Chemical Evolution

It is the scientific view of the origin of life on earth.

It explains that;

• Catalytic effect of lightning or some other catalysts brought together simple elements to form simple molecules such as water, ammonia and methane.
• Further combination of the simple molecules formed the complex, self-replicating compounds which resemble present day DNA or RNA which are the basic molecules of life.
• Successive replications of these DNA or RNA molecules gave rise to simple forms of the first living cells, which resemble the present day viruses, bacteria and protozoa.

This theory holds the following views;

1. Life came into existence through combination of simple chemical molecules.
2. The initial life forms were simple and have evolved over the years to form the present day complex organisms; principle of organic evolution.

The scientific evidence in the form of experiments, artefacts and fossils back up this theory.

Study Question

Distinguish between chemical and organic evolution

• Chemical evolution is the emergence of simple life forms from simple chemicals over a long period of time while
• Organic evolution is the emergence of more complex life forms from simple forms over a long period of time;