Origin of the Earth


 
 
Concept Explanation
 

Origin of the Earth

Origin Of The Earth: The origin of our earth took place around 4.6 billion years ago. Though the exact factors behind the process of its evolution are yet to be revealed, yet one of the most favoured theories suggests that it is the outcome of a star formation. Moreover, its evolution was not sudden, rather it was evolutionary Le. the earth had passed through several phases to attain its present form.

This entire evolutionary process of the earth can be studied with the help a Geological Timescale in which the entire history of the earth formation is divided into eras, periods, epochs and ages.Some of the most important landmarks in the evolution of earth are given below.

Pre-Cambrian Period: (From the birth of the earth to 500 million years ago) This period witnessed the cooling process of the earth from a hot gaseous to a molten state. With the further cooing of the outer thin solid crust the first ever rocks were formed on the earth's surface. But as the inner molten, liquid part was experiencing violent volcanic activity, so the rocks formed under such unsuitable conditions were completely unfossiliferous i.e, without life.

Palaeozoic Era: (From 570 million years ago to 225 million years ago): For the first time life appeared on the earth. The initial non-floral vegetation and invertebrates gradually were gradually followed by the vertebrates. This era is further divided into six periods:

Cambrian (570 million to 500 million years ago)

Ordovician (500 million to 440 million years ago)

Silurian (440 million on 395 million years ago)

Devonian (395 million years to 345 million years ago)

Carboniferous (345 million years to 28o million years ago) Most of the present day coal was formed in this period.

Permian (280 million years to 225-250 million years ago)

Mesozoic Era: (250 million years ago to about 65 million years ago) It is called the Age of Dinosaurs' because most dinosaurs developed, and went extinct, during that time.

Cenozoic Era meaning "new life" (from Greek kainos "new", and zoe "life") is the most recent of the three classic geological eras and covers the period from 65.5 million years to the present. It is marked by the Cretaceous-Tertiary extinction event at the end of the Cretaceous that saw the demise of the last non-avian dinosaurs and the end of the Mesozoic Era. The Cenozoic era is ongoing.

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