoderm An ostracoderm, the earliest fish. The earliest ...Reconstruction of how the Iapetus Ocean and surrounding continents might have been arranged during the late Ediacaran period. The Iapetus Ocean (/ aɪ ˈ æ p ɪ t ə s /; eye-AP-ih-təs) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago).Feb 15, 2021 · Cambrian Period (540-485 million years) The Cambrian Period is the oldest of the named geological periods of the Paleozoic Era. At the beginning of the Cambrian Period the combination of tectonic forces and erosion of the landscape allowed shallow seas to gradually cover much of North America. Shallow seas covered most of what is now the Great ... The late Paleozoic Era was an interval of major tectonic and climatic changes, including formation of the supercontinent Pangea and the ~60-Myr-long Late Paleozoic Ice Age (LPIA).The early era, known as the Paleozoic, is divided into six periods. It starts with the Cambrian period, followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian. The major event to mark the Ordovician, more than 500 million years ago, was the colonization of land by the ancestors of modern land plants.Asia. Asia - Trade, Manufacturing, Agriculture: While the economies of most Asian countries can be characterized as developing, there is enormous variation among them. The continent contains one of the world’s most economically developed countries, Japan, and several that are impoverished, such as Afghanistan, Cambodia, and Nepal.The Cenozoic Era literally means the era of “modern life.”. It is also called the age of mammals. Mammals took advantage of the extinction of the dinosaurs. They flourished and soon became the dominant animals on Earth. You can learn more about the evolution of mammals during the Cenozoic at the link below. The Cenozoic began 65 million ...The Paleozoic is divided into six periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous(in the U.S., this is divided into the Mississippian and Pennsylvanian Periods), and Permian. Most of these names derive from locations where rocks of these ages were first studied.

The Paleozoic Era Lasted about 2799. You can add all the numbers of the: Permian, Carboniferous, Devonian, Silurian, Ordovician, and the Cambrian. Add all of there numbers of how long each era ...The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. It is the longest of the Phanerozoic eras, lasting from 541 to ...The force of its movement pressed the floor of a Paleozoic sea deep into the earth's mantle, where, in effect, it melted. ... which was abandoned in the early two-thousands, as waste rock began ...During the early part of the Paleozoic Era (approximately 600 million to 350 million years ago), broad, relatively shallow seas repeatedly inundated the Texas Craton and much of North and West Texas. The evidence for these events is found exposed around the Llano Uplift and in far West Texas near Van Horn and El Paso, and also in the subsurface ...What If You Lived in the Paleozoic Era? · THE CAMBRIAN PERIOD · THE ORDOVICIAN PERIOD · THE SILURIAN PERIOD · THE DEVONIAN PERIOD · THE CARBONIFEROUS PERIOD · THE ...The unpublished material from China includes the collection of the macroalgal fossils from the Nantuo Formation. To accommodate the early Paleozoic fossils and to improve the description of macroalgal morphologies required that the list of morphological characters be expanded from 19 in Xiao and Dong (2006) to 30 in the current study.

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Ordovician Period, Paleozoic Era, Phanerozoic Eon [485 Myr - 444 Myr ] The Ordovician and Cambrian Periods are referred to as the "age of invertebrates", with trilobites abundant. In this period, brachiopods became more abundant that the trilobites, but all but one species of them are extinct today.The force of its movement pressed the floor of a Paleozoic sea deep into the earth's mantle, where, in effect, it melted. ... which was abandoned in the early two-thousands, as waste rock began ...Twitter appears to have officially killed off its legacy blue check marks, one of the last remaining vestiges of the pre-Elon Musk era. Twitter appears to have officially killed off its legacy blue check marks, one of the last remaining ves...The Paleozoic witnessed a number of crises in the history of life, including an early Cambrian, a terminal Cambrian, an Ordovician one, a late Devonian one. The era was brought to an end by the terminal Permian extinction, the greatest catastrophe in the history of higher life on Earth (although far milder than the Early Proterozoic Oxygen crisis).Reconstruction of how the Iapetus Ocean and surrounding continents might have been arranged during the late Ediacaran period. The Iapetus Ocean (/ aɪ ˈ æ p ɪ t ə s /; eye-AP-ih-təs) was an ocean that existed in the late Neoproterozoic and early Paleozoic eras of the geologic timescale (between 600 and 400 million years ago). Mar 21, 2023 · The Early Paleozoic refers to a time period in Earth's history from about 541 to 485 million years ago, when marine life was dominant. Over fishing is a human activity that involves excessive fishing and depletion of fish populations, which is not applicable to this time period. Other factors such as over grazing, new predators, and loss of ...

29 ឧសភា 2018 ... The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο), "old" and zoe (ζωη), "life", meaning "ancient life") is the earliest of ...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.Seed plants first appear in the mid-Paleozoic Era, and become the dominant land plants in the Permian Period of the Paleozoic Era. They reproduce by releasing male sex cells (carried in pollen) which land on female sex organs , join with female sex cells, produce a fertilized seed, which can then be released from the plant to land in the soil ...The Early Paleozoic Era ended rather abruptly with the Ice Age of the Late Ordovician, which appeared to be short but severe. This cold snap caused the second ...Comparison of previous estimates on Early Paleozoic richness. The red shading [Sepkoski ()] shows range interpolated presence/absence data partitioned into global stages; the green shading after Alroy shows the sample standardized trend separated into 11-My time bins.Note that the y axis is arbitrary due to different estimates, with …The Ordovician Period. The Ordovician Period lasted almost 45 million years, beginning 488.3 million years ago and ending 443.7 million years ago.* During this period, the area north of the tropics was almost entirely ocean, and most of the world's land was collected into the southern supercontinent Gondwana.Cenozoic Era. The Cenozoic Era (66 million years ago through today) is the "Age of Mammals." Birds and mammals rose in prominence after the extinction of giant reptiles. Common Cenozoic fossils include cat-like carnivores and early horses, as well as ice age fossils like wooly mammoths. Caves can preserve the remains of ice-age animals that ...The Paleogene (alternatively Palaeogene) Period is a unit of geologic time that began 66 and ended 23.03 Ma and comprises the first part of the Cenozoic Era. This period consists of the Paleocene , Eocene and Oligocene Epochs.The Cambrian Period marks an important point in the history of life on Earth; it is the time when most of the major groups of animals first appear in the fossil record. This event is sometimes called the "Cambrian Explosion," because of the relatively short time over which this diversity of forms appears. It was once thought that Cambrian rocks ... Gondwana was an ancient supercontinent that drifted toward the Southern Hemisphere and broke up into Africa, South America, Australia, Antarctica, India and Arabia.View H.GEOL.chapter10.pdf from CIS 188 at University of Michigan, Dearborn. Chapter 10 Early Paleozoic Earth History Relative Geologic Time Scale • The relative geologic time scale has a sequence. Upload to Study. Expert Help. Study Resources. Log in Join. H.GEOL.chapter10.pdf - Chapter 10 Early Paleozoic Earth...An era is the second largest geochronologic time unit and is the equivalent of a chronostratigraphic erathem. [7] [12] As of April 2022 [update] there are currently ten defined eras/erathems, [2] namely the Eoarchean , Paleoarchean , Mesoarchean , Neoarchean , Paleoproterozoic , Mesoproterozoic , Neoproterozoic , Paleozoic , Mesozoic and …

The limited availability of high-resolution tropical climate archives, especially from the Early Paleozoic Era, severely limits our understanding of ITCZ... View Spatial patterns of climate change ...

The 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.During the early Paleozoic era, South America, Africa, Australia, Antarctica, India, and perhaps China comprised the vast southern continent of ________. Gondwanaland. Which type of bacteria thrive in environments that lack free oxygen. anaerobic. Which era of geologic time spans about 88 percent of Earth's history.The basin originated in the late stage of the Early Paleozoic period as an eastward extension part of the Kazakhstan joint plate, which was formed as the result of a large-scale convergence movement in the Paleo-Asian Ocean, its independent prototype was formed in the Early Carboniferous period, and the prototype basin commenced its new growth ...View H.GEOL.chapter10.pdf from CIS 188 at University of Michigan, Dearborn. Chapter 10 Early Paleozoic Earth History Relative Geologic Time Scale • The relative geologic time scale has a sequence ... examine the geologic history of North America - in terms of major transgressions and regressions - rather than a period-by-period chronology ...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 ... 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 ... May 23, 2019 · It is believed that 96% of all species were completely wiped out and the Paleozoic Era came to an end. Sources and Further Reading . Blashfield, Jean F. and Richard P. Jacobs. "When Life Flourished in Ancient Seas: The Early Paleozoic Era." Chicago: Heinemann Library, 2006. ----. "When Life Took Root on Land: The Late Paleozoic Era." Planktonic graptolites became extinct in the Early Devonian, leaving only primitive attached, bushy types to continue until the Pennsylvanian. Silurian and ...

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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 ... B) Mercury and Earth. C) Uranus and Pluto. D) Jupiter and Uranus. E) Neptune and Uranus. B. Abundant fossil evidence did not appear in the geologic record until about ________. A) 5 billion years ago. B) 6 million years ago. C) 540 million years ago. The Paleozoic witnessed a number of crises in the history of life, including an early Cambrian, a terminal Cambrian, an Ordovician one, a late Devonian one. The era was brought to an end by the terminal Permian extinction, the greatest catastrophe in the history of higher life on Earth (although far milder than the Early Proterozoic Oxygen crisis).Mississippian age fossil crinoid, Mammoth Cave National Park, Kentucky. NPS image. Introduction. Geologists in North America use the terms “Mississippian” and “Pennsylvanian” to describe the time period between 358.9 and 298.9 million years ago. In other parts of the world, geologists use a single term and combine these two periods into …Pei F, Zhang HQ, Yan GS (2008) Stratigraphic paleontology research of Henan Province, early paleozoic era, North China. Yellow River Water Resources Press, Zhengzhou, pp 1–302. Google Scholar Pentecost A, Riding R (1986) Calcification in cyanobacteria. In: Leadbeater BC, Riding R (eds) Biomineratization in lower plants and …Oct 30, 2013 · The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon, spanning from roughly 541 to 252.2 million years ago (ICS, 2004). It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to least old): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and ... 1 de jun. de 2005 ... Happenings During the Paleozoic Era (545-248 Million Years Ago) · 545 to 248 million years ago · Geologic periods (divisions) of the Paleozoic: ...The Early Paleozoic ended, rather abruptly, with the short, but apparently severe, Late Ordovician Ice Age. What was the time period of the Paleozoic era? The Paleozoic era, which happened and extended from about 542 million years ago to 251 million years ago, was a time when there were many important changes on Earth.The term ‘Paleozoic’ has been derived from Greek words: palaiosmeaning ‘ancient’ and zoe meaning ‘life’. This era spans around 200 million years from about 542 to 252 M.A. (million years ago), and is the largest one in terms of time-span. It’s the first era of the Phanerozoic Eon, marking the beginning of life on our planet. Book overview. The early history of Earth covers such vast stretches of time that years, centuries, and even millennia become virtually ... ….

28 de ago. de 2019 ... The early Palaeozoic Era records the initial biodiversification of the Phanerozoic. The increase in biodiversity involved drastic changes in ...3 min read. The Cambrian period, part of the Paleozoic era, produced the most intense burst of evolution ever known. The Cambrian Explosion saw an incredible diversity of life emerge, including ... Earth's early atmosphere was made up of hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, and water. 4 billion ... history is divided into three. eras: the Paleozoic Era, the Mesozoic Era, and the Cenozoic Era. Related with Chapter 19 History Of Life Biology:Sep 23, 2023 · Seed plants first appear in the mid-Paleozoic Era, and become the dominant land plants in the Permian Period of the Paleozoic Era. They reproduce by releasing male sex cells (carried in pollen) which land on female sex organs , join with female sex cells, produce a fertilized seed, which can then be released from the plant to land in the soil ... 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 fauna is rare in the Cambrian, becomes more common in the Ordovician, and dominates the rest of the Paleozoic: it remains an important part of the Mesozoic and Cenozoic seas. The Modern fauna is very rare in the Cambro-Ordovician, but continues a stead rise throughout the Phanerozoic: in the post-Paleozoic it is the most abundant ...Era Group News: This is the News-site for the company Era Group on Markets Insider Indices Commodities Currencies Stocks22 de abr. de 2009 ... Paleozoic. There is a little more evidence of the events of the early part of the Paleozoic era in New Zealand. In west Nelson and Fiordland ...Chelicerates also arose in the early Paleozoic and later radiated widely on land. Myriapods are a terrestrial group and gave rise to insects about 400 million years ago (during the Devonian). Insects were already diverse in the Carboniferous Period (359 million to 299 million years ago), and modern orders have gradually originated and then ... Early paleozoic era, Oct 28, 2012 · Ordovician Period. The Cambrian* Period begins the Phanerozoic Eon, the last 542 million years during which fossils with hard parts have existed. It is the first division of the Paleozoic Era (542Ma -251Ma). Marine animals with mineralized skeletons make their first appearance in the shallow seas of the Cambrian, though only "small shelly ... , Oct 30, 2013 · The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon, spanning from roughly 541 to 252.2 million years ago (ICS, 2004). It is the longest of the Phanerozoic eras, and is subdivided into six geologic periods (from oldest to least old): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and ... , The Paleozoic: Warm, shallow seas covered much of the state during the early to middle Paleozoic (Cambrian Devonian). These seas have left behind an extensive record of marine life, including brachiopods, bryozoans, trilobites, corals, bivalves, gastropods, cephalopods, sponges, crinoids, and the scales and teeth of early fishes and sharks., The temperature of a planet is linked with the diversity of life that it can support. MIT geologists have now reconstructed a timeline of the Earth’s temperature during the early Paleozoic era, between 510 and 440 million years ago — a pivotal period when animals became abundant in a previously microbe-dominated world., Silurian Period, in geologic time, the third period of the Paleozoic Era.It began 443.8 million years ago and ended 419.2 million years ago, extending from the close of the Ordovician Period to the beginning of the Devonian …, The early era, known as the Paleozoic, is divided into six periods. It starts with the Cambrian period, followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian. The major event to mark the Ordovician, more than 500 million years ago, was the colonization of land by the ancestors of modern land plants. Fossilized cells, cuticles, and …, The early era, known as the Paleozoic, is divided into six periods. It starts with the Cambrian period, followed by the Ordovician, Silurian, Devonian, Carboniferous, and Permian. The major event to mark the Ordovician, more than 500 million years ago, was the colonization of land by the ancestors of modern land plants. Fossilized cells, cuticles, and …, The Cambrian Period is the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago (mya) to the beginning of the Ordovician Period 485.4 mya. Its subdivisions, and its base, are … See more, The Paleozoic fauna is rare in the Cambrian, becomes more common in the Ordovician, and dominates the rest of the Paleozoic: it remains an important part of the Mesozoic and Cenozoic seas. The Modern fauna is very rare in the Cambro-Ordovician, but continues a stead rise throughout the Phanerozoic: in the post-Paleozoic it is the most abundant ..., The Cambrian Period is the first geological time period of the Paleozoic Era (the "time of ancient life"). This period lasted from 541 million to 485.4 million years ago, or more than 55 million ..., The Early Paleozoic Era Animals first appeared in ancient seas about 600 million years ago. Over the following several hundred million years animal groups diversified and went extinct in response to major global changes in climate, sea level, and mountain building., Paleozoic Era: Devonian. Back. In the course of the Devonian (from 416 to 360 million years ago) the largest Palaeozoic tropical reef in Europe appeared, ..., The Paleozoic (IPA: /ˌpæli.əˈzoʊ.ɪk,-i.oʊ-, ˌpeɪ-/ PAL-ee-ə-ZOH-ik, -⁠ee-oh-, PAY-; or Palaeozoic) Era is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma at the start of the Mesozoic Era. [2], Feb 2, 2023 · The Ordovician-Silurian Mass Extinction, explained in this World Atlas article, occurred about 443 Ma and killed 80-85% of the animals living on Earth, likely due to climate change. This extinction actually occurred in two major waves. The first started when the climate was cooling in 443 Ma, and the second wave began when the climate began to ... , 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., The Paleozoic era was characterized by fluctuations in temperature and in the chemical ... All animal phyla appeared as early as the earliest Paleozoic, (so ..., Mississippian Period (Early Carboniferous) • last widespread Paleozoic carbonate-rich epicontinental sea on N. Amer. craton Kaskaskia Sequence • "Age of Crinoids" • west & mid-continent: thick, shallow water carbonates today: cliff & ridge-forming limestones • east: black shales interbedded with prograding clastics from Acadian highlands , During the Paleozoic Era, there were multi-cellular organisms like trilobites, mollusks, jawless fish, seaweeds and finally, jawed fish, sharks, plants and early amphibians and reptiles., The Cambrian–Ordovician extinction event, also known as the Cambrian-Ordovician boundary event, [1] was an extinction event that occurred approximately 485 million years ago ( mya) in the Paleozoic era of the early Phanerozoic eon. [2] It was preceded by the less-documented (but probably more extensive) End-Botomian mass extinction around …, Early Paleozoic History · consists of the Cambrian, Ordovician, and Silurian periods · 123-million-year span · Gondwana vast continent included South America, ..., The following activities took place between the start and end of the Paleozoic era time scale; I. During the early period of the Paleozoic era (The Cambrian), there existed marine living organisms (phyla). II. During the Paleozoic era, volcanic activity was experienced. III. Lastly, the Paleozoic era was a geologic period that was prone to …, The Cambrian Period: 541 to 485 million years ago What did Earth look like during the Cambrian Period? Sources/Usage: Public Domain. Artist's rendition of life in the Cambrian Sea. For a long time, these fossils were the oldest scientists had found. , By the early Middle Jurassic, the Bangonghu-Nujiang Tethys Ocean and the Mongol-Okhotsk Ocean were subducted northward beneath the Qiangtang terrane and Siberian continent, respectively. These led to the presence of an extensional stress field and the formation of a broader depression basin in the southern WQB during the Middle Jurassic., 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., From the Greek words for “old' and “life” (παλαιό and ζωή respectively), the Paleozoic Era denotes the earliest of three distinctive geologic eras of the ..., During the early Paleozoic, the amount of carbon dioxide in the atmosphere was much greater than it is today. This may have begun to change later, as land plants became more common. As the roots of land plants began to infiltrate rock and soil began to form, carbon dioxide was drawn out of the atmosphere and became trapped in the rock., 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 ..., ABSTRACT. The Paleozoic section became prospective during the early 1970s when the enormous gas reserves in the Permian Khuff reservoirs were delineated in the Gulf and Zagros regions, and oil was discovered in Oman. Since then, frontier exploration has targeted the Paleozoic System throughout the Middle East, driven by …, 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., During the Paleozoic Era, there were multi-cellular organisms like trilobites, mollusks, jawless fish, seaweeds and finally, jawed fish, sharks, plants and early amphibians and reptiles., 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 …, Earth's early atmosphere was made up of hydrogen cyanide, carbon dioxide, carbon monoxide, nitrogen, hydrogen sulfide, and water. 4 billion ... history is divided into three. eras: the Paleozoic Era, the Mesozoic Era, and the Cenozoic Era. Related with Chapter 19 History Of Life Biology:, ... Early Cambrian. The evolution of shelled metazoans is reflected by the appearence of successively more advanced shelly fossils. Trilobites dominate the Cambrian ...