What is the Paleozoic era?

We explain to you what the Peleozoic era is and what this historical period consisted of. In addition, the stages that constitute it and its animals.

1. What is the Paleozoic era?

It is known as Paleozoic era, was Primary or simply Paleozoic, at a period of the geological time scale , that is, the scale with which the history of the world is measured , inscribed next to the Mesozoic and Cenozoic in the Phanerozoic Eon (542 years ago million years to the present).

The term Paleozoic means “ancient life” (from the Greek  palaio , “old”, and  zoe , “life”), a name that was assigned to this period because it is where the oldest known life forms proliferate: beings with shells or exoskeletons. 

The beginning of this temporary stage, which lasted more than 290 million years ago , is located 542 million years ago with the dissolution of the Pannotia supercontinent and culminates 251 million years ago, with the beginning of the Mesozoic and the formation of the Pangea supercontinent  .

The Paleozoic era  was an extremely rich period from a biological point of view , transition between the kingdom of invertebrate animals and that of vertebrates or higher. During this period the seas literally filled with life and migrated to the earth, conquering new habitats and expanding throughout the planet.

Climatically, this period was characterized by the increase in the warmth of the planet , which led to an average stability that coincides with the proliferation of oxygen in the atmosphere . This happened after the glaciation of the upper Ordovician, a cold wave that caused one of the two great mass extinctions of the Phanerozoic Aeon.

2. Paleozoic era stages

The Cambrian period is characterized by its large amount of marine life.

The Paleozoic era is classified into a set of six periods, which are:

• Cambrian or Cambrian (makes 541  m .  –  made 485  m .) . This period is characterized by the “great explosion” of life, which crammed the seas and gave way, for the first time in the history of the planet, to multicellular living beings, much more complex than protists and bacteria . Fifty edges of living beings have their origin in this period, beginning biomineralization (appearance of shells and shells).
• Ordovician (makes 485  m .a .  – makes 444  m .) . Life was contained in the seas, since the absence of abundant atmospheric oxygen made life on earth impossible. However, the diversification of living beings in the sea was exponential, and towards the end of the period the first plants and fungi were out of the water. There was also a glaciation in almost all regions of the globe, causing a mass extinction of the Ordovician-Silurian, only surpassed by the subsequent extinction of the Permian-Triassic.
• Silúrico (444  m ago – 416 ma ago  ) . After extinction, life on earth continues to be vegetal and restricted to marshy environments, but in the sea there is a repopulation of complex animals such as cartilaginous fish and spiny sharks, which dominated the hot and abundant waters along the equator. At the end of the Silúrico another mass extinction event occurred, although much smaller than the previous one, known as the Lau event, due to the decrease in sea water levels.
• Devonian (416  ma ago – 359 ma ago  ) . In this period, bony fish and large coral reefs appear, trilobites and ammonites predominate, already extinct, but popular, Paleozoic life forms. Seedlings spread across the ground and finally appear the first amphibians, as well as the first terrestrial arthropods. Towards the end of the period another important extinction occurred, which mainly affected marine life.
• Carboniferous (359  m .a -. Makes 299  m .) . Its name comes from the fact of the formation of the majority of the mineral coal extracted in our time, product of the burial of huge contingents of forests and plant life. Amphibians invade the earth and give rise to the first reptiles. The insects were abundant and of enormous size, given the abundance of environmental oxygen, which reached levels of 35% of the atmosphere . This period was very active volcanically and witnessed the emergence of Pangea, culminating in a new glaciation.
• Permian (299  ma ago – 251 ma ago  ) . The last stage of the Paleozoic era, witnessed the appearance of the first mammals, turtles and primitive dinosaurs (lepidosaurs and arcosaurs). Climatically the period tended towards drought and aridity, receding glaciers and drying out many swamps. Towards the end of the period there was a mass extinction of the Permian-Triassic, one of the largest of those recorded, in which 90% of marine life and 70% of terrestrial life ended. It is not very well known why this catastrophic event was caused from a biological point of view.