The Origin and Early Evolution of Life: Prebiotic Chemistry, the Pre-RNA World, and Time

Antonio Lazcano* and Stanley L. Miller† models incorporate high partial pressures of CO2 to raise the temperature of the Earth by a greenhouse effect *Departamento de Biologı́a Facultad de Ciencias and thus prevent the complete freezing of the oceans (Kasting, 1993). However, a frozen Earth has some adUniversidad Nacional Autónoma de Mexico Apartado Postal 70-407 vantages for prebiotic chemistry (Bada et al., 1994). But again, there is no direct evidence either way. In addition, Cd Universitaria México 04510, D.F. Mexico processes relevant to the origin of life may have taken place in environments different from the terrestrial aver†Department of Chemistry and Biochemistry, University of California, San Diego age, e.g., hot springs, eutectic sea water, or drying lagoons. La Jolla, California 92093-0506