image: Pawel Czerwinski/Unsplash

From the perch of modernity, it is tempting to envision the limbs of the tree of life as inevitable, a steady march toward existence from one generation to the next. Some branches in the tree are shorter than others, of course — tales of extinction, from the asteroid-blasted dinosaurs to the human-blasted passenger pigeon, offer a tragic alternative vision of what life on Earth could look like today. 

Perhaps even more tantalizing, however, are life’s near misses — the unformed pathways lurking in the shadows of evolution.

“Evolution is contingent,” explains SFI Professor Chris Kempes. “Sometimes it can ignore whole spaces of potential discovery.”

Kempes is co-organizing an August working group — the second in a series — focused on these spaces of undiscovered life. The meeting, “Feasible but Undiscovered Metabolisms II: Thermodynamics, Evolution, and the Origin of Life,” comprises a diverse group of origin-of-life researchers including theorists and experimentalists who study Earth history, fundamental thermodynamics, cell physiology, and genome evolution. 

“Part of what we’re doing in this workshop is to expand our knowledge of what is going on in our contemporary biosphere, but to also think outside it,” says co-organizer Shawn McGlynn, an Associate Professor at Tokyo Institute of Technology, Earth Life Science Institute. 

Specifically, the researchers are focused on metabolisms, or how organisms harvest energy from the surrounding environment. Metabolisms on Earth are diverse: plants photosynthesize, chemoautotrophs harvest energy from the Earth’s crust, and humans, like other heterotrophs, are powered by consuming other organisms. But known energetic pathways only represent a fraction of the metabolic pathways that exist — or could exist. One of the goals of the working group is to define, based on universal laws of physics and chemistry, the physical boundaries of life, on Earth and beyond.

“If we can understand the diversity of how life works, we’ll be in a better position to hypothesize about what life may have been like in deep time and to imagine possibilities for the future of life on Earth, or even life on other planets,” says McGlynn.

The meeting is the final event covered by the National Science Foundation Origins of Life Research Coordination Network grant. While the next steps for this work are undetermined, the group is discussing how to move forward and further the ideas that have come out of the five-year project.

Support from the National Science Foundation Grant Award 1745355 Convergence: Rules of Life - Research Coordination Network for Exploration of Life's Origins.