The formation of complex organic molecules from simpler inorganic molecules through chemical reactions in the oceans during the early history of the Earth; the first step in the development of life on this planet. The period of chemical evolution lasted less than a billion years.
Note: Many of the steps in chemical evolution can now be reproduced in the laboratory.
Note: Some scientists believe that all or most of the Earth's original organic molecules were created in space and were brought to the Earth's oceans by meteorites.