Abstracts
- Donna G. Blackmond
- David Catling
- Gerald F. Joyce
- Scott M. McLennan
- Martin Schoonen
- Sara Seager
- Lucy M. Ziurys
Donna G. Blackmond
“Physical and Chemical Models for the Origin of Biological Homochirality”
The description of Louis Pasteur meticulously separating mirror-image crystals using a magnifying glass and a needle is many a scientist’s first introduction to the fascinating subject of chirality and its importance to life on Earth. This lecture explores our work in developing models from both a chemical and a physical basis and aims to rationalize the evolution of single chirality in biological molecules.
David Catling
“Evolution of Atmospheres on Habitable Planets”
A key question for the origin and evolution of life is what makes a planet habitable. Earth's surface is stunningly different from the surfaces of its apparently lifeless neighbors, Mars and Venus. Yet when the solar system formed, Earth was surely dead and barren. I will address the question of how the evolution of planetary atmospheres affects whether a planet’s surface is conducive to life or not.
Gerald F. Joyce
“Directed, Continuous, and Self-Sustained Evolution of RNA Enzymes”
It is likely that an RNA-based genetic system preceded the DNA and protein-based system that has existed on Earth for the past 3.5 billion years. Through methods of in-vitro evolution, a variety of RNA enzymes have been developed, including those that catalyze the RNA-templated joining of RNA. Two such enzymes have been made to evolve continuously in a common reaction mixture. Another is able to produce additional copies of itself by joining two component oligonucleotides. An optimized form of the latter RNA enzyme was converted to a cross-catalytic format that allowed it to undergo sustained exponential amplification in the absence of proteins.
Scott M. McLennan
“The Sedimentary Cycle of Mars and Its Astrobiological Implications”
Mars has had a dynamic sedimentary rock cycle for at least the past four billion years. Throughout most of that time, surficial processes, including aqueous alteration and groundwater diagenesis, appear to have been dominated by relatively acidic conditions, with pH commonly less than about 4–5, and to have taken place in environments that were highly water-limited. Such environments provide many serious challenges for life to originate and thrive.
Martin Schoonen
“Minerals, Radicals, Prebiotic Chemistry, and the Emergence of Oxygenic Photosynthesis”
This talk will explore the possible role minerals may have played in prebiotic chemistry. The formation of mineral-induced radicals and their possible role in promoting the evolution of oxygenic photosynthesis on early Earth will be discussed in some detail.
Sara Seager
“Extrasolar Planets and the Search for Habitable Worlds”
For centuries people have wondered about the existence of life on other worlds. Now that more than 250 exoplanets are known to orbit nearby stars, we may be closer to answering this question.
The race to find habitable exoplanets has accelerated with the realization that big Earth’s orbiting small stars can be both discovered and characterized with current technology. Because conventional ideas about the search for life on exoplanets have focused on Earth-twins orbiting sun-like stars, we must take new directions if we want to recognize a habitable planet in an environment so different from our own.
Lucy M. Ziurys
“Prebiotic Chemistry in Space: Setting the Stage for the Evolution of Life”
To date, more than 135 different chemical compounds have been identified in interstellar space, the majority of which contain carbon. In fact, organic (such as carbon-containing) compounds are routinely found in only two areas of the universe: Earth and interstellar gas clouds. The history of carbon—from its synthesis in the interiors of stars, its incorporation into interstellar molecules, and then to its exogenous delivery to Earth via meteorites, comets, and dust particles—suggests there is a connection between organic chemistry in space and terrestrial living systems. Hence, the origins of life may be traced to gas-phase interstellar synthesis.
