Today we see innumerable varieties of insects, birds and animals besides human beings on the earth. Similarly there are various kinds of trees, plants and bushes. All of them come under the category of living beings. Do you know how life started on the earth?
To study the origin of life on the earth, the scientists study the fossils of those animals, trees and plants which lived on the earth millions of years ago. Excavations carried out at various places on the earth have made available fossils, rocks and bones which throw a significant light on the existence of living beings of ancient times.
There are many theories about how life began on earth. Almost all religions teach that all forms of life were created by some divine or supernatural being or force. Another theory states that life originally came to earth from outer space through micro-organisms. Many biologists and bio-chemists believe that life developed from non-living materials.
However, scientific studies have revealed that life on the earth started with the unicellular organism called amoeba. This happened some 570 million years ago. From this very unicellular amoeba evolved the multi-cellular life on the earth. The first 345 million years saw the development of marine life. The subsequent 160 million years had the development of reptiles. In the last 65 million years, the evolution of mammals took place. Man’s birth is a phenomenon only one million year old.
It is observed from the study of the cells of plants and animals that they are made of proteins, carbohydrates, fats and many other substances. All these things must have been existing on the earth much before the origin of the unicellular life. Now the question arises: how did these substances which are so essential for life come to the earth? Recent studies have shown that these were formed by electric discharge.
Around 3500 million years ago, the earth’s atmosphere was full of ammonia, methane, hydrogen, water vapour etc. At that time the earth was very hot and the sky was overcast with clouds. Lightning and thunder were common occurrences. The electric discharge during the lightning led to the chemical combination of the molecules of these gases resulting in the formation of proteins, carbohydrates etc. which finally gave birth to the unicellular amoeba.
Even though we have been able to solve many mysteries relating to the origin of life on the earth, there are many more which are still needed to be looked into. For example, when atoms and molecules are lifeless, how come their combination creates life? What is it which enables a unicellular amoeba to produce a multi-cellular creature? We still have to find answers too many such complex questions.
