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The Origins of Aging
Published in Shamim I. Ahmad, Aging: Exploring a Complex Phenomenon, 2017
Another important observation is that developmental programs are plastic; they only set the boundaries for the phenotypic characteristics of a given species. Within a species, there is considerable between-individual variation in morphology, behavior, and lifecycle stages. The molecular basis of this phenotypic plasticity is not understood although epigenetic mechanisms have been proposed as a possibility. However, there is still controversy as to whether epigenetic marks can be transmitted across generations (van Otterdijk and Michels 2016). Between-individual phenotypic variation is critical since it allows the species to adapt to and survive short-term environmental perturbations. Interestingly, large phenotypic plasticity has been described in clonal marine plants even though these organisms share a common genotype and have a low somatic mutation rate (Arnaud-Haond et al. 2012). It has been suggested that the particular genotypes retained by clonal organisms are ones that “encode” large phenotypic plasticity. Using this observation from clonal organisms, one could propose that during the evolution of species-specific developmental programs, only those programs that confer significant phenotypic plasticity are retained.
Climate change, uncertainty and allostatic load
Published in Annals of Human Biology, 2019
D. E. Crews, N. C. Kawa, J. H. Cohen, G. L. Ulmer, A. N. Edes
As a human response to environmental stressors, allostasis has been commonly explored by human biologists and physiological anthropologists under the rubric of human adaptability research (see Baker 1984; Little 2010; Edes and Crews 2017; Crews 2018). To maintain optimum somatic function, organisms must constantly adjust their physiology to current environmental and social stressors. Examples abound in human physiology. Cortisol, blood pressure and body temperature normally reach their nadirs while we sleep, rise upon awakening and respond to daily stressors in-between. Blood pressure, sweating and glucose mobilisation increase not only upon commencement of strenuous physical activity, but even as such activities are contemplated. Whether it be fleeing a predator, chasing down prey, socially competing with or physically fighting a conspecific, stressful experiences imprint cognitive function, modulating the timing and strength of future allostatic responses. Humans constantly adjust neurological and physiological functions and circulating hormone titres as they respond to changes small and large in their environmental and sociocultural settings. At the same time, physiological adaptability and phenotypic plasticity allow organisms to respond to and limit stressors over their lifetimes.
Performance-Enhancing Drugs, Sport, and the Ideal of Natural Athletic Performance
Published in The American Journal of Bioethics, 2018
The human organism is characterized by strong adaptive capabilities and a high degree of phenotypic plasticity. Human beings can adjust to a diversity of ecological niches and develop specialized skills and technologies to cope with most environmental challenges and contexts.3 For a general view of the biology of human development and adaptive capacities, see Mayr (1997, 227–47). Enhancement of sport performance provides good examples. Phenotypic plasticity can be observed in physiological responses to environmental impact, for instance, in terms of increased hematocrit levels as adaptation to hypoxia (Schlichting and Wund 2014), and in athletes' active efforts to exploit adaptation potential as in training.
Cafeteria diet during lactation and/or post-lactation altered lipid profile/lipid peroxidation and increased anxiety-like behavior in male rat offspring
Published in Nutritional Neuroscience, 2020
Camyla Rocha de Carvalho Guedine, Liana Clébia de Morais Pordeus, Tania Regina Riul, Alceu Afonso Jordão, Sebastião Sousa Almeida
The habits of maternal life are capable of modulating the offspring’s phenotype, development, and behavior. More specifically, they are able to alter neural functions and cognitive and neuroendocrine aspects.1,2 Among these habits, the consumption of an inappropriate diet during gestation and lactation results in modifications in the mother’s and offspring’s organisms.3–5 This is mainly due to the maternal diet’s influence on the milk composition offered to the animals.4,5 This phenomenon, known as phenotypic plasticity, refers to the ability of an organism to react to an internal and external environment with changes in shape, state, physiology or activity rate without genetic modifications.6