The Cambrian Period
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The Cambrian Period
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Author : Charles River
language : en
Publisher:
Release Date : 2020-10-16
The Cambrian Period written by Charles River and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-10-16 with categories.
*Includes pictures *Includes a bibliography for further reading The early history of Earth covers such vast stretches of time that years, centuries, and even millennia become virtually meaningless. Instead, paleontologists and scientists who study geochronology divide time into periods and eras. The current view of science is that Earth is around 4.6 billion years old, and the first 4 billion years of its development are known as the Precambrian period. For the first billion years or so, there was no life in Earth. Then the first single-celled life-forms, early bacteria and algae, began to emerge. It's unclear where they came from or even if they originated on this planet at all, but this gradual development continued until around four billion years ago when suddenly (in geological terms) more complex forms of life began to emerge. Scientists call this time of an explosion of new forms of life the Paleozoic Era, and it stretched from around 541-250 million years ago (Mya). In the oceans and then on land, new creatures and plants began to appear in bewildering variety, and by the end of this period, life on Earth had diversified into a myriad of complex forms that filled virtually every habitat and niche available in the seas and on the planet's only continent, Pangea. Despite all of the scientific advances made in the past few centuries, including an enhanced understanding of Earth's geological past, very little is known about the planet's early history. It is generally accepted that the planet formed somewhere in the region of 4.5 billion years ago, and at some point, the first life appeared in the form of tiny, single-celled creatures, but scientists are unsure of what this life looked like. One of the problems for those seeking to trace the history of life on Earth is that modern scholars are almost entirely dependent on fossil records, but the earliest types of life left few fossils. The best fossils are formed from the bones and hard body parts of dead creatures, but the earliest types of life were so small that they had no bones or cartilage and thus left no fossils. Thus, even though the Precambrian Period (4,600-541 millions of years ago (Mya)) covers over 80% of the entire history of the planet, scientists have very little idea of what forms of life existed then. Then, as Earth entered the Cambrian Period, there was a relatively sudden increase in life form diversity throughout the oceans. Completely new forms of life, more complex and more diverse than anything that had been seen before, began to spread. This acceleration in the evolution of new forms of life was so dramatic that this has come to be known as the "Cambrian explosion." Although new species in the Cambrian explosion developed almost entirely in the oceans, the land was not entirely devoid of life. Though there were no plants or animals, mats of cyanobacteria and other types of microbes covered large terrestrial areas. Scientists have discovered the tracks of a creature that were left in mud that existed 551 Mya, and those tracks were left by leg-like appendages. Was this a fish-like creature that temporarily invaded the land, or was it something completely different than anything that exists today? There is no general consensus, but the Cambrian Period left a rich fossil record that provides a clear idea of the development of life during this time. At the same time, new discoveries are continually being made, and the more scientists discover about this mysterious period, the more their understanding of ancient Earth changes. The Cambrian Period: The History and Legacy of the Start of Complex Life on Earth looks at the development of the era, the extinction event that preceded it, and how life began to evolve during it. Along with pictures depicting important people, places, and events, you will learn about the Cambrian Period like never before.
The Cambrian Period
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Author : Charles River Editors
language : en
Publisher:
Release Date : 2020
The Cambrian Period written by Charles River Editors and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020 with categories.
Early Life
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Author : Thom Holmes
language : en
Publisher: Infobase Publishing
Release Date : 2008
Early Life written by Thom Holmes and has been published by Infobase Publishing this book supported file pdf, txt, epub, kindle and other format this book has been release on 2008 with Earth sciences categories.
Discusses the Cambrian era in Earth's history, when the first forms of life appeared and began to flourish and evolve.
The North American Continent During Cambrian Time
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Author : Charles Doolittle Walcott
language : en
Publisher:
Release Date : 1892
The North American Continent During Cambrian Time written by Charles Doolittle Walcott and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1892 with Geology categories.
The Cambrian Period
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Author : Charles River
language : en
Publisher:
Release Date : 2020-10-16
The Cambrian Period written by Charles River and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-10-16 with categories.
*Includes pictures *Includes a bibliography for further reading The early history of Earth covers such vast stretches of time that years, centuries, and even millennia become virtually meaningless. Instead, paleontologists and scientists who study geochronology divide time into periods and eras. The current view of science is that Earth is around 4.6 billion years old, and the first 4 billion years of its development are known as the Precambrian period. For the first billion years or so, there was no life in Earth. Then the first single-celled life-forms, early bacteria and algae, began to emerge. It's unclear where they came from or even if they originated on this planet at all, but this gradual development continued until around four billion years ago when suddenly (in geological terms) more complex forms of life began to emerge. Scientists call this time of an explosion of new forms of life the Paleozoic Era, and it stretched from around 541-250 million years ago (Mya). In the oceans and then on land, new creatures and plants began to appear in bewildering variety, and by the end of this period, life on Earth had diversified into a myriad of complex forms that filled virtually every habitat and niche available in the seas and on the planet's only continent, Pangea. Despite all of the scientific advances made in the past few centuries, including an enhanced understanding of Earth's geological past, very little is known about the planet's early history. It is generally accepted that the planet formed somewhere in the region of 4.5 billion years ago, and at some point, the first life appeared in the form of tiny, single-celled creatures, but scientists are unsure of what this life looked like. One of the problems for those seeking to trace the history of life on Earth is that modern scholars are almost entirely dependent on fossil records, but the earliest types of life left few fossils. The best fossils are formed from the bones and hard body parts of dead creatures, but the earliest types of life were so small that they had no bones or cartilage and thus left no fossils. Thus, even though the Precambrian Period (4,600-541 millions of years ago (Mya)) covers over 80% of the entire history of the planet, scientists have very little idea of what forms of life existed then. Then, as Earth entered the Cambrian Period, there was a relatively sudden increase in life form diversity throughout the oceans. Completely new forms of life, more complex and more diverse than anything that had been seen before, began to spread. This acceleration in the evolution of new forms of life was so dramatic that this has come to be known as the "Cambrian explosion." Although new species in the Cambrian explosion developed almost entirely in the oceans, the land was not entirely devoid of life. Though there were no plants or animals, mats of cyanobacteria and other types of microbes covered large terrestrial areas. Scientists have discovered the tracks of a creature that were left in mud that existed 551 Mya, and those tracks were left by leg-like appendages. Was this a fish-like creature that temporarily invaded the land, or was it something completely different than anything that exists today? There is no general consensus, but the Cambrian Period left a rich fossil record that provides a clear idea of the development of life during this time. At the same time, new discoveries are continually being made, and the more scientists discover about this mysterious period, the more their understanding of ancient Earth changes. The Cambrian Period: The History and Legacy of the Start of Complex Life on Earth looks at the development of the era, the extinction event that preceded it, and how life began to evolve during it. Along with pictures depicting important people, places, and events, you will learn about the Cambrian Period like never before.
Cambrian Explosion
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Author : D Erwin
language : en
Publisher: Bedford
Release Date : 2013-01-18
Cambrian Explosion written by D Erwin and has been published by Bedford this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013-01-18 with Education categories.
The Cambrian Period records one of the most extraordinary transitions in the history of life. Although animals may have first appeared nearly 700 million years ago, with the earliest sponges, their initial diversifications appear to have been modest until a richly diverse fossil fauna appeared abruptly about 170 million years later. In The Cambrian Explosion, Erwin and Valentine synthesize research from many fields to explain why there was such remarkable novelty of animal forms.
The Emergence Of Animals
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Author : Mark A. McMenamin
language : en
Publisher: Columbia University Press
Release Date : 1990
The Emergence Of Animals written by Mark A. McMenamin and has been published by Columbia University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 1990 with Computers categories.
The authors explore the late Precambrian and earliest Cambrian fossil record to explain the Cambrian phenomenon and discuss the possibility of a major turnover in marine ecology at the beginning of the Cambrian period or whether a new, improved type of animal appeared at this time. They support their often controversial conclusions with photos and illustrations of fossils, some never before published.
Cambrian Ocean World
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Author : John Foster
language : en
Publisher: Indiana University Press
Release Date : 2014-06-06
Cambrian Ocean World written by John Foster and has been published by Indiana University Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2014-06-06 with Science categories.
This volume, aimed at the general reader, presents life and times of the amazing animals that inhabited Earth more than 500 million years ago. The Cambrian Period was a critical time in Earth's history. During this immense span of time nearly every modern group of animals appeared. Although life had been around for more than 2 million millennia, Cambrian rocks preserve the record of the first appearance of complex animals with eyes, protective skeletons, antennae, and complex ecologies. Grazing, predation, and multi-tiered ecosystems with animals living in, on, or above the sea floor became common. The cascade of interaction led to an ever-increasing diversification of animal body types. By the end of the period, the ancestors of sponges, corals, jellyfish, worms, mollusks, brachiopods, arthropods, echinoderms, and vertebrates were all in place. The evidence of this Cambrian "explosion" is preserved in rocks all over the world, including North America, where the seemingly strange animals of the period are preserved in exquisite detail in deposits such as the Burgess Shale in British Columbia. Cambrian Ocean World tells the story of what is, for us, the most important period in our planet's long history.
The Cambrian Fossils Of Chengjiang China
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Author : Hou Xian-Guang
language : en
Publisher: John Wiley & Sons
Release Date : 2017-03-08
The Cambrian Fossils Of Chengjiang China written by Hou Xian-Guang and has been published by John Wiley & Sons this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-03-08 with Science categories.
The celebrated lower Cambrian Chengjiang biota of Yunnan Province, China, represents one of the most significant ever paleontological discoveries. Deposits of ancient mudstone, about 520 million years old, have yielded a spectacular variety of exquisitely preserved fossils that record the early diversification of animal life. Since the discovery of the first specimens in 1984, many thousands of fossils have been collected, exceptionally preserving not just the shells and carapaces of the animals, but also their soft tissues in fine detail. This special preservation has produced fossils of rare beauty; they are also of outstanding scientific importance as sources of evidence about the origins of animal groups that have sustained global biodiversity to the present day. Much of the scientific documentation of the Chengjiang biota is in Chinese, and the first edition of this book was the first in English to provide fossil enthusiasts with a comprehensive overview of the fauna. The second edition has been fully updated and includes a new chapter on other exceptionally preserved fossils of Cambrian age, exciting new fossil finds from Chengjiang, and a phylogenetic framework for the biota. Displaying some 250 figures of marvelous specimens, this book presents to professional and amateur paleontologists, and all those fascinated by evolutionary biology, the aesthetic and scientific quality of the Chengjiang fossils.
Epigenetic Mechanisms Of The Cambrian Explosion
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Author : Nelson R Cabej
language : en
Publisher: Academic Press
Release Date : 2019-10-12
Epigenetic Mechanisms Of The Cambrian Explosion written by Nelson R Cabej and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2019-10-12 with Science categories.
Epigenetic Mechanisms of the Cambrian Explosion provides readers with a basic biological knowledge and epigenetic explanation of the biological puzzle of the Cambrian explosion, the unprecedented rapid diversification of animals that began 542 million years ago. During an evolutionarily instant of ~10 million years, which represents only 0.3% of the time of existence of life on Earth, or less than 2% of the time of existence of metazoans, all of the 30 extant body plans, major animal groups (phyla) and several extinct groups appeared. The work helps address this phenomena and tries to answer remaining questions for evolutionary biology, epigenetics, and scientific researchers. The book recognizes and presents objective representations of alternative theories for epigenetic evolution in this period, with the author drawing on his epigenetic theory of evolution to explain the causal basis of the Cambrian explosion. Both empirical evidence and theoretical arguments are presented in support of this thought-provoking epigenetic theory. Explains the Cambrian explosion from an entirely epigenetic view Takes a causal rather than descriptive approach to the phenomenon Allows for a broad readership, including those with only a basic biological knowledge, while maintaining scientific rigor