Question

What are the different theories about the origin of life?

Answer 1

The origin of life is also known as abiogenesis. It is a process in which life originates from non-living substances. These non-living substances are inorganic or organic matter.

Complete answer:
There are different theories given by scientists over the year about the origin of life. There is no single which is accepted for the origin of life. Before life forms existed on the Earth, the planet was inhabitable and consisted of several chemicals. After years of chemical reactions and evolution, the Earth becomes habitable for humans. Following are the theories on the origin of life:
Primordial Soup Theory:
In the 1920s, Oparin and Haldane had given primordial soup theory. According to this theory, lightning acts as the energy which converts the inorganic gases present in the Earth’s environment into organic matter such as amino acids. This organic matter later evolved to become a complex organism.
The Miller Experiment:
In 1953, Stanley Miller conducted an experiment which showed the condition of the primitive Earth billions of years ago. He sent the electrical charge to the flask which consists of a solution made from ammonia, water, methane, and hydrogen. The passage of the electric charge resulted in the formation of the amino acids. They conclude that inorganic chemicals converted into an organic substance which later evolved. This Miller experiment was based on the primordial soup theory.
RNA world:
In the 1980s, Altman and Cech suggested that RNA can act as a catalyst. They suggested that RNA act as both enzymes as well as hereditary material for the life form. The RNA system evolved and underwent natural selection to reach the advanced life form.

Note: This theory suggested that instead of growing from complex material such as RNA, the origin of life begins from the interaction of the smaller molecules. These molecules initiated the cycles of reaction. Over time, these simple molecules evolved into complex molecules.