Question

Explain the most valid theory about the origin of life on earth.

Answer 1

1. The most widely accepted scientific explanation is the theory of chemical evolution, associated with Oparin and Haldane. It proposes that life arose gradually from non-living matter on the early earth.
2. Early earth had a hot environment and a different atmosphere from today’s. Simple substances in the atmosphere and oceans reacted, using energy from sources such as lightning and sunlight, to form simple organic compounds.
3. Over a long period, these compounds accumulated in water and combined into more complex molecules. Eventually, some molecules became organised into primitive, cell-like structures.
4. The earliest simple living organisms then appeared and, over millions of years, gave rise to the diverse forms of life on earth.
5. This theory explains the proposed origin of the first life; it is different from biological evolution, which explains how living organisms diversified after life had begun. The precise details of life’s origin remain under scientific investigation.