The origin of life has been a subject of speculation in all known cultures and indeed, all have some sort of creation idea that rationalizes how life arose. In the modern era, this question has been considered in terms of a scientific framework, meaning that it is approached in a manner subject to experimental verification as far as that is possible. Geological formations contain a wealth of information concerning the origin of life on Earth and provide abundant evidence of the relationships between physical and biological evolutionary processes.

Radioactive dating provides evidence that that Earth formed at least 4.6 billion years ago. Yet, the earliest known fossils of microorganisms, similar to modern bacteria, are only about 3.5–3.8 billion years old. The earlier prebiotic era (i.e., before life began) left no direct record, and so it cannot be determined from the geologic record exactly how life...