Paleozoic Era: what it was, periods, end, summary

A Paleozoic Era it was a geological era which extended from 542 to 251 million years, being the first subdivision of the Phanerozoic Eon. It is subdivided into six periods, which begin with the Cambrian, marked by a great biological diversification of life forms on planet Earth, initially in the oceans, such as trilobites. Over time, and as the planet's climate changed, new species and new forms of life emerged, some of which began to occupy the surface. Forests and animals such as reptiles, insects, small mammals and jawed fish emerged in this geological era.

The end of the Paleozoic Era, 251 million years ago, in the Permian Period, was marked by one of the largest mass extinctions ever. recorded on planet Earth, and which claimed the lives of most species of animals and plants, both terrestrial and marine.

Read too: Mesozoic Era — details about the geological era that followed the Paleozoic Era

Topics in this article

• 1 - Summary of the Paleozoic Era
• 2 - What was the Paleozoic Era?
• 3 - Background of the Paleozoic Era
• 4 - Characteristics of the Paleozoic Era
• 5 - Periods of the Paleozoic Era
  • → Cambrian (542 to 488 million years)
  • → Ordovician (488 to 444 million years old)
  • → Silurian (444 to 416 million years)
  • → Devonian (416 to 359 million years)
  • → Carboniferous (359 to 299 million years)
  • → Permian (299 to 251 million years)
• 6 - End of the Paleozoic Era
• 7 - Geological time scale
• 8 - Exercises on the Paleozoic Era

Summary about the Paleozoic Era

• The Paleozoic Era was the geological era that ushered in the Phanerozoic Eon. It extended from 542 million years ago to 251 million years ago.

• It is divided into six periods:

  • Cambrian;

  • Ordovician;

  • Silurian;

  • Devonian;

  • Carboniferous;

  • Permian.

• It was preceded by the Precambrian, which extended from the day the Earth originated until 542 million years ago, when the Paleozoic Era began.

• The era that preceded the Paleozoic is called Neoproterozoic, and was marked by the fragmentation of Rondínia (supercontinent), severe glaciations and the emergence of multicellular organisms.

• The Paleozoic Era was characterized by the emergence and spread of diverse forms of animal and plant life, initially aquatic and, later, terrestrial.

• The Earth's climate underwent severe transformations in the Paleozoic Era, with the occurrence of glaciations, which dropped temperatures, followed by hot and humid weather.

• Forest formations emerged during the Paleozoic Era, as did many species of fish, reptiles, insects and amphibians.

• This geological era ended with a great mass extinction, during the Permian Period, which caused the disappearance of most of the planet's living species.

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What was the Paleozoic Era?

The Paleozoic Era it was the first geological era of the Phanerozoic Eon (542 million years - present). Stretched from 542 to 251 million years ago. This era marked the end of the Proterozoic Eon and inaugurated the current phase of development and evolution of planet Earth and Earth. diversification of existing life forms, with the emergence of large species, mainly reptiles and amphibians.

The term Paleozoic originates from Greek and means “ancestral life”. The name of this period, therefore, refers to the new forms of macroscopic life that originated in this period of time, many of which gave rise to current species.

The Paleozoic Era is divided into six different periods:

• Cambrian (542-488 million years);

• Ordovician (488-444 million years old);

• Silurian (444-416 million years ago);

• Devonian (416-359 million years);

• Carboniferous (359-299 million years);

• Permian (299-251 million years).

Background to the Paleozoic Era

Fossil records of the Edicara fauna, which appeared in the Pre-Cambrian.

The Paleozoic Era was preceded by the Neoproterozoic Era, which corresponded to the last geological era of the Proterozoic Eon, which extended from 2500 to 542 million years in the geological past. Since it preceded the Cambrian Period, which ushered in the Phanerozoic, the entire period of time that precedesu the Paleozoic Era (4.5 billion to 542 million years) receivesu the name of Precambrian.

During the Neoproterozoic Era, there was another supercontinent, formed long before from Pangea. This supercontinent was named Rondínia, and was formed around 1.6 billion years ago. Its fragmentation began with the Neoproterozoic Era, at the same time, several glaciations (fall in terrestrial temperatures and increase in ice cover), some very severe, occurred. In addition to the sudden changes in the climate, what is called modern tectonics began, characterized by transformations in the ocean floor.^|1|

The first metazoan animals appeared during the Neoproterozoic Era, which represents an important evolution of life on planet Earth. Previously composed essentially of unicellular species, the terrestrial biota beganor to diversify and also be formed by multicellular animals.

Still on the biological evolution of the Earth in the Precambrian, it is essential to mention the Edicara fauna, such as A group of living beings similar in appearance to leaves that lived at the bottom of the oceans became known. Most of them had a flat, discoid shape, which raised many doubts among researchers about whether they belonged to the animal kingdom or the plant kingdom. Fossil records of these living beings were found near Australia, in the Edicara Hills, which is why they get their name.^|2|

See too: What is the origin of life?

Characteristics of the Paleozoic Era

The Paleozoic Era began the Phanerozoic Eon, and extended between 542 million years and 251 million years into the geological past. Therefore, teve duration of 291 million years.

This geological era was very important with regard to the geological and biological evolution of planet Earth, since it was characterized by the formation, first, of a supercontinent (Gondwana) and other smaller parcels of emerged land, and, later, by the consolidation of Pangea.

In second place, It was during the Paleozoic Era that the so-called It isxexplosion wambrian. It is the rapid emergence, thinking on the geological time scale, of a large number of new species of animals and plants, many of which are no longer just aquatic and have become terrestrial. Therefore, the Paleozoic Era was characterized by the biological diversification of planet Earth, which gained prominence with the emergence of the first vertebrate animals and also with the spread of these living beings across the emerging lands (continents).

The Paleozoic Era was very important for the biological evolution of planet Earth.

Planet Earth's climate underwent many changes during the Paleozoic Era. As in the previous geological era, there were periods of glaciation, in which average temperatures plummeted, giving rise to broad ice covers. However, ice ages alternated with warm and humid periods, with frozen areas being restricted to the Earth's poles. With the formation of Pangea, however, the situation changed once again, and the supercontinent's climate became hotter and drier in certain areas.

Periods of the Paleozoic Era

The Paleozoic Era was divided into six geological periods, which we will briefly discuss below.

→ Cambrian (542 to 488 million years)

Illustration of a trilobite, an animal that lived during the Paleozoic Era.^[1]

The Cambrian period was the first of the Cenozoic Era. It was marked by a practically uniform climate across planet Earth, with a hot and humid appearance in most regions. The Earth's surface was made up of a supercontinent, called Gondwana, and other continents smaller portions that constituted small portions of emerging lands, very different from the current configuration of the planet Earth.

During the Cambrian, the call andxexplosion wambrian, the rapid expansion, in terms of geological time, of existing animal and plant species. It was during this period that invertebrate animal species capable of producing exoskeletons and shells emerged, such as trilobites. It is noted that these animals were essentially aquatic. Find out more details about this period of the Paleozoic Era by clicking here.

→ Ordovician (488 to 444 million years old)

The Ordovician Period followed the Cambrian, and the planet's climate continuesgo hot and humid most of the time. The exception occurred at the end of the Ordovician, when the continuity of tectonic movements caused a huge block of Gondwana moved close to the southern pole, starting a glaciation or ice age. ice. This sudden drop in temperatures caused the extinction of some existing species.

The animals of this period continued to be, predominantly, aquatic invertebrates, which now existed in greater numbers, as well as seaweed. However, the appearance of the first coral reefs, fish and land plants, such as mosses, was identified. The living beings that arisewill in the Ordovician no had complex organisms.

→ Silurian (444 to 416 million years)

In the Silurian Period, planet Earth's climate changesor, and yousee end of the ice age started in the Ordovician. With the continued movement of the continents, the general characteristics of the atmosphere approached what we have today, with cold at the poles and a hot and humid climate close to the Earth's Equator. The melting of ice from the last glaciation, however, caused a rise in sea level.

Coral reefs continued to grow, at the same time that the animal kingdom gained new species of fish with jaws, in addition to the first land animals, which began to occupy lowered terrain.

→ Devonian (416 to 359 million years)

Fossil land plant that existed during the Devonian.^[2]

The Devonian Periodhe was characterized by hot and dry climate in many locations in the interior of the continents, who continued to move and were heading towards each other. Many marine animals emerged and developed during the Devonian, such as sharks, at the same time that species such as trilobites began to disappear.

Some representatives of amphibians appeared during the Devonian, including those typically terrestrial. Note also the broad development of continental vegetation and the formation of the first forests.

→ Carboniferous (359 to 299 million years old)

The movement of the continents on a collision course continued, at the same time that the climate of planet Earth, during most of the Carboniferous period, was tropical. However, at the end of this period, general temperatures plummeted, and a new ice age began, called the Carboniferous-Permian glaciation, as it extended into the subsequent period.

Climate change has caused the lowering of ocean levels and, consequently, the disappearance of some marine species. On land, the first reptiles appeared that laid eggs with shells, an important evolutionary trait of these animals. Winged insects, many of them giants, appeared during the Carboniferous, and forests continued to grow. Along with them came charcoal deposits, especially in the Northern Hemisphere.

→ Permian (299 to 251 million years)

Pangea formed during the Permian.

The Permian was the last period of the Paleozoic Era. In that time span of 48 million years, Pangea formed, and shallow seas became increasingly rare. Due to the formation of a large and unique continental mass, Planet Earth's climate has undergone a sudden change, characterized by cold areas at the poles and hot areas near the ANDframe. Large deserts and areas of hot, dry climates formed in the interior of Pangea.

The number and diversity of reptiles on planet Earth increased at the same time that they began to spread over the surface. Cynodonts, as the ancestors of mammals were known, also appeared in the Permian. During this period, seed plants began to form a denser population, close to the forests, which gained new locations, especially close to the Equator, where there was a favorable climate for their development.

Also access: Cenozoic Era — details about the geological era we find ourselves in today

End of the Paleozoic Era

The Paleozoic Era ended 251 million years ago, giving way to the PCarboniferous period of the Mesozoic Era. The end of the Permian, the last period of the Paleozoic Era, was marked by the greatest mass extinction experienced in the world. planet Earth, when 96% of all species of marine animals and plants and 70% of terrestrial species disappeared.

Geological time scale

The timeline used to record the development and evolution of planet Earth is called the geological time scale. This time scale has as its starting point the emergence of the Earth, 4.6 billion years ago, and extends to the present day. Geological time, for better understanding and analysis, is divided as follows:

• Aeons: longer time intervals, measured in billions or millions of years.

• Geological eras: Measured in millions of years, they are the subdivisions of geological eons.

• Periods: measured in millions of years, or thousands, in the most recent period, and represent the subdivision of geological eras.

• Seasons: shorter time intervals on the geological scale, and represent the subdivision of periods.

Exercises on the Paleozoic Era

Question 1

The Paleozoic Era was the one that began the Phanerozoic Eon, and represented the beginning of the Earth's modern transformations. Because of this, it is said that the Paleozoic Era was very important for the evolutionary history of our planet. Read the following alternatives carefully and select the one that correctly describes an event from the Paleozoic Era:

A) intense magmatic activity and constant meteorite impacts.

B) first global glaciation, followed by mass extinction.

C) emergence of terrestrial animals and diversification of animal and plant species.

D) appearance of large reptiles and dinosaurs.

E) fragmentation of Laurasia and Gondwana, forming the current continents.

Resolution:

Alternative C

Life on planet Earth stopped being predominantly marine (or aquatic) and also became terrestrial during the Paleozoic Era. The other alternatives refer to the Hadean Eon (A), the Proterozoic Era (B), the Mesozoic Era (D) and the transition between the Mesozoic Era and the Cenozoic Era (E).

Question 2

(UEMG) we know that over billions of years, the Earth has undergone different transformations ranging from the cooling and solidification of layers to the results of anthropogenic transformations.

In this context, mark V for true statements and F for false statements.

( ) The Pre-Cambrian Era was characterized by the lack of life on the planet and the formation of the first magmatic rocks.

( ) The Paleozoic Era was characterized by the formation of large mountain ranges, such as the Andes and the Alps.

( ) The Mesozoic Era was marked by the fragmentation of the Gondwana continent, which resulted in the formation of the African and South American continents and the Atlantic Ocean.

( ) The Cenozoic Era was marked by the great burial of forests in different parts of the globe, which resulted in the formation of mineral coal deposits.

Select the alternative that presents the CORRECT sequence:

A) F V F V.

B) V F V F.

C) V V F V.

D) V F F F.

Resolution:

Alternative B

The second statement is false because, during the Paleozoic, there was no formation of the aforementioned mountain ranges, which began to be built only in the Cenozoic. The last statement is also incorrect, as the first coal deposits began to form in the Paleozoic. The rest are correct.

Grades

^|1|TEIXEIRA, Wilson.; FAIRCHILD, Thomas Rich.; TOLEDO, Maria Cristina Motta de; TAIOLI, Fabio. (Eds.) Deciphering the Earth. São Paulo, SP: Companhia Editora Nacional, 2009, 2nd ed.

^|2|SILVA, Marcos. The enigmatic Fauna of Ediacara. In: Biological Sheet. UFV: 2017, vol. 8. Available in: https://folhabiologica.crp.ufv.br/?p=834.

Image credits

^[1]Віщун / Wikimedia Commons (reproduction)

^[2]James St. John/Wikimedia Commons (reproduction)

Sources

SANTOS, Teresa. Mass extinction: the five biggest in history. Invivo – Fiocruz, 23 September. 2022. Available in: https://www.invivo.fiocruz.br/cienciaetecnologia/extincao-em-massa-5-maiores/.

TEIXEIRA, Wilson.; FAIRCHILD, Thomas Rich.; TOLEDO, Maria Cristina Motta de; TAIOLI, Fabio. (Eds.) Deciphering the Earth. São Paulo, SP: Companhia Editora Nacional, 2009, 2nd ed.

YOUTH AND EDUCATION IN SCIENCE (YES). Paleozoic. United States Geological Survey (USGS), [n.d.]. Available in: https://www.usgs.gov/youth-and-education-in-science/paleozoic.

Would you like to reference this text in a school or academic work? Look:

GUITARRARA, Paloma. "Paleozoic Era"; Brazil School. Available in: https://brasilescola.uol.com.br/geografia/era-paleozoica.htm. Accessed on November 10, 2023.