Chemical Evolution and Natural Processes

One explanation is that life emerged through a long sequence of ordinary chemical processes operating on the early Earth.

On this view, simple chemicals produced increasingly complex organic compounds. Environmental conditions concentrated some of those compounds and promoted further reactions. Molecules capable of catalysis, replication, compartmentalization, and energy use eventually became connected into systems upon which natural selection could act.

Experiments have demonstrated important parts of this general picture. Researchers have produced biologically relevant organic compounds under plausible prebiotic conditions, formed polymers through nonbiological chemistry, constructed membrane vesicles, developed catalytic RNA molecules, and investigated several mechanisms of molecular replication.

What has not been experimentally reconstructed is the complete transition from nonliving chemistry to an autonomous system capable of sustained Darwinian evolution.

Chemical evolution therefore provides a broad natural framework for origin-of-life research while leaving important questions about the sequence and integration of the required processes unresolved.