Current theories about the origin and history of life on Earth are based on the assumption that life arose at a given time on our planet and from then on it would have diversified and expanded to give rise to all current biodiversity. Now, Chris Kempes and David Krakauer, scientists from the Santa Fe Institute (United States) propose a new theoretical framework according to which life could have evolved several times independently.
In an article published in the scientific journal Journal of Molecular Evolution , the researchers argue that, in order to be able to recognize and understand the full range of life forms, we must develop a new theoretical framework that they explain with the analogy of the eye. It is known that this is a convergent organ that evolved from independent origins , and the authors propose that something similar would have happened with the different forms of life.
This theory consists of a three-layer framework. First, the complete space of materials in which life would be possible (genome and cells). Second, the restrictions that limit the universe of possible life, for example energy requirements. And finally, the role optimization processes that drive adaptation. In general, the framework views life as adaptive information and adopts the analogy of computation to capture the core processes of life. In this way we speak of the origin of the hardware (physical substrate) and the software (evolved function)
A new conceptual framework
When we consider life in this new theoretical framework, several possibilities emerge. In the first place, life could have originated several times, since some adaptations would not be such, but new forms of life.
According to the authors, when researchers focus on the life traits of individual organisms, they often neglect to what extent the life of organisms depends on entire ecosystems as their fundamental material, and they also ignore the ways in which a life system can be more or less alive. In the Kempes-Krakauer framework, on the contrary, another implication appears: life becomes a continuum rather than a binary phenomenon. In this regard, 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,” explains Krakauer, “we will also be better equipped to build devices to find life and even to create it artificially ”.
Text: Santa Fe Institute (USA)
Referencia: Kempes, C.P., Krakauer, D.C. The Multiple Paths to Multiple Life. J Mol Evol 89, 415–426 (2021). https://doi.org/10.1007/s00239-021-10016-2
