Origin of Life, Theories OfModern advances in biology, geology, chemistry, and astronomy have allowed us to elaborate models and hypotheses on the origin of life on Earth within the framework of the evolutionary theory. About four billion years ago, a rich inventory of organic compounds accumulated on the planet, as a product of volcanic, atmospheric, and cosmic chemistry. As chemical systems became increasingly more complex, a critical point was reached with the appearance of self-replicative polymers. This marks the possibility of optimizing abiotic systems by natural selection and historical contingency, which were added to the determinism of abiotic chemistry. A landmark of the origin of life was the articulation of suprachemical systems, such as self-reproductive vesicles, self-maintained chemical networks, and self-replicative polymers, under the conditions of the primitive Earth. Albeit most details remain unknown, the stepwise processes involved in the origin of life are scientifically comprehensible and experimentally reproducible.
The current controversies on the origin of life have deep historical and philosophical roots. In this sense, the scientific discussion of life emergence does not differ from other intellectual conflicts in biology and has developed through different, sometimes incompatible, models (Figure 1). Thus, the whole diversity of processes and scenarios, the abiotic generation of chemical complexity in the primitive Earth, both endogenous (atmosphere, sea surface, submarine chimneys) and exogenous (meteorites, comets, interstellar dust particles), and the role of minerals (catalysis and stability) and different energy sources (electromagnetic, chemical) invite us to an eclectic vision of the origin-of-life problem where the heterogeneity of mechanisms and conditions will be essential to assemble a coherent historical narrative.