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As there are eras


What are the eras</a>

The whole history of the life of the Earth is divided into long stretches, which are commonly called eras.

Each is distinguished by certain changes in geography and climate, as well as by significant developments in the flora and fauna.

Archean era

This era begins with the formationEarth, as a planet, and lasts about 1 billion years. It was during this period that the first inhabitants of our planet appeared - anaerobic bacteria. Then there was photosynthesis - the most important stage in the evolution of life, which caused the division of the organic world into vegetable and animal life. At the end of this period, multicellularity and the sexual process appeared, which increased the possibility of adaptation to environmental conditions.

The first photosynthetic organisms were blue-green algae and pre-nuclear cyanobacteria.

The Proterozoic Era

A huge period of developmentThe earth, which lasted about 2 billion years. During it, the first protozoan organisms appeared on our planet. During this period, bacteria and algae reach their dawn, the largest deposits of iron ores of organic origin are formed.

Living organisms become multicellular(Archeocyats, sponges), they form organs. They change the shape and composition of the earth's crust, form the biosphere and contribute to the accumulation of oxygen in the atmosphere. At the end of the Proterozoic era, ringworms appear. All life processes of this period occur in the ocean.


This segment is presented in 6 periods: Cambridge, Ordovician, Silurian, Devonian, Carboniferous and Permian. In the animal world, various species of fish appear, including shark, appear, and then corals are dying out. A little later comes the age of amphibians - grasshoppers, beetles, reptiles. The plant world of this era is represented by the development of dense forests along the banks of rivers, consisting of treelike ferns and the first coniferous trees.

The geography and climate of this period is constantlyAre changing. Glaciation at the end of the Ordovician period is followed by warming and mild climate. In the Devonian period, torrential rains alternate with drought, in the Carboniferous there comes the glaciation, which then gives way to warming, heat and dry climate. Such a variety of climatic conditions is due to the continual change in the position of the continents and the greatest cataclysms.

As a result, various mountain peaks appear, including the Ural mountain range and the Himalayas.

Mesozoic Era

The Mesozoic era is represented by the Triassic, Jurassic andChalky periods. In the animal world, dinosaurs and various reptiles become the dominant group, there are frogs, sea and land turtles, new types of shrimp and coral. A little later, predecessors of modern insects and birds appear. At the end of the era, dinosaurs and pterosaurs die.

The climate is becoming softer and the whole landIt grows in various vegetation: predecessors of modern pines and cypresses, the first flowering plants. The relationship between plants and insects is being established. In the Mesozoic era, the continents split and are removed from each other, islands are formed. The Atlantic Ocean is being formed and expanding, the sea is flooding huge areas of land.

The Cenozoic Era

The modern era, which began 66 million. years ago. In this period there are angiosperms, birds, mammals and humans. In the middle of the era, there already exist main groups of representatives of the kingdoms of living nature. Develop bushes and grass, there are meadows and steppes. The main types of biogeocenosis in nature and agrocenosis are formed. There is the use of nature by man to meet his needs. As a result of human influence, the organic world and nature change.

As there are eras Was last modified: June 21st, 2017 By Jyebaitj
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