Era is a large time period, a historical period. This is the name of the system of reckoning, as well as the beginning of this reckoning. The entire history of our planet can be conditionally divided into long periods. Among themselves, they differ in certain climatic and geographical changes, as well as a significant breakthrough in the development of the animal and plant world. Many are interested in what eras are and what they represent. Consider the main stages of the development of the Earth.
Archaean era
At this time, our planet was formed, the period lasted about a billion years. There was no life on Earth yet, chemical reactions took place in the ocean between acids, alkalis, s alts. The Archean era gave rise to protein matter. It was then that living organisms began to emerge.
Proterozoic era
The longest period of the planet's development, which lasted about 2 billion years. At this time, algae and bacteria develop, organisms acquire their own organs, they become multicellular. An era is a time period when something new appears, the Proterozoic stage was distinguished by the formation of iron ore deposits. This period is characterized by the fact that all life processes take place in the ocean.
Paleozoic era
This is a period characterized by a constant change in climatic conditions, it is divided into 6 stages. At this time, the flora and fauna develop, many species of fish appear. Coniferous trees and ferns grow along the banks. Around the middle of the era, the first amphibians appeared in the form of reptiles, beetles, and grasshoppers. The period is characterized by constant cataclysms, changes in the shape of the continents.
Mesozoic era
A stage consisting of the Triassic, Jurassic and Cretaceous periods. The Mesozoic era is the appearance of land and sea turtles, frogs, shrimps, new varieties of corals. The dominant position is occupied by reptiles and dinosaurs. In the middle of the era, the first representatives of modern birds and insects appear. During the Cretaceous period, pterosaurs and dinosaurs became extinct.
At this time, climatic conditions improve, as a result of which the earth is covered with greenery. On land, the first species of cypresses and pines appear, as well as flowering plants. In the Mesozoic era, insects and flora begin to cooperate. During this period, the continents take on new shapes and sizes, as a result of their split, islands are formed. The Atlantic Ocean is growing in size, flooding large areas of land.
Cenozoic era
How much isyears is the period in which humanity lives? - people often ask this question. The Cenozoic era (it continues to this day) began about 66 million years ago. It was distinguished by the appearance of modern birds, mammals, angiosperms and, of course, humans. By the middle of the era, almost all the main groups of the kingdoms of wildlife had already formed. At this time, steppes and meadows, new types of grasses and shrubs appear. Also in nature, the main types of agrocenoses and biogeocenoses are formed. Man begins to adapt to the environment, to use nature to meet personal needs. It was people who later changed the organic world. The Cenozoic era consists of three periods: Paleogene, Neogene and Quaternary. It continues today.
The considered eras are divided according to climatic and geographical characteristics. But there are other systems of reckoning. For example, when saying “our era,” many people mean the stage that originates from the birth of Christ. Also, people single out the industrial, technotronic and other periods that distinguished themselves in some way, changed people's perception of the world, changed their attitude towards living organisms.
