A new theory of the multiple origins of life

The history of life on Earth has often been compared to a four billion year old torch relay. A flame, lit at the beginning of the chain, continues to transmit life in the same form all the way to the bottom. But what if life were best understood by the analogy of the eye, a converging organ that evolved from independent origins? What if life evolved not just once, but several times independently?

In a new article published in the Journal of Molecular Evolution, Santa Fe Institute researchers Chris Kempes and David Krakauer argue that to recognize the full range of life forms we need to develop a new theoretical framework.

In their three-level framework, Kempes and Krakauer call on researchers to consider, first, all the space of materials in which life might be possible; second, the constraints that limit the universe of possible life; and, third, the optimization processes that lead to adaptation. In general, the framework views life as adaptive information and adopts the analogy of calculus to capture the processes essential to life.

Several important possibilities emerge when considering life in the new setting. First, life has its origin multiple times – some apparent adaptations are actually “a new form of life, not just an adaptation,” Krakauer explains – and it takes on a much wider range of forms than conventional definitions allow.

Culture, IT and forests are all forms of life in this setting. As Kempes explains, “human culture lives on matter of spirit, just as multicellular organisms live on the matter of unicellular organisms.”

When researchers focus on the life traits of isolated organisms, they often overlook the extent to which the life of organisms depends on entire ecosystems as fundamental material, and also ignore the ways in which a living system can be more. or less alive. In the Kempes-Krakauer framework, on the other hand, another implication appears: life becomes a continuum rather than a binary phenomenon. In this vein, the authors point to a variety of recent efforts that quantitatively place life on a spectrum.

By taking a broader view of the principles of life, Kempes and Krakauer hope to generate more fertile theories for studying life. With clearer principles for finding life forms, and a new range of possible life forms emerging from new principles, we will not only clarify what life is, Krakauer explains, we will also be better equipped “to build devices for finding life, “to create it in laboratories, and to recognize how much of the life we ​​see is alive.