The r/K system and its effects: from evolution to medicine

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講演要旨

Among species, reproductive strategies are related to food availability. K-selected species (e.g. top predators - wolves) constantly struggle to find/catch food. Thus, K-selected species typically exhibit long lifespan and low fecundity. On contrary, r-selected species (e.g. preys - rabbits) have food in abundance. Thus, to optimize the available resources, r-selected species exhibit high fecundity (exponential growth) and are short-lived. Interestingly, within species we can also observe the same r- and K- reproductive strategies. Famine triggers a synchronized cascade of distinct pathways that decrease fecundity and maximize lifespan. This is equivalent to a K-program generating a K-phenotype. Inversely, ad libitum diet triggers a synchronized cascade of distinct pathways that maximize fecundity and minimize lifespan. This is equivalent to an r-program generating an r-phenotype. Therefore, universally, species have r/K-selected programs/phenotypes to better adapt to specific food conditions (named r/K system). We propose that long-term adaptation in a specific food condition is sufficient to explain all aspects of evolution in a single theory. This perspective has significant impact in several scientific fields. We describe the reasons and the genetic basis for the evolution of lifespan, fecundity, novelty, complexity and prey-predator relations. Furthermore, we highlight how this new perspective can benefit medical research.