Adaptability Beyond Darwin: Microbial Evolution, Mitochondria, and the Thermodynamic Frontiers of Survival

Charles Darwin hypothesized that evolution is based on adaptations to a changing environment, and that organisms that developed even slightly favorable variations would ultimately be most likely to survive. This concept is clearly reflected in the life cycles of pathogenic species. While modern antibiotics, antiviral agents, and vaccines can successfully eliminate many pathogens and prevent infections, only susceptible strains are affected. Bacteria and viruses that can adapt and develop resistance mechanisms will survive and thrive in the absence of ongoing competition. We build on this framework by considering the evolutionary impact of microbial-mediated adaptations experienced by the host. For example, intracellular mitochondria, largely believed to be descendants of symbiotic ancestral bacteria, can be specifically targeted by viral pathogens. Taken one step further, we hypothesize that Darwinian theory may also apply to atoms and molecules, which are not “alive” by any conventional definition, but interact with one another and self-assemble according to the principles of thermodynamics that promote stability in defined environments. Building on these foundations, our hypotheses and conceptual framework will facilitate further exploration into the evolution of microbial mechanisms that modulate behavior, shape the development of the immune system, and promote host evolution.