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. J. Photochem. Photobiol., A 49, 53 (1989). 8. doi:10.1126/science.1079894 , U. H. Wiechert. Science 298, 2341 (2002). 9. H. D. Holland. Geochem. News 100, 20 (1999). 10. doi:10.1126/science.1071184 , J. F. Kasting, J. L. Siefert. Science 296, 1066 (2002). 11. doi:10.1007/BF00926894 , J. Levine, T. Augustsson, M. Natarajan. Orig. Life Evol. Biosph. 12, 245 (1982). 12. doi:10.1023/A:1011895600380 , J. W. Delano. Orig. Life Evol. Biosph. 31, 311 (2001). 13. H. D. Holland. The Chemical Evolution of the Atmosphere and Oceans, pp. 29-127, Princeton University Press

5 CHEMICAL EVOLUTION When we try to pick out anything by itself, we find it hitched to everything else in the universe. — J O H N M U I R The initial billion or so years of cosmic history spawned formation of the first structural units of matter, the galaxies and the clusters in which they reside. The chemical inventory bequeathed, however, was decidedly meager: mainly hydrogen with a sprinkling of helium. We who would dare to recreate our past can, with hindsight, see both advantages and disadvantages to the early absence of chemical diversity. A

2 Chemical evolution The term evolution1 was used first in the field of biology at the end of the nine- teenth century. In the context of biology, evolution is simply the genetic change in populations of organisms over successive generations. Evolution is widely under- stood as a process that results in greater quality or complexity (a process in which something passes by degrees to a different stage, especially a more advanced or mature stage). However, depending on the situation, the complexity of organisms can increase, decrease, or stay the same, and all

2 Chemical evolution The term evolution was used first in the field of biology at the end of the nineteenth century. In the context of biology, evolution is simply the genetic change in popula- tions of organisms over successive generations. Evolution is widely understood as a process that results in greater quality or complexity (a process in which something passes by degrees to a different stage, especially a more advanced or mature stage). However, depending on the situation, the complexity of organisms can increase, decrease, or stay the same, and all three

Reviews in Mineralogy & Geochemistry Vol. 68, pp. 31-53,2008 Copyright © Mineralogical Society of America 4 Nucleosynthesis and Chemical Evolution of Oxygen Bradley S. Meyer Department of Physics and Astronomy Clemson University Clemson, South Carolina 29634, U.S.A. mb radie @ clemson. edu Larry R. Nittler and Ann N. Nguyen Department of Terrestrial Magnetism Carnegie Institute of Washington Washington, D.C. 20015, U.S.A. Scott Messenger Robert M. Walker Laboratory for Space Science NASA Johnson Space Center Houston, Texas 77058, U.S.A. ABSTRACT

3 edwin a. bergin THE CHEMICAL EVOLUTION OF PROTOPLANETARY DISKS 1. Introduction The origins of planets, and perhaps of life itself, are intrinsically linked to the chemistry of planet formation. In astronomy these systems are labeled protoplanetary disks—disks on the incipient edge of planet formation. For our Sun, the rotating ball of gas and dust that collapsed to a disk has been called the Solar Nebula. In this chapter I will attempt to explore the chem- istry of planet-forming disks from the perspective of knowledge gained from decades of solar system study

✦ ✦ ✦ ✦ ✦ C h a p t e r 9 the ChemiCal evolution of the early universe Our lives on Earth are in a constant state of motion, but taking a look at the celestial night sky, the stars and their positions seem to be static and permanent. The cosmos is not stationary, though, by any means, even though the timescales on which celestial objects move are gigantic compared to terrestrial and human ones. At the beginning of cosmic evolution, there were no stars. The Uni- verse was completely dark. Only gradually, starting a few hundred mil- lion years after

3 History of the climate system: the chemical evolution Under the evolution of the Earth and the climate system, we will simply understand the historical development from earliest times until the present. Theories for how the atmosphere and ocean formed must begin with an idea of how the Earth itself originated (Kasting 1993). 3.1 The prebiological period 3.1.1 Origin of elements, molecules, and the Earth Our galaxy is probably 13.8 ± 0.06 Gyr old (Bennett et al. 2013) and was formed by the hot big bang, assuming that the whole mass of the galaxy was concentrated

Prebiotic Syntheses and the Mechanism of Early Chemical Evolution Christian de Duve Introduction Fritz Lipmann wrote only one paper on the origin of life (1), but he apparently thought enough of it to include it with his autobiography (2). There are good reasons for this. It was, in fact, by reflecting on the origin of polypeptide synthesis that Lipmann was induced to undertake the work that he did with Wieland Gevers and Horst Kleinkauf on the synthesis of gramicidin S and later on that of tyrocidin (3,4). I will have more to say about this seminal