NationMaster - Encyclopedia: Descent of Man

The Descent of Man and Selection in Relation to Sex by The word Britain is used to refer to the United Kingdom (UK) the island of Great Britain, which consists of the countries of England, Scotland, and Wales sometimes the Roman province called Britain or Britannia The word British generally means belonging to or associated with Britain in either of the...British Natural history is an umbrella term for what are now usually viewed as a number of distinct scientific disciplines. ...naturalist For other possible meanings see Darwin (disambiguation) Charles Darwin, about the same time as the publication of The Origin of Species. ...Charles Darwin was first published in 1871 was a common year starting on Sunday (see link for calendar). ...1871. It was Darwin's second large book on evolutionary theory, following his 1859 is a common year starting on Saturday. ...1859 work, The 1859 edition of On the Origin of Species First published in 1859, The Origin of Species (full title On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) by British naturalist Charles Darwin is one of the pivotal...The Origin of Species, and is concerned with outlining explicitly the application of Darwin's theory to Human evolution is a multidisciplinary scientific inquiry which seeks to understand and describe the origin and development of humanity. ...human evolution, and outlining in detail the theory of Illustration from The Descent of Man and Selection in Relation to Sex by Charles Darwin showing the tufted coquette Lophornis ornatus, female on left, ornamented male on right. ...sexual selection.

Darwin's background issues and concerns

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Charles Darwin's second book of theory involved many questions of Darwin's time.

Charles Darwin's Origin of Species had been met with a firestorm of controversy, largely because it was clear that it implied that human beings were evolved from animals, contradicting the story of This article is about Genesis, the first book of the Hebrew Bible. ...Genesis and implying an animal nature. Darwin had not made the link explicit in Origin, though; a single line hinted at such a conclusion: "light will be thrown on the origin of man and his history". But the conclusion was fairly obvious to his contemporaries, and became the subtext if not the center of many debates over his theory (such as those between Thomas Huxley Thomas Henry Huxley F.R.S. (May 4, 1825 _ June 29, 1895) was a British biologist, known as Darwins Bulldog for his defence of Charles Darwins theory of evolution. ...T.H. Huxley and Sir Richard Owen and Dinornis bird skeleton Sir Richard Owen (July 20, 1804 _ December 18, 1892) was an English biologist, comparative anatomist and palaeontologist. ...Richard Owen over the brains of apes).

Darwin's writing on the subject in The Descent of Man came twelve years after his work on Origin, and was by far not the first work on human evolution. As such, the book is a response to various debates of Darwin's time far more wide_ranging than the questions he raised in Origin. It is often erroneously assumed that the book was controversial because it was the first to outline the idea of human evolution and A group of organisms is said to have common descent if they have a common ancestor. ...common descent. Coming out so late into that particular debate, while it was clearly Darwin's intent to weigh in on this question, his goal was to approach it through a specific theoretical lens (sexual selection) which had previously been undiscussed by the other commentators at the period.

Human faculties

The major sticking point for many in the question of human evolution was whether or not human mental faculties could have possibly been evolved. The gap between humans and even the smartest ape seemed too large even for those who were sympathetic to Darwin's larger theory. Alfred Russel Wallace Alfred Russel Wallace (January 8, 1823 — November 7, 1913) was a British naturalist, geographer, anthropologist and biologist. ...Alfred Russel Wallace, the "co_discoverer" of evolution by Alternative meaning Natural Selection (computer game). ...natural selection, believed that the human mind was too complex to have evolved gradually, and began over time to subscribe to a theory of evolution which took more from Spiritualism is a religion in which contact with the spirits of the dead through a medium is central. ...spiritualism than it did the natural world. Darwin was deeply distressed by Wallace's change of heart and much of the Descent of Man is in response to opinions put forth by Wallace. Darwin focuses less on the question of whether humans evolved as it does on displaying that each of the human faculties considered to be so far beyond those of animals—such as moral reasoning, sympathy for others, beauty, and music—can be seen in kind (if not degree) in other animal species (usually apes and dogs).

Human races

The questions of what " This article is about race as an intraspecies classification. ...race" was, how many human races there were, and whether they could be "mixed", were key debates in the nascent field of Anthropology (from the Greek word άνθρωπος = human) consists of the study of humankind (see genus Homo). ...anthropology in Darwin's time. After the The American Civil War was fought in the United States from 1861 until 1865 between the United States – forces coming mostly from the 23 northern states of the Union – and the newly_formed Confederate States of America, which consisted of 11 southern states that had declared their secession. ...American Civil War ( 1861 is a common year starting on Tuesday. ...1861_ 1865 is a common year starting on Sunday. ...1865), the question of race and slavery were brought to the forefront in anthropology in the United States and Europe. Many scientists from the Southern U.S. were publishing long monographs on why the " Negro means the color black in both Spanish and Portuguese languages, being derived from the Latin word niger of the same meaning. ...Negro" was inferior and would soon be driven to extinction by newfound freedom, with an implication that slavery had been not only "beneficial" but "natural". Darwin was a long_time abolitionist who had been horrified by Slavery is any of a number of related conditions involving control of a person against his or her will, enforced by violence or other clear forms of coercion. ...slavery when he first came into contact with it in The Federative Republic of Brazil (República Federativa do Brasil in Portuguese) is the largest and most populous country in South America, and fifth largest in the world. ...Brazil while touring the world on the For other RN ships of this name, see HMS Beagle (disambiguation). ...HMS Beagle many years before, and considered the "race question" one of the most important of his day. Darwin took a radical view for his time—that all human beings were of the same In biology, a species is a kind of organism. ...species, and that races, if they were useful markers at all, were simple "sub_species" or "variants." This view (known as "monogenism") was in stark contrast with the majority view in anthropology at the time, that the different human races were distinct species ("polygenism"). Polygeny was supported by thinkers of many backgrounds, such as the Creationism is generally the belief that the universe was created by a deity, or alternatively by one or more powerful and intelligent beings. ...Creationist Louis Agassiz Jean Louis Rodolphe Agassiz (May 28, 1807_December 14, 1873) was a Swiss_American zoologist and geologist, the husband of educator Elizabeth Cabot Cary Agassiz, and one of the first world_class American scientists. ...Louis Agassiz, and by later thinkers who would interpret Darwin's theory to imply that races had been evolved at different times or stages. Darwin's own views of this were that the differences between human races were superficial (he discusses them only in terms of skin color and hair style), and much of Descent is devoted to the question of the human races. Aside from the aforementioned encounter with slavery on the Beagle, Darwin also was perplexed by the "savage races" he saw in South America at Tierra del Fuego (Spanish: land of fire) is an archipelago at the southernmost tip of South America. ...Tierra del Fuego, which he saw as evidence of a man's more primitive state of civilization. During his years in London, his private notebooks were riddled with speculations and thoughts on the nature of the human races, many decades before he would publish Origin.

Social implications of Darwinism

Darwin's cousin, Francis Galton Sir Francis Galton FRS (February 16, 1822 - January 17, 1911) was an English explorer, statistician, anthropologist, creator of modern eugenics (he coined the term), and investigator of the human mind. ...Francis Galton, proposed that an interpretation of Darwin's theory was the need for The word eugenics (from the Greek εὐγενής, for well-born) was coined in 1883 by Sir Francis Galton, a cousin of Charles Darwin, to refer to the study and use of selective breeding (of animals or humans) to improve a species over generations, specifically in regards to hereditary features. ...eugenics to save society from "inferior" minds.

Since the publication of Origin, a wide variety of opinions had been put forward on whether or not the theory had implications towards human society. One of these was what would later be known as Social Darwinism is a descriptive term given to a kind of social theory that draws an association between Darwins theory of evolution by natural selection, and the sociological relations of humanity. ...Social Darwinism, usually ascribed to the ideas of Herbert Spencer. ...Herbert Spencer, which argued that society would naturally separate itself along lines of the "more fit" and "less fit". Another of these interpretations, later known as The word eugenics (from the Greek εὐγενής, for well-born) was coined in 1883 by Sir Francis Galton, a cousin of Charles Darwin, to refer to the study and use of selective breeding (of animals or humans) to improve a species over generations, specifically in regards to hereditary features. ...eugenics, was put forth by Darwin's cousin, Francis Galton Sir Francis Galton FRS (February 16, 1822 - January 17, 1911) was an English explorer, statistician, anthropologist, creator of modern eugenics (he coined the term), and investigator of the human mind. ...Francis Galton, in 1865 is a common year starting on Sunday. ...1865 and 1869 is a common year starting on Friday (link will take you to calendar). ...1869. Galton argued that just as physical traits were clearly inherited among generations of people, so could be said for mental qualities (genius and talent). If this were true, Galton argued, then humans should arrange society in ways which would encourage the smartest members of society to reproduce more and discourage the "less fit" members of society not to reproduce. In Galton's view, social institutions such as Welfare has four main meanings. ...welfare and A psychiatric hospital (also called a mental hospital or asylum) is a hospital specializing in the treatment of persons with mental illness. ...insane asylums were allowing "inferior" humans to survive and reproduce at levels faster than the more "superior" humans in respectable society, and if corrections were not soon taken, society would be awash with "inferiors." Darwin read his cousin's work with interest, and devoted sections of Descent of Man to discussion of Galton's theories. Neither Galton nor Darwin, though, advocated any eugenic policies such as those which would be undertaken in the early 20th century, as government coercion of any form was very much against their political opinions.

Apparently non-adaptive features

In Darwin's view, anything that could be expected to have some adaptive feature could be explained easily with his theory of natural selection. In Origin, Darwin had admitted that to use natural selection to explain something as complicated as a human eye, "with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration" might at first appear "absurd in the highest possible degree," but nevertheless, if "numerous gradations from a perfect and complex eye to one very imperfect and simple, each grade being useful to its possessor, can be shown to exist", then it seemed quite possible to account for within his theory.

Peacock detail at Paignton Zoo, Devon, England. ...

"The sight of a feather in a Peacock re-directs here; for alternate uses see Peacock (disambiguation). ...peacock's tail, whenever I gaze at it, makes me sick!"

More difficult for Darwin were highly evolved and complicated features which conveyed apparently no adaptive advantage to the organism in question. He once wrote to a colleague that "The sight of a feather in a Peacock re_directs here; for alternate uses see Peacock (disambiguation). ...peacock's tail, whenever I gaze at it, makes me sick!" Why should a bird like the peacock develop such an elaborate tail, which seemed to at best be a hinderance in its "struggle for existence"? To answer the question, Darwin developed the theory of Illustration from The Descent of Man and Selection in Relation to Sex by Charles Darwin showing the tufted coquette Lophornis ornatus, female on left, ornamented male on right. ...sexual selection, which outlined how different characters could be selected for if they conveyed a reproductive advantage to the individual. In Darwin's version of the theory, male animals in particular received the benefits of sexual selection, either by acquiring "weapons" with which to fight over females with other males, or by acquiring beautiful plumage with which to woo the female animals. Much of Descent is devoted to providing evidence for sexual selection in nature, which he also ties in to the development of aesthetic instincts in human beings, as well as the differences in coloration between the human races.

Darwin had developed his ideas about sexual selection for this reason since at least the 1850s, and had originally intended to include a long section on the theory in his large, unpublished book on species. When it came to writing Origin, though (his "abstract" of the larger book), he did not feel he had sufficient space to engage in sexual selection to any strong degree, and included only three paragraphs devoted to the subject. Darwin considered sexual selection to be as much of a theoretical contribution of his as was his natural selection, and the vast majority of Descent is devoted exclusively to this topic.

Part I: The evolution of man

Evolution of physical traits

Darwin's approach to arguing for the evolution of human beings is to outline how similar human beings are to other animals. He begins by using Anatomical drawing of the human muscles from the Encyclopédie. ...anatomical similarities, focusing on body structure, Developmental biology or embryology (Greek εμβρυολογία) is the study of the process by which organisms grow and develop. ...embryology, and "rudimentary organs" which are presumably useful in one of man's "pre_existing" forms. He then moves on to arguing for the similarity of mental characteristics.

Evolution of mental traits

Based on the work of his cousin Galton, Darwin is able to assert that human character traits and mental characteristics are inherited the same as physical characteristics, and argues against the mind/body distinction for the purposes of evolutionary theory. From this Darwin then provides evidence for similar mental powers and characteristics in certain animals, focusing especially on apes, monkeys, and dogs for his analogies for love, cleverness, religion, kindmess, and altruism. He concludes on this point that "Nevertheless the difference in mind between man and the higher animals, great as it is, certainly is one of degree and not of kind." He additionally turns to the behavior of "savages" to show how many aspects of Victorian England's society can be seen in more primitive forms.

In particular, Darwin argues that even moral and social instincts are evolved, comparing religion in man to fetishism in "savages" and his dog's inability to tell whether a wind_blown parasol was alive or not. Darwin also argues that all civilizations had risen out of barbarism, and that he did not think that barbarism is not a "fall from grace" as many commentators of his time had asserted.

Natural selection and civilized society

In this section of the book, Darwin also turns to the questions of what would after his death be known as Social Darwinism is a descriptive term given to a kind of social theory that draws an association between Darwins theory of evolution by natural selection, and the sociological relations of humanity. ...social Darwinism and The word eugenics (from the Greek εὐγενής, for well_born) was coined in 1883 by Sir Francis Galton, a cousin of Charles Darwin, to refer to the study and use of selective breeding (of animals or humans) to improve a species over generations, specifically in regards to hereditary features. ...eugenics. Darwin notes that, as had been discussed by Alfred Russel Wallace Alfred Russel Wallace (January 8, 1823 — November 7, 1913) was a British naturalist, geographer, anthropologist and biologist. ...Alfred Russel Wallace and Galton, natural selection seemed to no longer act upon civilized communities in the way it did upon other animals:

But Darwin felt that these urges towards helping the "weak members" was part of our evolved instinct of sympathy, and concluded that "nor could we check our sympathy, even at the urging of hard reason, without deterioration in the noblest part of our nature." As such, '"we must therefore bear the undoubtedly bad effects of the weak surviving and propagating their kind." Darwin was sympathetic to the views of the Social Darwinists and the eugenicists, but he did not believe that action should be taken. He did feel, though, that the "savage races" of man would be subverted by the "civilised races" at some point in the near future: "At some future period, not very distant as measured by centuries, the civilised races of man will almost certainly exterminate, and replace, the savage races throughout the world." Darwin is not advocating Genocide has been defined as the deliberate killing of people based on their ethnicity, nationality, race, religion, or (sometimes) politics, as well as other deliberate actions leading to the physical elimination of any of the above categories. ...genocide, but clinically predicting, by analogy to the ways in which "more fit" varieties within a species would displace other varieties, the likelihood that indigenous peoples will eventually die out from their contact with "civilization", or become absorbed into it completely.

His political opinions (and Galton's as well) were strongly inclined against the coercive, authoritarian forms of eugenics which later became so prominent in the twentieth century. It is worth noting that even Galton's ideas about eugenics were not the Compulsory sterilization programs sprouted up in many countries at the beginning of the 20th century, usually as part of a program of negative eugenics __ to prevent undesirable members of the population from reproducing. ...compulsory sterilization or genocidal programs of Nazi Germany, or the Third Reich, commonly refers to Germany in the years 1933–1945, when it was under the firm control of the totalitarian and fascist ideology of the Nazi Party, with the Führer Adolf Hitler as dictator. ...Nazi Germany, but he instead hoped that by encouraging more thought in hereditary reproduction, human mores could change in a way which would compel people to choose better mates.

The race debate

Darwin lastly applied his theory to one of the more controversial scientific questions of his day: whether the different races of human beings were of the same species or not:

Darwin reasoned that most of the visual differences between human races were superficial—issues of skin color and hair type—and that most of the mental differences were merely cases of "civilization" or a lack of it. It was important to Darwin to argue that all races were of the same species—he had spent much of the preceeding book tracing humans back to the paleolithic age, and now he had to bring them back to the present time again. If the "savages" like those he met while on his Beagle voyage were not of the same species as civilized Englishmen, he would not be able to draw the complete continuum he felt necessary. Darwin concluded that the visual differences between races were not adaptive to any significant degree, and were more likely simply caused by sexual selection—different standards of beauty and mating amongst different people—and that all of humankind was one single species.

He concludes that "when the principle of evolution is generally accepted, as it surely will be before long, the dispute between the monogenists and the polygenists will die a silent and unobserved death." In one sense he was correct: few people, outside of the anthropologists of the American South, would maintain that different races were actually distinct species of animals for very much longer—the mounting evidence of their ability to interbreed and have fertile young was becoming unignorable, among other things. However, many found it easy to take a similar view to the old polygenism: that the races were indeed one species, but had diverged so long ago that significant differences between the races still existed. The evolutionary point fell out of debate, but the social point has continued (both inside and outside scientific circles) to the present day.

Part II and III: Sexual selection

Conclusion

Later debates

Darwin's views on sexual selection were opposed strongly by his "co_discoverer" of natural selection, Alfred Russel Wallace Alfred Russel Wallace (January 8, 1823 — November 7, 1913) was a British naturalist, geographer, anthropologist and biologist. ...Alfred Russel Wallace, though much of his "debate" with Darwin took place after Darwin's death. Wallace argued against sexual selection, saying that the aspects of it which were male_against_male fighting were simply forms of natural selection, and that the notion of "female choice" was attributing discerning standards of beauty to animals far too cognitively undeveloped to be feasible (such as Suborders Adephaga Archostemata Myxophaga Polyphaga many subgroups: see Subgroups of the order Coleoptera Beetles (order Coleoptera) are one of the main groups of insects. ...beetles). It should perhaps be noted that Wallace had previously had his own problem with "female choice": he had been left at the alter by a woman of a higher social class.

Wallace also argued that Darwin too much favored the bright colors of the male peacock as adaptive without realizing that the "drab" Peacock re_directs here; for alternate uses see Peacock (disambiguation). ...peahen's coloration is itself adaptive, as camoflage. Wallace more speculatively argued that the bright colors and long tails of the peacock were not adaptive in any way, and that bright coloration could result from non-adaptive physiological development (for example, the internal organs of animals, not being subject to a visual form of natural selection, come in a wide variety of bright colors). This has been questioned by later scholars as quite a stretch for Wallace, who in this particular instance abandoned his normally strict "adaptationist" agenda in asserting that the highly intricate and developed forms such as a peacock's tail resulted by sheer "physiological processes" that were somehow not at all subjected to adaptation.

Editions and reprints

Descent went through a large number of revised editions, many of which were edited by Darwin himself (and some were edited by his children). Some edits were minor, though some were extensive. The book was initially published in two separate volumes, though Darwin himself insisted that it was indeed one complete and coherent work.

Darwin's background issues and concerns

Human faculties

Human races

Social implications of Darwinism

Apparently non-adaptive features

Part I: The evolution of man

Evolution of physical traits

Evolution of mental traits

Natural selection and civilized society

The race debate

Part II and III: Sexual selection

Conclusion

Later debates

Editions and reprints

References

External links

Darwin's background issues and concerns GA_googleFillSlot("encyclopedia_square");

Human faculties

Human races

Social implications of Darwinism

Apparently non-adaptive features

Part I: The evolution of man

Evolution of physical traits

Evolution of mental traits

Natural selection and civilized society

The race debate

Part II and III: Sexual selection

Conclusion

Later debates

Editions and reprints

References

External links

Darwin's background issues and concerns