Explaining the Origin of Life: What's the Question?

Abstract

The attempt to understand how and why Life emerged on Earth has been an approachable scientific question since the 1930s.  However, what we think that question is, and what counts as an answer, have continually changed as our understandings of biology and of planetary and space chemistry have repeatedly been overturned.  In this talk I will review four approaches to the problem of life's origin, each anchored in a paradigm-changing discovery about nature but also to some extent reflecting traditional viewpoints from different disciplines.  One approach focuses on the molecules of life and how to make them.  A second emphasizes the capacity of Darwinian evolution to shape matter, and the particular role of nucleic acids in carrying the evolutionary process on Earth.  A third emphasizes the intricate embedding of the biosphere within geochemistry and planetary energetics, and interprets the invariance of these relations over geological timescales as evidence of constraints on the possibilities for both living matter and evolution.  The fourth approach, emphasizing the problem of Life’s robustness, is still mostly passed over both in biology and in Origin of Life, but lessons learned in physics about the hierarchy of matter suggest that it is as fundamental as the other three.  From each new point of view, the requirements for an explanation of Life's emergence have changed.  Regarding them together, we can arrive at a provisional definition of the nature of the living state that is at once commonsense, but surprisingly far-removed from the definitions that were thought to be adequate a century ago.

Biography

Eric Smith studies the origin of life from a joint perspective in biochemistry and microbiology, geochemisty, and statistical physics.  He was educated in high-energy theory at the University of Texas until 1993, and since then has worked in a variety of areas at UT, the Los Alamos National Laboratory, and since 2000, at the Santa Fe Institute in northern New Mexico.  Smith’s work at SFI reflected the Institute’s broad interest in common motifs in complex systems, and included evolutionary dynamics and non-equilibrium thermodynamics, but also game theory, economics, and linguistics.  Starting in 2007 he participated in an NSF-sponsored project to understand the emergence of life reaching from geochemistry to regularities in the genetic code.  That project brought together a collaboration of geochemists, biochemists, molecular biologists and microbiologists, and physicists who remain his working partners to this day, and who have shaped his view of the nature of life and the problem of its origin.  In 2015, Smith joined the Earth-Life Science Institute at Tokyo Institute of Technology as a Principle Investigator, and later that year joined the Biology Department at Georgia Tech, where he is a member of Frank Rosenzweig's NASA Astrobiology Institute node on major evolutionary transitions.  He recently co-authored, with Harold Morowitz, a book “The Origin and Nature of Life on Earth: The Emergence of the Fourth Geosphere”, which was meant to gather the complicated and diverse landscape of ideas and literature needed to study the origin of life under a unifying narrative, in an effort to make the topic more accessible to researchers wanting to enter the field.