Origin of Life

Abstract

Abstract Primitive life – defined as a chemical system capable of transfering its molecular information via self‐replication and also capable of evolving – probably originated about 4 billion years ago from the processing of organic molecules by liquid water. Organic matter might have been formed in the primitive atmosphere from methane or carbon dioxide but also in submarine hydrothermal vents. A large fraction of prebiotic organic material might have been brought by meteoritic and cometary dust grains decelerated by the atmosphere. Strategies to understand the origin of life include the reconstitution in the laboratory of an artificial life capable of self‐reproduction and evolution, the search for fossil traces of life in Archeaen sediments and the search for another example of natural life beyond the Earth, on Mars, Europa, Titan, Enceladus and exoplanets. Key Concepts: Life emerged about 4 billion years ago with organic molecules capable of self‐reproduction and of evolving in liquid water. A large fraction of the prebiotic organic material came from space. The reconstruction of life in a test tube lacks a simple synthesis of RNA. The very early fossil traces of life have been erased. The oldest accepted fossil traces of life are 3.45 billion years old. Mars harboured large oceans in the past and was therefore hospitable to life. Life may be present within the Europa's ocean. Organic chemistry is universal. Life may therefore arise on appropriate extrasolar planets.