Time line of evolution on earth.or evolution history of life on earth
~Time line of evolution on earth~
• History of Earth. is believed that the earth is originated about 5-6 billion years ago.
• earth was separated or cast off from the molten mass of extremely hot gaseous material.
• Initially, the earth was like a spinning ball of hot gases and vapours of various elements.
• Thearth was mperature of the earth was about 5000°C to 6000°C.
• However, st of the workers, now believe that earth's temperature was never hove 900°C As it was moving away from the sun, it was cooling wn gradually, the condensation of gases and elements begun and arious elements were arranged in a different stratum accordingly their density.
• The heavy elements like įron, nickel. etc.
settled own in the centre to form core of the earth; lighter elements such S silicon, Aluminium, formed the middle, while the lightest dements like hydrogen, helium, Carbon, Nitrogen, Oxygen, etc.
• were arranged on the outermost.
• At such a high temperature (900°C) these elements could not exist in their free state, but were combined among themselves or with metals forming oxides, carbides, nitrites, nethane, etc...
• About 3 billion years ago, the earth had a solid crust.
• This was erupted at many places due to volcanic activities, Eruption of volcanoes developed many crevices and mountains.
• Simultaneously,
• the condensation of the atmospheric water was took place and the steam; got condensed and back as rain.
• This was happening for many vears. After that the rain water filled the deeper surfaces of the earth's crust which led the Ocean formation.
• In the early days the oceanic water was alkaline.
• The primitive atmosphere of earth was devoid of free oxygen. On the earth, over the period of time, the land.
• water and suitable elements were formed in the atmosphere, Such changes occurred in composition of atmosphere and conditions of elements which favors the beginning of life.
• This is known as chemical evolution.
• Thus, physical, chemical and later on biological evolution occur on the earth.
History of Earth. Origin and evolution of Earth. Origin of Earth. History of human in earth. History of Earth life . History of evolution ofEarth.,
Time line of evolution on earth
Time line of evolution on earth.
Time line of evolution on earth
Time line of evolution on earth
Time line of evolution on earth
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