Sex, Difference, and Desire

2020 ◽  
pp. 177-232
Author(s):  
Ben Bradley

The parts of The Descent of Man dealing with sexual desire and difference have sparked more controversy and misrepresentation than any of Darwin’s other publications. Crucial to Descent’s arguments is the derivation of sexual selection from the dramas of display and desire observed among animals. The book describes four plotlines structuring the theatre of sexual agency in animals, each having different implications for the roles played by males and females. When Descent extends these plotlines to humans, they alter and modulate into an even more varied array of scenarios, again, each with its own distinctive roles for women and men. A mirror-dynamic figures centrally in both animal and human sex—the need to recognize or predict others’ desires so as to act in a way to arouse them. However, several nodes of concern disturb Darwin’s presentation of human sex: tensions between his three epochs of human history; Victorian racial politics; Victorian ideas about male and female superiority; and the imperatives of propriety. The chapter illustrates some of the muddles that result from these concerns, including: confirmation bias; aporia in argument; grammatical kinks; and overlap between sexual and natural selection. Finally, the chapter instances some of the main resonances in more recent scholarship of Darwin’s discussion of sex, instancing debates in feminism, about anthropomorphism, in evolutionary biology, and evolutionary psychology.

1996 ◽  
Vol 19 (2) ◽  
pp. 254-255
Author(s):  
Michael T. Ghiselin

AbstractIn Darwinian terminology, “sexual selection” refers to purely reproductive competition and is conceptually distinct from natural selection as it affects reproduction generally. As natural selection may favor the evolution of sexual dimorphism by virtue of the division of labor between males and females, this possibility needs to be taken very seriously.


Author(s):  
Michael Ruse

Charles Robert Darwin, the English naturalist, published On the Origin of Species in 1859 and the follow-up work The Descent of Man in 1871. In these works, he argued for his theory of evolution through natural selection, applying it to all organisms, living and dead, including our own species, Homo sapiens. Although controversial from the start, Darwin’s thinking was deeply embedded in the culture of his day, that of a middle-class Englishman. Evolution as such was an immediate success in scientific circles, but although the mechanism of selection had supporters in the scientific community (especially among those working with fast-breeding organisms), its real success was in the popular domain. Natural selection, and particularly the side mechanism of sexual selection, were known to all and popular themes in fiction and elsewhere.


2018 ◽  
Author(s):  
Russell A. Ligon ◽  
Christopher D. Diaz ◽  
Janelle L. Morano ◽  
Jolyon Troscianko ◽  
Martin Stevens ◽  
...  

Ornaments used in courtship often vary wildly among species, reflecting the evolutionary interplay between mate preference functions and the constraints imposed by natural selection. Consequently, understanding the evolutionary dynamics responsible for ornament diversification has been a longstanding challenge in evolutionary biology. However, comparing radically different ornaments across species, as well as different classes of ornaments within species, is a profound challenge to understanding diversification of sexual signals. Using novel methods and a unique natural history dataset, we explore evolutionary patterns of ornament evolution in a group - the birds-of-paradise - exhibiting dramatic phenotypic diversification widely assumed to be driven by sexual selection. Rather than the tradeoff between ornament types originally envisioned by Darwin and Wallace, we found positive correlations among cross-modal (visual/acoustic) signals indicating functional integration of ornamental traits into a composite unit - the courtship phenotype. Furthermore, given the broad theoretical and empirical support for the idea that systemic robustness - functional overlap and interdependency - promotes evolutionary innovation, we posit that birds-of-paradise have radiated extensively through ornamental phenotype space as a consequence of the robustness in the courtship phenotype that we document at a phylogenetic scale. We suggest that the degree of robustness in courtship phenotypes among taxa can provide new insights into the relative influence of sexual and natural selection on phenotypic radiations.Author SummaryAnimals frequently vary widely in ornamentation, even among closely related species. Understanding the patterns that underlie this variation is a significant challenge, requiring comparisons among drastically different traits - like comparing apples to oranges. Here, we use novel analytical approaches to quantify variation in ornamental diversity and richness across the wildly divergent birds-of-paradise, a textbook example of how sexual selection can profoundly shape organismal phenotypes. We find that color and acoustic complexity, along with behavior and acoustic complexity, are positively correlated across evolutionary time-scales. Positive covariation among ornament classes suggests that selection is acting on correlated suites of traits - a composite courtship phenotype - and that this integration may be partially responsible for the extreme variation we see in birds-of-paradise.


Author(s):  
Jon D. Wisman

Whereas President Barack Obama identified inequality as “the defining challenge of our time,” this book claims more: it is the defining issue of all human history. The struggle over inequality has been the underlying force driving human history’s unfolding. Drawing on the dynamics of inequality, this book reinterprets history and society. Beyond according inequality the central role in human history, this book is novel in two other respects. First, transcending the general failure of social scientists and historians to anchor their work in explicit theories of human behavior, this book grounds the origins and dynamics of inequality in evolutionary psychology, or, more specifically, Darwin’s theory of sexual selection. Second, this book is novel in according central importance to the critical historical role of ideology in legitimating inequality, a role typically ignored or given little attention by social scientists and historians. Because of the central role of inequality in history, inequality’s explosion over the past 45 years has not been an anomaly. It is a return to the political dynamics by which elites have, since the rise of the state, taken practically everything for themselves, leaving all others with little more than the means with which to survive. Due to elites’ persuasive ideology, even after workers in advanced capitalist countries gained the franchise to become the overwhelming majority of voters, inequality continued to increase. The anomaly is that the only intentional politically driven decline in inequality occurred between the 1930s and 1970s following the Great Depression’s partial delegitimation (this should remain delegitimation globally) of elites’ ideology.


Author(s):  
Leigh W. Simmons

‘Sex roles and stereotypes’ examines the notion, implicit in many of the original ideas about sexual selection, that males and females have natural ‘roles’ with characteristic behaviour associated with each sex. It also explores further the reasons behind deviations from the ‘typical’ sex roles in mate choice and in mating competition. Are there ‘standard’ male and female roles in both humans and other animal species? One version of sex roles holds that males are generally dominant and females submissive, stemming from the way that sexual selection favours different behaviours in each sex. This could mean that sexual selection dictates particular behaviours in males and females. But in fact, sexual behaviour is extraordinarily varied in nature.


2021 ◽  
Vol 28 (5) ◽  
pp. 275-280
Author(s):  
Vadim V. Yartsev ◽  
Sophiya S. Evseeva ◽  
Irina V. Maslova ◽  
Darya A. Rogashevskaya

The cloaca of salamanders is a complex organ with exocrine glands involved in the production of sex pheromones, spermatophores, and storage of sperm. Since the cloaca provides reproductive functions, its signs are important for phylogenetic analysis in the evolutionary biology of tailed amphibians. For clarification of intrafamilial variation of cloacal characteristics in hynobiids, we studied the anatomy of male and female cloacae of Onychodactylus fischeri via histological, histochemical, and 3D-reconstruction methods. Males and females had ciliated cloacal linings and with sexual dimorphism in cloacal conformation and cloacal glands. As in other males and females of hynobiids, females of O. fischeri possessed only ventral glands, secreting neutral glycoproteins. In contrast, males of this species had three types of the cloacal glands. Glands «B» were like ventral glands of females and other hynobiids, while glands «A» and «C» had different histochemical and morphological characteristics. As our results are generally consistent with the data for the related species O. japonicus, these characteristics of the male and female cloacal anatomy may be common to all species of the genus Onychodactylus. The presence of three types of unique cloacal glands in males distinguishes Onychodactylus from all other hynobiids and salamanders.


2021 ◽  
pp. 481-510
Author(s):  
Graham Mitchell

The product of natural selection over at least 15 million years is the elongated, slender shape of giraffes that fits the natural habitat giraffes now occupy. What selection pressures operated to produce their shape? Their shape is partly the product of gravity and could have been an accidental by-product of selection for a large body mass and the protection from predation that large size brings, but the prevailing explanation is that their shape confers a browsing advantage. Preferred browse is concentrated at a height easily reached by giraffes but not by other browsers and natural selection would have favored those giraffes that could reach it. An alternative hypothesis is that their shape confers thermoregulatory benefits in addition to improved vigilance. Another hypothesis is that a long neck evolved to counter long legs allowing giraffes to drink surface water. An attractive hypothesis is that their shape is a product of ‘runaway’ sexual selection by females for males with long heavy necks, but analysis of this hypothesis has shown that the morphology of male and female giraffe does not differ. Nevertheless, all these possibilities could have contributed. A consequence of selection for their shape is over-specialization: giraffes seem to be inextricably dependent on a narrow diet, a diet that is subject to the vagaries of climate and competition for resources. The greatest threat to their survival is, therefore, their shape.


2015 ◽  
Vol 75 (2) ◽  
pp. 435-441 ◽  
Author(s):  
R. Maestri ◽  
R. Fornel ◽  
TRO. Freitas ◽  
JR. Marinho

Ontogenetic allometry is the study of how the size or shape of certain structures changes over the course of an animal’s development. In this study, using Huxley's formula of allometric growth (1932), we assessed the changes in the rate of growth of the feet size of the sigmodontine rodent Oligoryzomys flavescens during its ontogeny and compared differences between males and females. We find evidence of a change of polarity during the ontogenetic development of the species, with the presence of positive allometry during pregnancy and negative allometry in adulthood. Moreover, we note the presence of sexual dimorphism in the size of the feet, in which males of the species have a higher rate of growth than females. This growth pattern is positively related to escape from predators in childhood in both sexes and, in adulthood, provides a higher encounter rate of females by males, due to the larger displacement of the latter. We suggest that both the forces of natural selection and sexual selection have acted to shape the evolution of foot size in this species.


BJHS Themes ◽  
2021 ◽  
pp. 1-21
Author(s):  
Piers J. Hale

Abstract Although many read Charles Darwin's Origin of Species as an endorsement, rather than merely a description, of individualism and competition, in Descent of Man (1871) Darwin intended to show that natural selection could account for the most noble aspects of human morality and conscience. He did so in response to Alfred Russel Wallace's 1869 statement to the contrary. In doing so, Darwin appealed to the natural selection of groups rather than individuals, and to the maternal, parental and filial instincts, as the origin of truly other-regarding moral sentiments. Further, the inheritance of acquired characters and sexual selection had important implications for Darwin's understanding of how other-regarding ethics might prevail in an evolutionary framework that seemed to reward self-interest. In a short addendum to this essay I highlight just three of a number of Darwin's contemporaries who were impressed by this aspect of his work: the science popularizer Arabella Buckley, the Scottish Presbyterian scholar Henry Drummond and the anarchist geographer and naturalist Peter Kropotkin. In closing, I point to an extensive network of others who framed their concerns about both the ‘labour question’ and the ‘woman question’ in evolutionary terms, as a fruitful area for future research in this direction.


BJHS Themes ◽  
2021 ◽  
pp. 1-22
Author(s):  
Nasser Zakariya

Abstract Darwin in The Descent of Man deliberates over the question of progress in relation to three categories of traits – aesthetic, moral and intellectual – attending to their interplay. The later formulations of Thomas Henry Huxley and Alfred Russel Wallace shift and reframe the terms for weighing together progress and the relationship across these traits, downplaying the role of aesthetic assessments. Huxley and Wallace invoke ‘antagonisms’ countering, respectively, ‘ethical progress’ and ‘cosmic process’, ‘humanity – the essentially human emotion’ and ‘physical and even intellectual race-improvement’. Thereafter, evolutionary antagonisms reappear – whether to endorse, dismiss or overcome them – and they remain relevant in evolutionary arguments, whether made explicit or left implicit. Following a thread of ongoing appeals to this interplay of traits and corresponding antagonisms invoking Huxley's 1893 lecture ‘Evolution and ethics’, implicit differences appear in the treatment of aesthetic, moral and intellectual development. These treatments maintain the progress that their own ethical systems represented, even while granting moral variation and conceding independent/alternative notions of the beautiful. They generally took as granted the uniformity of intellectual judgements, where evolutionary progress was both ethical and intellectual/scientific, even when speculating on the development of different types of mind. As characteristic of future-oriented visions of progress by the first decades of the twentieth century, sexual selection was subsumed under natural selection.


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