Aesthetic modes and categories of perception and judgement were crucial to the development of Charles Darwin’s “theory of descent with modification through natural selection.” Indeed, Darwin understood the aesthetic as fundamentally constitutive of the natural historian’s method. In the closing retrospect of the journal of his circumnavigation as ship’s naturalist on HMS Beagle (1836), Darwin assesses his experience in aesthetic terms—of pleasure and pain, wonder and horror, the picturesque and sublime—rather than in terms of acquired scientific knowledge. Darwin’s account of the voyage makes aesthetic discrimination the main technique of natural-historical observation: it affords cognition of the natural world as a complex interplay of formal differences constituting a dynamic totality, a living system. A key aesthetic category, the sublime, articulates the awful discrepancy between human and natural scales of history, event, and meaning. Darwin makes a strategic appeal to the aesthetic to justify his new vision of nature to the Victorian public, overriding its scandalous ethical and political implications, in On the Origin of Species (1859): “There is grandeur in this view of life . . . from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” As well as the exposition of an argument, the Origin is a treatise on method. Darwin trains his readers to appreciate the evaluative scrutiny of formal difference that characterizes the operation of natural selection itself. The opening chapter, on artificial selection, proposes the domestic animal breeder as a “connoisseur,” expert in assessing minute morphological variations without concern for an ultimate end—that is, the improvement of the race. The figure is an analogue for natural selection, the motive principle of which is the fine but decisive discrimination (for life or death) of individual differences. The “powers of discrimination and taste” determine human evolution—constituting its medium, the semi-autonomous domain of culture—according to Darwin’s next synthetic statement of his theory. The Descent of Man (1871) proposes the supplementary agency of sexual selection as the main motor of human cultural development. Its productive principle is, once again, the evaluation of fine formal differences (“there is in the mind of man a strong love for slight changes in all things”), trained, however, upon pleasurable appearance rather than function or use. Sexual selection generates “the differences in external appearance between the races of man,” as well as between the sexes, explicitly on grounds of aesthetic preference: Darwin conflates skin color, body hair, and other physiological features with artificial ornaments in a rhapsodic vision of the infinite variety of human standards of beauty. Sexual selection claims a field of formal superfluity or redundancy, neutral with respect to the pressures of natural selection, in which the aesthetic comes into play, originated by the erotic drive but not functionally bound by it. Darwin decisively relocates aesthetic judgement—and the play of form—upon a principle of etiologically generated, infinite formal differentiation: emancipating it from the strongly normative teleological account that Victorian culture took over from German Idealism.
Richard Ned Lebow
Evolution, as a biological process and a metaphor, has utility in our understanding of international relations. The former is largely inapplicable for obvious, conceptual, and empirical reasons; but the latter is more promising, though those who use it must be explicit about its limitations. There must be considerations on how evolution contrasts with conscious adaption and imitation, on the argument for the need to distinguish among them analytically and empirically, and on the further exploration of the different conditions in which these other two mechanisms might be relevant.
Juha Merilä and Ary A. Hoffmann
Changing climatic conditions have both direct and indirect influences on abiotic and biotic processes and represent a potent source of novel selection pressures for adaptive evolution. In addition, climate change can impact evolution by altering patterns of hybridization, changing population size, and altering patterns of gene flow in landscapes. Given that scientific evidence for rapid evolutionary adaptation to spatial variation in abiotic and biotic environmental conditions—analogous to that seen in changes brought by climate change—is ubiquitous, ongoing climate change is expected to have large and widespread evolutionary impacts on wild populations. However, phenotypic plasticity, migration, and various kinds of genetic and ecological constraints can preclude organisms from evolving much in response to climate change, and generalizations about the rate and magnitude of expected responses are difficult to make for a number of reasons. First, the study of microevolutionary responses to climate change is a young field of investigation. While interest in evolutionary impacts of climate change goes back to early macroevolutionary (paleontological) studies focused on prehistoric climate changes, microevolutionary studies started only in the late 1980s. The discipline gained real momentum in the 2000s after the concept of climate change became of interest to the general public and funding organizations. As such, no general conclusions have yet emerged. Second, the complexity of biotic changes triggered by novel climatic conditions renders predictions about patterns and strength of natural selection difficult. Third, predictions are complicated also because the expression of genetic variability in traits of ecological importance varies with environmental conditions, affecting expected responses to climate-mediated selection. There are now several examples where organisms have evolved in response to selection pressures associated with climate change, including changes in the timing of life history events and in the ability to tolerate abiotic and biotic stresses arising from climate change. However, there are also many examples where expected selection responses have not been detected. This may be partly explainable by methodological difficulties involved with detecting genetic changes, but also by various processes constraining evolution. There are concerns that the rates of environmental changes are too fast to allow many, especially large and long-lived, organisms to maintain adaptedness. Theoretical studies suggest that maximal sustainable rates of evolutionary change are on the order of 0.1 haldanes (i.e., phenotypic standard deviations per generation) or less, whereas the rates expected under current climate change projections will often require faster adaptation. Hence, widespread maladaptation and extinctions are expected. These concerns are compounded by the expectation that the amount of genetic variation harbored by populations and available for selection will be reduced by habitat destruction and fragmentation caused by human activities, although in some cases this may be countered by hybridization. Rates of adaptation will also depend on patterns of gene flow and the steepness of climatic gradients. Theoretical studies also suggest that phenotypic plasticity (i.e., nongenetic phenotypic changes) can affect evolutionary genetic changes, but relevant empirical evidence is still scarce. While all of these factors point to a high level of uncertainty around evolutionary changes, it is nevertheless important to consider evolutionary resilience in enhancing the ability of organisms to adapt to climate change.
Intergroup communication concerns the verbal and nonverbal interaction between individuals from different groups. Since about the 1980s, the social identity perspective (including social identity, self-categorization, ethnolinguistic vitality, and communication accommodation theories) has provided much impetus to research on intergroup communication. One way to advance intergroup communication research, then, is to expand the social identity perspective. Evolutionary psychology, a research program firmly rooted in natural selection theory and its modern synthesis, can help achieve this goal. For example, a functional analysis of language acquisition suggests—and research confirms—that language (similar to sex and age but not race) is a dedicated dimension of social categorization. This is first of all because language is localized, with signal regularities (e.g., grammar, syntax) being meaningful only to in-group members. Second, there is a critical window of language acquisition that typically closes at late adolescence, and one can almost never reach native-level proficiency if the person tries to learn a language beyond that window. Thus, two people are very likely to have grown up in the same place if they speak the same language with similar high levels of proficiency. Conversely, the lack of proficiency in speaking a language suggests that one does not have the same childhood experience as others and is thus an out-group member. Because ancestral humans had recurrent exposure to people speaking different languages (or variants of the same language) even given their limited travel ability, language-based categorization appears to be an evolved part of human nature. Evolutionary theories can also help renovate research on ethnolinguistic vitality and (non)accommodation. For example, an analysis of host-parasite coevolution suggests that maintaining and using one’s own language can help reduce the risk of contracting foreign diseases in places with high parasite stress. This is because out-group members are more likely than in-group members to carry diseases that one’s physiological immune system cannot tackle. Intergroup differentiation is thus needed more in places with higher parasite stress, and language (as noted) reliably marks group membership. It thus benefits people living in parasite-laden environments to stick to their own language, which helps them remain close to in-group members and away from out-group members. Research also shows that increases in perceived parasitic threats cause people higher in pathogen disgust sensitivity to perceive speakers with foreign accents as being more dissimilar to self. This enhanced perceived dissimilarity may cause non-accommodation or divergence in intergroup communication, resulting in negative language attitudes and even intergroup conflicts. These and many other areas of research uniquely identified by evolutionary approaches to intergroup communication research await further empirical tests.
Conscience P. Bwiza, Jyung Mean Son, and Changhan Lee
Aging is a progressive process with multiple biological processes collectively deteriorating with time, ultimately causing loss of physiological functions necessary for survival and reproduction. It is also thought to have a strong evolutionary basis, largely resulting from the lack of selection force. Here, we discuss the evolutionary aspects of aging and a selection of theories founded on a variety of biological functions that have been shown to be involved in aging in multiple model organisms, ranging from the simple yeast, worms, flies, killifish, and rodents, to non-human primates and humans. The conglomerate of distinct theories has together revolutionized aging research in the past several decades, far more than what humankind has known since the dawn of civilization. However, not one theory alone can independently explain aging and should not be interpreted out of context of the cell and organism in its entirety. That said, the 21st century has been and will be an exciting time in the field of aging, with scientific advances on health span and lifespan being made at multiple fronts of biology and medicine in an unprecedented scale.