As per the findings in evolutionary biology, the universe, earth and the variety of life forms are the results of evolution. It deals with the origin of life on earth. The conditions and life forms of earth were entirely different from what we see today. Everything evolved from one form to another for a better chance of survival. Here we will discuss the origin of life on earth in details.
Origin of Universe
Origin of life begins with the origin of the universe. The universe, an old vast and empty space comprising of galaxies, originated around 20 billion years ago. There was nothing but blackness filled with gas and dust. The Big Bang Theory is the most accepted theory regarding the origin of earth and life forms in it. According to the theory, the universe is a result of a massive explosion which occurred 20 billion years ago. Whether it is a hypothesis or a fact, a new universe was formed. The atmospheric condition after the explosion became more stable. The temperature reduced and gasses like hydrogen and helium formed which led to the formation of galaxies of today.
Later, after 10 billion years, the earth was formed which was covered by water vapor, methane, carbon dioxide, and ammonia. There was no atmosphere but only gasses and moisture. The powerful rays of the sun stimulated and hastened the evolution. By making and breaking of bonds between gas molecules, earth came out with a new face. After millions of years i.e., once earth atmosphere was stabled, the first life on earth came to exist (around 4 million years ago). There began the story of the origin of life on earth.
Origin of Life
There were lots of hypothesis regarding the origin of life on earth. Certain experts suggested that life came from outer space as spores while another group explained that life came from a non-cellular component such as decaying matters like mud. The latter theory was known as the theory of spontaneous generation, which was discarded later.
Oparin and Haldane suggested that life originated from non-living organic molecules like proteins and RNA. This was followed by the theory of chemical evolution which suggested that atmospheric conditions of earth led to the formation of organic molecules from inorganic molecules. Few scientists conducted experiments regarding the same. However, once the first life came into existence, they started to evolve in different ways and forms. This laid a stepping stone to the theory of evolution.
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