Theory of Evolution
Evolution has taken place over millions of years and is responsible for all the living things on Earth today. There are different views and theories about the origin of life and the evolutionary process.
It is not possible to be certain how life on Earth began. We do know that:
Through the study of simple organisms and the chemistry of living things, we can develop scientific theories about how life on Earth began. The main theory is that living things developed from molecules that could replicate, or copy, themselves, rather like DNA [DNA: The material inside the nucleus of cells, carrying genetic information. DNA stands for Deoxyribonucleic Acid. ] does.
There are two possible origins for these replicating molecules:
Over many millions of years these molecules joined with other molecules, becoming gradually more complex and dependent on each other. The process of evolution by natural selection eventually led to all of the different living things that we see on Earth today.