Hyperplasia and hypertrophy are elements of phenotypic plasticity adjusting organ size and function. Because they are costly, we assume that they are beneficial. In this review, the authors discuss examples of tissue and organ systems that respond with plastic changes to osmotic stress to raise awareness that we do not always have sufficient experimental evidence to conclude that such processes provide fitness advantages. Changes in hydranth architecture in the hydroid Cordylophora caspia or variations in size in the anal papillae of (...) insect larvae upon changes in medium salinity may be adaptive or not. The restructuring of salt glands in ducklings upon salt‐loading is an example of phenotypic plasticity which indeed seems beneficial. As the genomes of model species are recently sequenced and the animals are easy to rear, these species are suitable study objects to investigate the biological significance of phenotypic plasticity and to study potential epigenetic and other mechanisms underlying phenotypic changes. (shrink)

Three decades ago, interactions between evolutionary biology and physiology gave rise to evolutionary physiology. This caused comparative physiologists to improve their research methods by incorporating evolutionary thinking. Simultaneously, evolutionary biologists began focusing more on physiological mechanisms that may help to explain constraints on and trade‐offs during microevolutionary processes, as well as macroevolutionary patterns in physiological diversity. Here we argue that evolutionary physiology has yet to reach its full potential, and propose new avenues that may lead to unexpected advances. Viewing physiological (...) adaptations in wild animals as potential solutions to human diseases offers enormous possibilities for biomedicine. New evidence of epigenetic modifications as mechanisms of phenotypic plasticity that regulate physiological traits may also arise in coming years, which may also represent an overlooked enhancer of adaptation via natural selection to explain physiological evolution. Synergistic interactions at these intersections and other areas will lead to a novel understanding of organismal biology. (shrink)

Non‐genetic forms of antimicrobial (drug) resistance can result from cell‐to‐cell variability that is not encoded in the genetic material. Data from recent studies also suggest that non‐genetic mechanisms can facilitate the development of genetic drug resistance. We speculate on how the interplay between non‐genetic and genetic mechanisms may affect microbial adaptation and evolution during drug treatment. We argue that cellular heterogeneity arising from fluctuations in gene expression, epigenetic modifications, as well as genetic changes contribute to drug resistance at different timescales, (...) and that the interplay between these mechanisms enhance pathogen resistance. Accordingly, developing a better understanding of the role of non‐genetic mechanisms in drug resistance and how they interact with genetic mechanisms will enhance our ability to combat antimicrobial resistance. Also see the video abstract here: https://youtu.be/aefGpdh-bgU. (shrink)