It is presumed that the universe came into existence with a single titanic explosion called 'THE BIG BANG THEORY' about 15 billion years ago. With the Big Bang, all the matter and tremendous energy came into existence. The Big Bang led to the formation of variously sized fire balls. These fire balls had tremendous amount of heat in them. These fragments cooled in a period of time and gave rise to many more celestial bodies. In due course of time our Solar System consisting of our Sun and the planets. The Earth is presumed to have originated about 4.6 billion years ago.
Initially the earth was a fire ball. This fire ball cooled down. This cooled chunk then formed methane around itself. Methane is the gas due to which human life is possible. After methane ammonia was formed. And eventually many other gases came into being. These gases supported human life.
The origin of life is also called 'PROTOBIOGENESIS' . It is clear that life came into existence from the non-living substances of the primordial earth about 3 billion years ago.
To explain the origin of life there have been many theories-
1.Theory of special creation:The Spanish monk Father Sudrez proposed the theory of special creation. According to the theory all the living beings on the earth were created by Gid or a supernatural power
2.Cosmozoic theory:Also known as panspermia theory, it was given by Richter in 1865. According to this theory, life on earth came from a distant planet in the form of spores or micro-organisms. It was called cosmozoa or panspermia which were preserved inside meteorites. These meteorites struck the earth to release the cosmozoa and helped in development of living organisms.
3.Theory of abiogenesis:It is also called theory of autobiogenesis. According to this theory, life on earth originated from non-living material spontaneously, without any interruptions. It was also supported by Aristotle.
Louis Pasteur disproved the theory of spontaneous generation and gave explanation that life originated only from pre-existing life.
4.Theory of biogenesis: Francisco Redi, Spallanziand Louis Pasteur are the three famous scientists who conducted classical experiments to disprove the theory of abiogenesis. According to biogenesis, living organisms are always produced from pre-existing living forms by reproduction and not by non-living matter.
Among the various theories explaining the evolution of life The Theory Of Evolution is widely accepted:
According to this theory, a life substance appeared on earth in water. During a course of time, this living substance developed into a unicellular form of life. Then some gradual and orderly changes took place in this unicellular form and it developed into a multicellular forms of greater and greater complexity. Then behavioural patterns also gradually underwent many changes. These changes were slow and sequential. It took a prolonged period of nearly 300 crores of years. These changes and development of living things took place in all aspects and that gave way for many different kinds of living things to come into existence. Hence this process is called the evolution of life on earth, which is also referred to as organic evolution.
Initially the earth was a fire ball. This fire ball cooled down. This cooled chunk then formed methane around itself. Methane is the gas due to which human life is possible. After methane ammonia was formed. And eventually many other gases came into being. These gases supported human life.
The origin of life is also called 'PROTOBIOGENESIS' . It is clear that life came into existence from the non-living substances of the primordial earth about 3 billion years ago.
To explain the origin of life there have been many theories-
1.Theory of special creation:The Spanish monk Father Sudrez proposed the theory of special creation. According to the theory all the living beings on the earth were created by Gid or a supernatural power
2.Cosmozoic theory:Also known as panspermia theory, it was given by Richter in 1865. According to this theory, life on earth came from a distant planet in the form of spores or micro-organisms. It was called cosmozoa or panspermia which were preserved inside meteorites. These meteorites struck the earth to release the cosmozoa and helped in development of living organisms.
3.Theory of abiogenesis:It is also called theory of autobiogenesis. According to this theory, life on earth originated from non-living material spontaneously, without any interruptions. It was also supported by Aristotle.
Louis Pasteur disproved the theory of spontaneous generation and gave explanation that life originated only from pre-existing life.
4.Theory of biogenesis: Francisco Redi, Spallanziand Louis Pasteur are the three famous scientists who conducted classical experiments to disprove the theory of abiogenesis. According to biogenesis, living organisms are always produced from pre-existing living forms by reproduction and not by non-living matter.
Among the various theories explaining the evolution of life The Theory Of Evolution is widely accepted:
According to this theory, a life substance appeared on earth in water. During a course of time, this living substance developed into a unicellular form of life. Then some gradual and orderly changes took place in this unicellular form and it developed into a multicellular forms of greater and greater complexity. Then behavioural patterns also gradually underwent many changes. These changes were slow and sequential. It took a prolonged period of nearly 300 crores of years. These changes and development of living things took place in all aspects and that gave way for many different kinds of living things to come into existence. Hence this process is called the evolution of life on earth, which is also referred to as organic evolution.
