abiogenesis

Abiogenesis, also known as the origin of life, is the natural process by which living systems arise from nonliving matter. It explores how the first replicating, metabolizing entities emerged on the early Earth and distinguishes itself from biogenesis, the reproduction of existing life.

Research has explored numerous pathways. Experiments in prebiotic chemistry demonstrate that simple inorganic compounds can yield amino acids, nucleotides, and lipids under plausible early Earth conditions. The exact environmental context and pathways remain uncertain, and many scientists distinguish between stages such as the formation of organic molecules, the assembly of polymers, the development of membrane-bound compartments, and the emergence of self-replicating systems.

Major conceptual frameworks include the metabolism-first hypothesis, which posits self-sustaining chemical networks; the RNA world hypothesis, proposing RNA molecules that stored information and catalyzed reactions; the lipid world or protocell models, emphasizing compartmentalization; and hydrothermal-vent theories, which locate the origin of life at alkaline or volcanic vents with natural catalytic surfaces and chemical disequilibria.

A widely cited sequence posits a progression from small organic molecules to polymers, then to protobionts with primitive metabolism, followed by self-replication and genetic inheritance leading to cellular life and the last universal common ancestor (LUCA). Still, no consensus defines the exact steps, timing, or environmental setting of abiogenesis.

Current research is interdisciplinary, combining chemistry, molecular biology, geology, and computational modeling. Advances continue to illuminate plausible prebiotic pathways and testable scenarios, while direct observational evidence for the transition from chemistry to biology remains elusive.