✳️Fossils✳️

anyelinasc (56)in Steem-Science • 2 years ago

🔶The age of the earth🔶

According to the most recent calculations, the age of the earth can be estimated at approximately 5,000 million years. From its very origin, the earth has undergone a series of changes that little by little made possible the appearance of primitive living beings. At first life was impossible due to the unfavorable environmental conditions (excessive temperature) that prevailed on the earth, since it was an incandescent mass. But as conditions became more suitable for life, the first forms of life began to appear. For the study of the history of the earth, it has been divided into geological eras. When speaking of a geological era we must understand a very long period of time (millions of years), before which the years of human history hardly represented a very short time. These geological eras are: Azoic, Precambrian, Paleozoic, Mesozoic and Cenozoic.

🔶The geological eras🔶

🔹Era Azoica: when the earth separated from the sun the environmental conditions prevented you from giving you a way of life. This was roughly 3 billion years old. During it the burning mass (earth) begins to cool little by little. One part forms an incandescent liquid mass that cools and the other remains in gaseous form. As the liquid part cools, it creates a solid mass that forms the earth's crust.

🔹Era Precambrian: in it there are signs of life. It lasted about 600 million years. It is distinguished by seismic and volcanic activity, which causes the shape of the mountains. Fossils have been obtained that demonstrate the presence of small and poorly evolved living beings.

🔹 Paleozoic Era: Lasts approximately 1.8 billion years. In the beginning of this era fossils abound that are mostly seaweed. The weather was very hot and humid. Plant life passes from water to land. Plants without flowers appear, which reach maximum development with arborescent fern forests. Animal life at the beginning is represented by protozoa, corals, sponges. But, little by little other animals such as insects, spiders, amphibians, and lungfish appear.

🔹 Mesozoic Era: (Age of reptiles), lasts approximately 270 million years. At first the continents do not present many elevations, later the mountains, lakes, and lagoons appear. Plant life continues to evolve; large ferns disappear and flowering plants make their appearance. Animal life reaches a great development, as the great reptiles that dominate the Earth appear: dinosaurs, pterosaurs, etc. The first mammals appear.

🔹Cenozoic era: (Age of mammals), it lasted approximately 70 million years. It is the age of mammals, although all beings evolve at the same time as insects, birds, or plants. The climate is constantly changing. In the most recent stage of this era, in the so-called Quaternary period, man appears.

🔶What is a fossil?🔶

If an organism dies when it is trapped by strata and rocks, it will leave its mark in that place or its shape will be engraved on some rock.

Fossil is any remnant or impression of a plant or animal, which is found under the earth's crust.

We can distinguish two types of fossils:

🔹 Fossils that contain the whole or part of the living being.

🔹 Fossils that show us only the shape of the living beings that shaped it.

🔶Importance of fossils🔶

Fossils allow us to show that the earth has undergone changes since its appearance. Likewise, life has passed through various stages and some species disappeared and were replaced by others.

Paleontology is the science that studies fossils. Through this study, the succession of plants and animals that have populated the earth can be established. This also allows us to know the evolution of living beings through time. By studying fossils we can reach the following conclusions.

🔹 The forms of life, both animal and plant, have varied according to the different geological eras.

🔹 Each geological era is characterized by the predominance of a certain group of living beings.

🔹The appearance of species occurs beginning with the most primitive forms and continuing with the most evolved ones.

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