What is the first period of the paleozoic era - Paleozoic (541-252 million years ago) means ‘ancient life.’ The oldest animals on Earth appeared just before the start of this era in the Ediacaran Period, but scientists had not yet discovered them when the geologic …

 
The Paleozoic is bracketed by two of the most important events in the history of animal life. At its beginning, multicelled animals underwent a dramatic "explosion" in diversity, and almost all living animal phyla appeared within a few millions of years. At the other end of the Paleozoic, the largest mass extinction in history wiped out approximately 90% of all marine animal species.. Jones softball

Jul 7, 2022 · The Paleozoic Era (542–251 mya) Advertisement. The Cambrian Period saw the explosion of new kinds of invertebrate animals in the oceans, including trilobites (Figure 2), primitive kinds of shellfish, including brachiopods and molluscs, and other groups of invertebrates that failed to survive the end of this period. The Permian period lasted from 299 to 251 million years ago* and was the last period of the Paleozoic Era. The distinction between the Paleozoic and the Mesozoic is made at the end of the Permian in recognition of the largest mass extinction recorded in the history of life on Earth. It affected many groups of organisms in many different ...b. meteorite crashing into Earth. c. the sudden increase in a particular gas in the atmosphere of the entire planet. d. all of the above. d. The end of the Paleozoic Era was signaled by ____. a. the development of humans. b. mass extinction of land and sea animals. c. the development of organisms with hard parts. d. both a and b.The beginning of the Paleozoic Era is marked by the first appearance of hard body parts like shells, spikes, teeth, and scales; and the appearance in the rock record of most animal phyla known today. That is, most basic animal body plans appeared in the rock record during the Cambrian Period .The last period of the Paleozoic era was the Permian, and the first period of the Mesozoic era was the Triassic; hence the extinction event (the biggest extinction event in the earth's history ...The Ordovician period was the first time in which fish existed. It was the predecessor period to the Devonian era. ... These fish evolved during the Paleozoic era and were widespread in the water ...Paleozoic Era. During the earliest Paleozoic Era, the continent that would later become North America straddled the equator. ... During the middle Ordovician Period (about 480-440 million years ago), a change in plate motions set the stage for the first Paleozoic mountain building event (Taconic orogeny) in North America. The once quiet …Progressing from the oldest to the current, the four major eras of Earth’s geological history are Precambrian, Paleozoic, Mesozoic and Cenozoic. The current GTS era, the Cenozoic Era, began 65.5 million years ago.That is, Gondwana existed both before the supercontinent Pangaea formed near the end of the Paleozoic era (roughly 350 to 260 million years ago), and it remained together, with some changes, after Pangaea broke up during the Triassic and Jurassic periods of the Mesozoic (with this rifting beginning about 208 million years ago). Gondwana itself …Cambrian period is the first period of Paleozoic era.In this period,Cambrian explosion has occured.The life has evolved very quickly and formed variety of ...Paleozoic crinoids. Crinoids first appeared in the fossil record during the Tremadocian Stage (485.4 – 477.7 million years ago) of the Ordovician and became diverse during the Great Ordovician Biodiversity Event—a time when many clades of early life diversified. ... reaching their maximum fossil diversity during the Early …The Permian ( / ˈpɜːrmi.ən / PUR-mee-ən) [4] is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the last period of the Paleozoic Era; the following Triassic Period belongs to the ...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.What are the periods of the Paleozoic Era from oldest to youngest? The major divisions of the Paleozoic Era, from oldest to youngest, are the Cambrian (541 million to 485.4 million years ago), Ordovician (485.4 million to 443.8 million years ago), Silurian (443.8 million to 419.2 million years ago), Devonian (419.2 million to 358.9 million ...Study with Quizlet and memorize flashcards containing terms like 1. When did the Paleozoic Era begin and end? (Give actual dates from Geologic time Scale), 2. List the 7 periods of the Paleozoic Era in order, spelled correctly, from oldest to youngest:, 3. What is the Carboniferous? and more.Paleozoic (541-252 million years ago) means ‘ancient life.’ The oldest animals on Earth appeared just before the start of this era in the Ediacaran Period, but scientists had not yet discovered them when the geologic timescale was made. What are the periods of the Paleozoic Era from oldest to youngest? The major divisions of the Paleozoic Era, from oldest to youngest, are the Cambrian (541 million to 485.4 million years ago), Ordovician (485.4 million to 443.8 million years ago), Silurian (443.8 million to 419.2 million years ago), Devonian (419.2 million to 358.9 million ...Fish evolved, and plants and animals started the move from the ocean onto dry land. Most plants and animals from this time are extinct in our modern world, which is why the Paleozoic is named for “ancient life." The 6 periods in this era are described below, as shown in the "Fossils Tell a Scientific Story" exhibit in the Hall of Evolution.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 in between. Precambrian Time. Learn more about the period that occurred 4.5 billion to 542 million years ago. Precambrian time covers the vast bulk of the Earth's history, starting with the planet's creation ...The geologic time scale is a way of representing deep time based on events that have occurred throughout Earth's history, a time span of about 4.54 ± 0.05 Ga (4.54 billion years). It chronologically organises strata, and subsequently time, by observing fundamental changes in stratigraphy that correspond to major geological or paleontological events.Study with Quizlet and memorize flashcards containing terms like 1. When did the Paleozoic Era begin and end? (Give actual dates from Geologic time Scale), 2. List the 7 periods of the Paleozoic Era in order, spelled correctly, from oldest to youngest:, 3.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. what is the first period of the paleozoic era. marine. variety of_____ life-forms appeared during this period. warm, shallow waters. There was an explosion of Cambrian life due to_____ trilobites _____, marine invertebrates, are the most common Cambrian invertebrates. index fossils. trilobites are called_____ and are used to date rocks to the …Study with Quizlet and memorize flashcards containing terms like In class, we learned that the Paleozoic Era is the time of oldor ancient life. In order from earliest to latest, the periodsof the Paleozoic Era are: Cambrian, Ordovician, Silurian,Devonian, Carboniferous, and Permian. The CambrianPeriod was named after Cambria, the Latin name for …For example, the Silurian and Ordovician are both geological periods in the Paleozoic Era, but the Silurian Period spanned 443 million years while the Ordovician Period lasted only 45 million years. ... The Paleozoic era spanned from 540 to 252 million years ago (mya) and represents the first era of diverse, complex life on Earth. The name Paleozoic means …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. When vertebrate fossils do show up in the fossil record, they are already full-fledged fish with backbones. And due to ...Oct 30, 2013 · The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian Period witnessed the most rapid and widespread diversification of life in Earth’s history, known as the Cambrian explosion, in which most modern phyla first appeared. Fish, arthropods, amphibians and reptiles all evolved during the Paleozoic. Life During the Paleozoic. 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.The first dragonflies had 29" wingspans and the first cockroaches were four inches long. The end of the Paleozoic Era is the Permian Period, sometimes called the "Age of Amphibians" Amphibians and reptiles are the dominant fauna and gymnosperms the dominant plant life. The Permian ends with a large mass extinction, perhaps caused by glaciation ...ICS Carboniferous timeline. The Carboniferous was the fifth geological period of the Paleozoic era, extending from approximately 358.9 million to 298.9 million ...After the Permian Extinction wiped out over 95% of ocean-dwelling species and 70% of land species, the new Mesozoic Era began about 250 million years ago. The first period of the era was called the Triassic Period. The first big change was seen in the types of plants that dominated the land. Most of the species of plants that survived the ...The fossils found in this period underline that this period was the origin of reptiles. Amphibians dominate this period, thus it is referred to as the Age of amphibians. > Ordovician: This period was around 500-505 million years ago. In this period, the first vertebrates, especially jawless fishes, were found. Marine algae were abundant.The Paleozoic era was dominated by marine organisms, but by the middle of the era, plants and animals had evolved to live and reproduce on land, including amphibians and reptiles. Fish evolved jaws and fins evolved into limbs. Lungs evolved and life emerged from the sea onto land to become the first four-legged tetrapods, amphibians.The Paleozoic is subdivided into six geologic periods : The Paleozoic Era is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago , it succeeds the Neoproterozoic and ends 251.9 Ma at the start of the Mesozoic Era.The Paleozoic is bracketed by two of the most important events in the history of animal life. At its beginning, multicelled animals underwent a dramatic "explosion" in diversity, and almost all living animal phyla appeared within a few millions of years. At the other end of the Paleozoic, the largest mass extinction in history wiped out approximately 90% of all marine animal species.How long should periods last? How are pads, tampons, and menstrual cups used? Find answers to these questions and more.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. Cambrian Period The Paleozoic era occurred 542 to 250 million years ago. It is divided into six periods of time and the last two saw the development of the largest insects. These were known as the Carboniferous period (360 to 300 million years ago) and the Permian period (300 to 250 million years ago). Atmospheric oxygen is the single most limiting factor for ...A. Produced oxygen. Which of the flowing describes how Earth's atmosphere changed during Precambrian time. C. The amount of oxygen increased. Which of the following is true about stromatolites. B. They are layered mounds of deposits made by Precambrian algae. What was the first period of the Paleozoic era. B. Cambrian.Generally, the eras used to describe the modern Earth are the Quaternary geological era and the Cenozoic evolutionary era. In the future, there may also be a historical era that the current time period, the 21st century, will belong to.This led to the widespread distribution of tetrapods during the early Carboniferous period. The Paleozoic Era and the Evolution of Vertebrates. The climate and geography of Earth was vastly different during the Paleozoic Era, when vertebrates arose, as compared to today. The Paleozoic spanned from approximately 542 to 251 million years ago.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 great radiation of modern mammals began in the mid-Cenozoic era, in the late Cretaceous period, approximately 100 million years ago. More rapid evolution of larger body sized mammals did not begin until the mid-Cenozoic, beginning about 65 million years ago during the Paleocene epoch of the Tertiary. 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 era where complex multi-cellular life appeared and began to thrive on Earth, the Paleozoic Era encompasses a period of time around 542 to 251 million years ago, with separate periods dividing the era further.Study the diagram of the geologic time scale. A time scale measured in Millions of years ago or M Y A. Cenozoic Era includes Quaternary Period, 0 to 1.6 M Y A, and Tertiary Period, 1.6 to 66.4 M Y A. Mesozoic Era includes Cretaceous Period, 66.4 to 144 M Y A, Jurassic Period, 144 to 208 M Y A, Triassic Period, 208 to 245 M Y A. …Bookshelves. Introductory and General Biology. Introductory Biology (CK-12) 5: Evolution. 5.9: Life During the Paleozoic.The Phanerozoic Eon is a period of geological history that spans 542 million years and is typically subdivided into three eras. These eras are: Paleozoic Era: 542 to 251 million years ago. Mesozoic Era: 251 to 65 million years ago. Cenozoic Era: 65 million years ago to present. Mesozoic. The dinosaurs and the mammals appeared during the ... Geologic Time Scale. Today, the geologic time scale is divided into major chunks of time called eons. Eons may be further divided into smaller chunks called eras, and each era is divided into periods. Figure 12.1 shows you what the geologic time scale looks like. We now live in the Phanerozoic eon, the Cenozoic era, and the Quarternary period.28 Apr 2023 ... Also noteworthy in this period is the first appearance of ... Part of a series of articles titled Geologic Time Periods in the Paleozoic Era.Paleozoic Era 542 to 151 million years ago. This is the era in which much change had occurred. The first hard parts species started to appear such as primitive fish, coral, plant life, Vertebrate animals form along with arachnids, and wingless insects. During the end of the Paleozoic Era, the Permian Period begins. The Mesozoic Era (252 to 66 million years ago) The Mesozoic Era is the geological period between 252 million and 66 million years ago and is subdivided into three epochs: the Triassic, Jurassic, and Cretaceous. The Mesozoic Era is often referred to as the Age of Reptiles because most dinosaurs lived there.The era of the middle life, a time of many changes.on earth. c. humans d. technology Paleozoic c. Cenozoic A 4. The largest division of the geologic time scale is the: c. Period C_ 5. During which era were the first land plants formed? а. b. Mesozoic d. holozoic a. Eon b. Era d. Epoch b. Pre-Cambrian C_ 6. Which geologic event occurred during ...Geological time has been divided into four eons: Hadean (4570 to 4850 Ma), Archean (3850 to 2500 Ma), Proterozoic (2500 to 540 Ma), and Phanerozoic (540 Ma to present). As shown in Figure 8.1.2, the first three of these represent almost 90% of Earth’s history. The last one, the Phanerozoic (meaning “visible life”), is the time that we are ...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. The Paleozoic is subdivided into six geologic periods ...The discovery reveals oxygen changes at the seafloor across nearly 120 million years of the early Paleozoic era, a time that fostered the most rapid development and diversification of complex ...Terms in this set (62) 1. When did the Paleozoic Era begin and end? (Give actual dates from Geologic time Scale) 541 Ma - 252 Ma. 2. List the 7 periods of the Paleozoic Era in order, spelled correctly, from oldest to youngest: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian. 3.The Phanerozoic Eon is a period of geological history that spans 542 million years and is typically subdivided into three eras. These eras are: Paleozoic Era: 542 to 251 million years ago. Mesozoic Era: 251 to 65 million years ago. Cenozoic Era: 65 million years ago to present. Mesozoic. The dinosaurs and the mammals appeared during the ... The Devonian, part of the Paleozoic era, is otherwise known as the Age of Fishes, as it spawned a remarkable variety of fish. ... By the end of the period the first ferns, horsetails, and seed ...Colwell, a former curator at the Denver Museum of Nature & Science, divides humanity’s association with “stuff” into three periods. At the start of the first (and by far …Devonian Period, in geologic time, an interval of the Paleozoic Era that follows the Silurian Period and precedes the Carboniferous Period, spanning between about 419.2 million and 358.9 million years ago.The Devonian Period is sometimes called the "Age of Fishes" because of the diverse, abundant, and, in some cases, bizarre types of these creatures that swam Devonian seas.This geological era spans from 66 mya to the present day. The human species is an example of a Cenozoic era mammal species. Although the ancestors of early mammals first evolved in the late Paleozoic era and coexisted with dinosaurs during the Mesozoic era, this group did not flourish until the Cenozoic era that began 66 mya.First Reptile . Depending on how strictly you define the term, there are two prime candidates for the first-ever reptile. One is the early Carboniferous Period (about 350 million years ago) Westlothiana, from Europe, which laid leathery eggs but otherwise had an amphibian anatomy, especially pertaining to its wrists and skull.The other, more widely …Devonian Period, Interval of geologic time, 419.2–358.9 million years ago. It was the fourth period of the Paleozoic Era. During the Devonian a giant continent was situated in the Southern Hemisphere (see Gondwana), and other landmasses were located in the equatorial regions. Siberia was separated from Europe by a broad ocean, and North ... The Paleozoic Era. 543 to 248 Million Years Ago. The Paleozoic is bracketed by two of the most important events in the history of animal life. At its beginning, multicelled animals underwent a dramatic "explosion" in diversity, and almost all living animal phyla appeared within a few millions of years. At the other end of the Paleozoic, the largest mass extinction in history wiped out ...The Permian period was, literally, a time of beginnings and endings. It was during the Permian that the strange therapsids, or "mammal-like reptiles," first appeared--and a population of therapsids went on to spawn the very first mammals of the ensuing Triassic period. However, the end of the Permian witnessed the most severe mass …The Paleozoic era was dominated by marine organisms, but by the middle of the era, plants and animals had evolved to live and reproduce on land, including amphibians and reptiles. Fish evolved jaws and fins evolved into limbs. Lungs evolved and life emerged from the sea onto land to become the first four-legged tetrapods, amphibians. The Second era of the World. The time period between the Precambrian and Mesozoic periods that lasted for nearly 340 million years is the Paleozoic era. This era is divided into several periods like the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. The Cambrian period was the first part of this era which started ...The Paleozoic is subdivided into six geologic periods : The Paleozoic Era is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago , it succeeds the Neoproterozoic and ends 251.9 Ma at the start of the Mesozoic Era. Terms in this set (62) 1. When did the Paleozoic Era begin and end? (Give actual dates from Geologic time Scale) 541 Ma - 252 Ma. 2. List the 7 periods of the Paleozoic Era in order, spelled correctly, from oldest to youngest: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian. 3.Jun 11, 2018 · The Paleozoic Era spanned that period of geologic time during which the evolution of the first invertebrates, vertebrates, terrestrial (land-based) plants, bony fish, reptiles, insects, etc. took place. The end of the Paleozoic Era (approximately 245 mya) marks the largest mass extinction of species in Earth's history. Devonian Period, in geologic time, an interval of the Paleozoic Era that follows the Silurian Period and precedes the Carboniferous Period, spanning between about 419.2 million and 358.9 million years ago.The Devonian Period is sometimes called the "Age of Fishes" because of the diverse, abundant, and, in some cases, bizarre types of these creatures that swam Devonian seas.The Paleozoic Era lasted 291 million years from the start of the Cambrian Period 542 million years ago until the end of the Permian Period 251 million years ago. Life of every kind went through ...Study the diagram of the geologic time scale. A time scale measured in Millions of years ago or M Y A. Cenozoic Era includes Quaternary Period, 0 to 1.6 M Y A, and Tertiary Period, 1.6 to 66.4 M Y A. Mesozoic Era includes Cretaceous Period, 66.4 to 144 M Y A, Jurassic Period, 144 to 208 M Y A, Triassic Period, 208 to 245 M Y A. …The first started when the climate was cooling in 443 Ma, and the second wave began when the climate began to warm again 1 million years later, and even more species were wiped out. As life began to recover in the Silurian Period (444-419 Ma), fish with jaws evolved and the first small insect-like animals moved onto land.Oct 10, 2023 · The Paleozoic Era, which began more than 540 million years ago and lasted more than 160 million years, was an important time period for the evolution of life on Earth. During this era, the first fish and land plants appeared, along with the first amphibians, reptiles, and eventually reptiles that could fly. However, the event that marked the end of the Paleozoic period was the massive extinction that wiped out nearly 96% of all marine life and 70% of land animals. Only a few species survived including some reptiles. In what era did the extinction of dinosaurs happened? ... The first is called the Paleozoic Era. Plants, insects, fish, …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 first started when the climate was cooling in 443 Ma, and the second wave began when the climate began to warm again 1 million years later, and even more species were wiped out. As life began to recover in the Silurian Period (444-419 Ma), fish with jaws evolved and the first small insect-like animals moved onto land.Fish evolved, and plants and animals started the move from the ocean onto dry land. Most plants and animals from this time are extinct in our modern world, which is why the Paleozoic is named for “ancient life." The 6 periods in this era are described below, as shown in the "Fossils Tell a Scientific Story" exhibit in the Hall of Evolution.Paleozoic (541-252 million years ago) means ‘ancient life.’ The oldest animals on Earth appeared just before the start of this era in the Ediacaran Period, but scientists had not yet discovered them when the geologic …The first period of the Cenozoic Era is called the Tertiary Period, which began around 65 million years and ended around 2.6 million years ago. ... During the late Paleozoic Era, all of Earth's ...The first period of the Cenozoic Era is called the Tertiary Period, which began around 65 million years and ended around 2.6 million years ago. ... During the late Paleozoic Era, all of Earth's ...This led to the widespread distribution of tetrapods during the early Carboniferous period. The Paleozoic Era and the Evolution of Vertebrates. The climate and geography of Earth was vastly different during the Paleozoic Era, when vertebrates arose, as compared to today. The Paleozoic spanned from approximately 542 to 251 million years ago.Paleozoic Era (541 to 252 million years ago): Fossils from this time period include trilobites, brachiopods, early fish and amphibians, and coral reefs. Mesozoic Era (252 to 66 million years ago): Fossils from this time period include dinosaurs, ammonites, and early birds and mammals.

Jul 7, 2022 · The Paleozoic Era (542–251 mya) Advertisement. The Cambrian Period saw the explosion of new kinds of invertebrate animals in the oceans, including trilobites (Figure 2), primitive kinds of shellfish, including brachiopods and molluscs, and other groups of invertebrates that failed to survive the end of this period. . Humboldt craigslist cars and trucks

what is the first period of the paleozoic era

The Geological time succeeding Azoic Era, was dramatic and rich in life. This period is divided into three eras. These were significant periods in earth's history. Of these, the oldest era was the Paleozoic era. It ranged from 600 to 210 million years ago. Thus its duration was nearly 390 million years.The Paleozoic began with the Cambrian Period, 53 million years best known for ushering in an explosion of life on Earth. This "Cambrian explosion" included the evolution of arthropods...This first major flowering of multicellular eukaryotes (organisms with neucleated cells), which is known as the Cambrian explosion, marks the onset of the Cambrian period—the first period of the first era (the Paleozoic) of the Phanerozoic eon (Mayr 2001). The Phanerozoic eon is divided into three eras: The Paleozoic, Mesozoic, and Cenozoic ...The first period of the Cenozoic Era is called the Tertiary Period, which began around 65 million years and ended around 2.6 million years ago. ... During the late Paleozoic Era, all of Earth's ...Paleozoic Era, or Palaeozoic Era, Major interval of geologic time, c. 542–251 million years ago. From the Greek for “ancient life,” it is the first era of the Phanerozoic Eon and is followed by the Mesozoic Era. It is divided into six periods: (from oldest to youngest) the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and ...Jan 23, 2017 · The period, and the Paleozoic era, came to a calamitous close 251 million years ago, marking a biological dividing line that few animals crossed. ... Earth’s first “super predator” was ... 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.The first known major mass extinction event occurred during the Ordovician Period of the Paleozoic Era on the Geologic Time Scale. At this time in the history of Earth, life was in its early stages. The first known life forms appeared about 3.6 billion years ago, but by the Ordovician Period, larger aquatic life forms had come into existence.Flight was first achieved also during the Carboniferous Period as insects evolved wings. The Permian extinction, at the end of the Paleozoic Era, eliminated such major invertebrate groups as the blastoids (an extinct group of echinoderms related to the modern starfish and sea lilies), fusulinids, and trilobites.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 is the earliest and longest of three geologic eras of the Phanerozoic Eon. It lasted from 541 to 251.902 million years ago and is subdivided into six geologic periods from oldest to youngest: Cambrian (541 million to 485.4 million years ago), Ordovician (485.4 million to 443.8 million years ago), Silurian (443.8 million to 419 ....

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