Earliest Traces as a Window on Life’s Origins

Life is the outcome of a complex network of chemical reactions and molecular interactions that emerged on Earth once primitive chemical automata could self-assemble in such a way that enabled them to self-reproduce and evolve. Yet exactly how, where and when life first ap-peared on our planet remain unknown. Various lines of evidence from traces of early life preserved in the geological record provide fundamental though rudimentary insight into life’s origins, since the oldest fossils rec-ord the nature of life more than half a billion years after it emerged on Earth. In spite of the chemical enigmas of the earliest life and its limited record, characterization of the various classes of biosignatures indicative of life in a geological context provides some guidance as to the nature of the earliest habitats and may aid those seeking to reveal the secrets of life’s origins.