Question

The concept of chemical evolution is based on -
(A)- Possible origin of life by combination of chemicals under suitable environmental conditions.
(B)- Crystallization of chemicals.
(C)- Interaction of water, air and clay under intense heat.
(D)- Effect of solar radiation on chemicals.

Answer 1

Hint: The chemical evolution is the formation of complex organic molecules from simpler inorganic molecules through chemical reactions in the oceans during the early history of the Earth. It is the first step in the development of life on this planet. The period of chemical evolution didn’t last more than a billion years.


Complete step by step answer:
To understand the basic concept of chemical evolution, we first have to understand what is chemical evolution, how and when it occurs, what does different theory say about it etc.
The name of this theory itself says that the evolution of life was through chemicals. Oparin and Haldane were two peoples who gave this theory which proposed that the first form of life could have come from preexisting nonliving organic molecules and that formation of life was preceded by chemical evolution. Oparin’s theory is also known as artificial synthetic theory because it is based on Artificial synthesis of preexisting organic molecules.
The most important point in this theory is that the first life was originated in the oceans, also at that time volcanic eruptions, earthquakes were common so the percentage of oxygen in the atmosphere were very low which results in reducing atmosphere of earth so the first life which was formed was in absence of oxygen or we can say that the process was anaerobic. The energy required for them to initiate the reaction were provided by volcanic eruptions, lightning etc.
This evolution was occurred in different stages and they are as follows-
-The atomic stage – Most of the elements were first present in simple stages like $$H_2$$, $$N_2$$ etc. and the most abundant of them was $$H_2$$.
- Molecular stage – It explains the origin of molecules and simple inorganic compounds. It is also said that the first molecular compounds formed were probably water and ammonia.
- Origin or early compound – First organic compound formed was methane.
According to the above explanation, now it is clear that this theory is based on the reaction of different elements or compounds under suitable conditions i.e. temperature, pressure etc.


Therefore, the correct answer is (A)- Possible origin of life by combination of chemicals under suitable environmental conditions.



Note: You might get this theory explained in a different fashion by a different person. Remember that this is only a theory and there is no concrete proof of it happening or the order that it happened. There are also different peoples who gave a different theory but there are many similarities in their theories and the basic idea is already explained above.