A CORE QUESTION IN ORIGINS OF LIFE RESEARCH IS HOW SIMPLE ORGANIC MOLECULES BECAME SELF-ORGANIZED INTO SYSTEMS THAT COULD BOTH SELFPROPAGATE AND EVOLVE. ANSWERING THIS QUESTION IS CRITICALLY IMPORTANT BOTH FOR MAPPING OUT THE CONDITIONS NEEDED FOR LIFE TO EMERGE AND FOR IDENTIFYING ESSENTIAL FEATURES OF LIFE THAT COULD SERVE AS BIOSIGNATURES OF LIVING SYSTEMS ON OTHER WORLDS. ONE POSSIBILITY IS THAT THE FIRST EVOLVERS WERE SELF-SUSTAINING (AUTOCATALYTIC) CHEMICAL SYSTEMS LOCALIZED ON MINERAL SURFACES AND COMPOSED OF MOLECULES THAT COULD CATALYZE EACH OTHER S FORMATION. MY STRATEGY TO EVALUATE THIS MODEL IS TO USE CHEMICAL ECOSYSTEM SELECTION (CES) AN ANALOG OF EXPERIMENTAL EVOLUTION IN WHICH CHEMICAL SYSTEMS ARE REPEATEDLY SELECTED FOR THEIR ABILITY TO COLONIZE NEW MINERAL SURFACES. THE APPROACH INVOLVES INCUBATING MIXTURES OF CHEMICAL INPUTS OR FOOD WITH MINERAL GRAINS AND PERFORMING SERIAL TRANSFERS TO SELECT FOR SPONTANEOUSLY-FORMED SURFACE-ASSOCIATED SYSTEMS THAT ARE BETTER AT BEING TRANSMITTED FROM GRAIN TO GRAIN. A KEY ADVANTAGE OF CES IS THAT LIFELIKE SYSTEMS ARE DETECTED BASED NOT ON THE APPEARANCE OF PARTICULAR CHEMICAL SPECIES BUT ON SYSTEMATIC CHANGES OVER TRANSFERS IN EMERGENT CHEMICAL PROXY TRAITS. I RECENTLY REPORTED THE RESULTS OF CES EXPERIMENTS CONDUCTED ON A SIMULATED PREBIOTIC SOUP INCUBATED WITH PYRITE WHICH YIELDED EVIDENCE OF COMPLEX DYNAMICS THAT ARE CONSISTENT WITH THE EMERGENCE OF LIFELIKE CHEMISTRY INCLUDING A DISTINCTIVE OSCILLATORY PATTERN SUGGESTIVE OF SEQUENTIAL FLUCTUATIONS IN CYCLES OF A DYNAMICALLY MAINTAINED CHEMICAL SYSTEM. IN ADDITION TO FURTHER CHARACTERIZING THE CHEMICAL BASIS OF THIS PUTATIVE LIFELIKE SYSTEM I PROPOSE DEPLOYING CES ON OTHERS CONDITIONS TO ASSESS WHETHER THE CURRENT CANDIDATE CONSTITUTES A RARITY OR REFLECTS A BROADER PHENOMENON. TO THIS END I WILL DEPLOY LONG-TERM CES EXPERIMENTS ON SIMPLER INPUTS MODELED AFTER RECENT COMPUTATIONAL ANALYSES OF PROTOMETABOLIC AND RADIOLYTIC CYCLES AND USE CHROMATOGRAPHY-MS TECHNIQUES TO ESTABLISH WHETHER SYSTEMIC CHANGES SEEN OVER SERIAL TRANSFERS MIGHT INDICATE SELF-PROPAGATION AND PRE-GENETIC EVOLUTION. FINALLY I WILL USE THE CES FRAMEWORK TO SEARCH FOR EVIDENCE OF LIFELIKE CHEMISTRY IN THE PRODUCTS OF CHEMICAL SYNTHESIS EXPERIMENTS CARRIED OUT UNDER TITAN HAZE CONDITIONS. COMPARING THE SYSTEM-LEVEL PATTERNS OBSERVED IN THESE EXPERIMENTS WILL ALLOW ME TO DISTINGUISH BETWEEN COMPLEX DYNAMICS THAT CONSTITUTE TRUE BIOSIGNATURES FROM THOSE THAT ARE FALSE POSITIVES IN THAT THEY CAN BE PRODUCED BY NON-LIVING PROCESSES. OVERALL THE PROPOSED EXPERIMENTS ARE EXPECTED TO PROVIDE MULTIPLE EXAMPLES OF CHEMICAL SYSTEMS THAT DISPLAY DYNAMIC PATTERNS RESEMBLING LIFE AND ADVANCE OUR UNDERSTANDING OF HOW READILY EVOLVABLE CHEMICAL SYSTEMS EMERGE AND WHERE THEY MIGHT ARISE IN THE UNIVERSE. THEREFORE THE PROPOSED RESEARCH ALIGNS WELL WITH NASA S PLANETARY SCIENCE OBJECTIVE 1.5 TO IMPROVE OUR UNDERSTANDING OF THE ORIGIN AND EVOLUTION OF LIFE ON EARTH TO GUIDE OUR SEARCH FOR LIFE ELSEWHERE.