by George Musser
It didn’t take long for the recent Foundational Questions Institute conference on the nature of time to delve into the purpose of life. “The purpose of life,” meeting co-organizer and Caltech cosmologist Sean Carroll said in his opening remarks, “is to hydrogenate carbon dioxide.” Well, there you have it. Carroll is one of the most reflective scientists I know and would never claim to reduce all of human existence to molecular disequilibrium. Still, it’s nice to know your place in the grand scheme of things. The FQXi meeting had much to say about where we came from—and where we’re headed.
Last year, Carroll blogged the backstory of where his purpose-of-life line came from. He had bumped into Mike Russell of JPL, an expert on the origin of life, on an airplane and got to chatting about the role that living things play in the geochemical cycles of our planet. Russell was on hand at the FQXi conference, too, and elaborated on his engrossing thesis tracing our descent to inorganic chemical reactions.
In Russell’s picture, the primeval Earth looked uncannily like a giant bacterium. At the seafloor, in spots like the Lost City hydrothermal vents, the chemically reduced interior met the oxidized exterior, creating a state of chemical disequilibrium. Hydrogen bubbling up from the interior sought to combine with carbon dioxide dissolved from the atmosphere to form methane, but this reaction has a bottleneck because intermediate stages such as formaldehyde require an input of energy (see this helpful graph). A geochemical reaction known as serpentinization can push through the bottleneck, using metals such as iron as catalysts, but biological reactions are more efficient, and Russell mapped out a series of steps whereby serpentinization would evolve into membrane-encased cells.
Evolution at this stage was not by natural selection, but by the spontaneous generation of complexity; the Darwinian version came later as information-bearing molecules arose. The scenario is commonly referred to as “metabolism-first” as opposed to “genetics-first.” It is the protobiological version of the principle that the way to a man’s heart is through his stomach.
The process would have given birth to two of the three kingdoms of life, bacteria and archaea. Russell suggested that life might have arisen multiple times on Earth and, indeed, on any planet with similar chemical imbalances. Phylogeny replicates geology.
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Photo of Lost City hydrothermal field, courtesy of NOAA
It didn’t take long for the recent Foundational Questions Institute conference on the nature of time to delve into the purpose of life. “The purpose of life,” meeting co-organizer and Caltech cosmologist Sean Carroll said in his opening remarks, “is to hydrogenate carbon dioxide.” Well, there you have it. Carroll is one of the most reflective scientists I know and would never claim to reduce all of human existence to molecular disequilibrium. Still, it’s nice to know your place in the grand scheme of things. The FQXi meeting had much to say about where we came from—and where we’re headed.
Last year, Carroll blogged the backstory of where his purpose-of-life line came from. He had bumped into Mike Russell of JPL, an expert on the origin of life, on an airplane and got to chatting about the role that living things play in the geochemical cycles of our planet. Russell was on hand at the FQXi conference, too, and elaborated on his engrossing thesis tracing our descent to inorganic chemical reactions.In Russell’s picture, the primeval Earth looked uncannily like a giant bacterium. At the seafloor, in spots like the Lost City hydrothermal vents, the chemically reduced interior met the oxidized exterior, creating a state of chemical disequilibrium. Hydrogen bubbling up from the interior sought to combine with carbon dioxide dissolved from the atmosphere to form methane, but this reaction has a bottleneck because intermediate stages such as formaldehyde require an input of energy (see this helpful graph). A geochemical reaction known as serpentinization can push through the bottleneck, using metals such as iron as catalysts, but biological reactions are more efficient, and Russell mapped out a series of steps whereby serpentinization would evolve into membrane-encased cells.
Evolution at this stage was not by natural selection, but by the spontaneous generation of complexity; the Darwinian version came later as information-bearing molecules arose. The scenario is commonly referred to as “metabolism-first” as opposed to “genetics-first.” It is the protobiological version of the principle that the way to a man’s heart is through his stomach.
The process would have given birth to two of the three kingdoms of life, bacteria and archaea. Russell suggested that life might have arisen multiple times on Earth and, indeed, on any planet with similar chemical imbalances. Phylogeny replicates geology.
Read more:
Photo of Lost City hydrothermal field, courtesy of NOAA
