The Descent of Man, and Selection in Relation to Sex

The Descent of Man, and Selection in Relation to Sex is a foundational work by the English naturalist Charles Darwin, published in 1871. Building upon the theory of natural selection introduced in his earlier work, On the Origin of Species, this two-volume treatise applied evolutionary principles directly to humanity. It argued for the common ancestry of humans and other animals, and introduced the concept of sexual selection as a major evolutionary force. The book generated intense debate in Victorian society and profoundly influenced fields from anthropology to psychology.

Background and publication

Following the 1859 publication of On the Origin of Species, Charles Darwin deliberately avoided extensive discussion of human evolution, noting only that "light will be thrown on the origin of man and his history." However, by the late 1860s, spurred by the work of colleagues like Alfred Russel Wallace and Thomas Henry Huxley, and the growing acceptance of evolutionary theory, Darwin began compiling evidence. He corresponded extensively with experts such as the botanist Joseph Dalton Hooker and the embryologist Ernst Haeckel. The book was published on 24 February 1871 by his long-time publisher, John Murray, in London. The first edition sold out quickly, reflecting enormous public interest and the notoriety of its author following the controversy over *Origin*.

Summary of contents

Volume One focuses on evidence for human evolution from comparative anatomy, embryology, and rudimentary organs, arguing that humans share a common ancestor with other primates. Darwin drew on observations from global explorations, including those from the voyage of the *Beagle*, and cited studies of gorillas and orangutans. Volume Two is almost entirely devoted to the theory of sexual selection, which Darwin proposed to explain traits not easily accounted for by survival alone. He detailed mechanisms like male-male competition and female choice, illustrating them with exhaustive examples from the animal kingdom, including the plumage of birds-of-paradise, the antlers of red deer, and the songs of insects. The work concludes with discussions on the role of sexual selection in human racial differences and the development of moral faculties.

Primary arguments and themes

The central argument is that humans evolved from ancestral forms through the same processes of natural selection and sexual selection observed in other species. Darwin challenged the special creation of humanity, placing humans firmly within the natural world. A major thematic innovation was the detailed exposition of sexual selection, positing it as a powerful secondary evolutionary driver responsible for many ornamental and behavioral traits. He also explored the evolution of mental faculties, morality, and social instincts, suggesting they arose through the advantages they conferred to tribal groups, a concept later foundational to evolutionary psychology. The book engaged with contemporary debates on topics like the Great Chain of Being and the monogenism versus polygenism of human races.

Reception and contemporary criticism

Initial reception was polarized, with many in the scientific community, such as Alfred Russel Wallace and St. George Jackson Mivart, offering significant critiques, particularly regarding the application of sexual selection to humans. Religious figures, including Samuel Wilberforce, condemned its implications for human dignity and biblical authority, reigniting tensions from the 1860 Oxford evolution debate. However, it was praised by supporters like Ernst Haeckel and Thomas Henry Huxley, who saw it as a logical extension of evolutionary theory. Popular press in publications like The Times and The Spectator widely discussed its provocative conclusions, ensuring its place at the center of public discourse on science and religion.

Scientific legacy and modern assessment

The work established sexual selection as a major pillar of evolutionary biology, a field later advanced by scientists like Ronald Fisher and Amotz Zahavi. Its ideas directly influenced the development of ethology, pioneered by Konrad Lorenz and Niko Tinbergen. While some of its Victorian-era anthropological assumptions about race and gender are now considered outdated, its core evolutionary framework remains valid. Modern research in genetics, such as the Human Genome Project, has confirmed the close genetic relationship between humans and other primates that Darwin argued for. The book is recognized as a courageous and pivotal step in applying evolutionary theory to all aspects of human existence, shaping disciplines from biological anthropology to sociobiology.

Category:1871 non-fiction books Category:Books by Charles Darwin Category:Evolutionary biology literature