This results primarily as a consequence of polyandrous mating systems, or due to extra. But until human sperm competition there had never been a discussion of the phenomenon for the human species in book form, despite its relevance for a full understanding of human reproduction. The proper scientific documentation really is there. My husband wants to watch me with another man and im thinking about it. There is a very simple primal answer to why your husband enjoys this so.
Written 20 years ago in 199394, the print edition was published in 1995. Human sperm remain viable within the womans tract for up to seven days, not merely one or two days as scientists previously believed. Sperm competition occurs between sperm from two or more rival males when they make an attempt to fertilize a female within a sufficiently short period of time. Similar spermcontrol mechanisms have been uncovered previously. In this chapter, we present the evidence of sperm competition in humans. However, as a guy interested in both the practical application of science and the science itself, i would have liked an inbetween version. Sperm wars is a primarily nonfiction book by evolutionary biologist robin baker. Levels of human sperm competition, male adjustment of ejaculates, function of the female orgasm, penis shape, variation in testes size, female behavior through the menstrual cycle, and sperm. This is a textbook and i read it to win an argument, but my opponent refused to acknowledge my victory.
Psychological and physiological adaptations to sperm. In species where females mate with multiple males, the sperm from these males must compete to fertilise available ova. Sperm competition theory argues that the number of sperm inseminated into a female by a male is a tradeoff between two opposing pressures. Many scholars have focused on the occurrence of sperm competition which occurs when the sperm from two or more males occupy a womans reproductive tract. It was the first broad overview and recognition that sperm competition and promiscuity were ubiquitous. Despite its age that books contents are as relevant now as they were two decades ago.
Human homo sapiens facial attractiveness and sexual selection. In species where females mate with multiple males, the sperm of two or more males must compete to fertilise available ova. The risk of sperm competition has been argued to shape the evolution of almost every aspect of human sexuality. Selection from sperm competition is expected to favor opposing adaptations that function either in the avoidance of or engagement in sperm competition. Semen displacement as a sperm competition strategy in. Before the church and modern morals females were free to mate with as many males as they cared to. Copulation, masturbation and infidelity which is the academic text of their groundbreaking research. The human penis may have been selected to displace seminal fluids implanted in the female reproductive tract by a rival male. On the one hand, the risk that sperm may find themselves in competition with the sperm from another male favours the male inseminating more sperm. A third line of evidence comes from new research on human sperm competition. My husband wants to watch me with another man and im. Smiths own chapter on human sperm competition was exciting, stimulating and controversial. This volume brings together, in one place, a key set of classic and contemporary papers that have examined possible adaptations to sperm competition in humans. Keywords sperm competition, humans, comparative psychology, evolutionary psychology, comparative evolutionary psychology.
Dec 02, 2012 sperm competition and the evolution of animal mating systems describes the role of sperm competition in selection on a range of attributes from gamete morphology to species mating systems. This digital edition of the original 1995 publication, but at a studentfriendly price, now solves this problem. This book is organized into 19 chapters and begins with the conceptualization of sperm competition as a subset of sexual selection and its implications for the insects. If so, homosexual behaviour joins the ranks of a number of other human characteristics that are advantageous. Sperm competition and the evolution of animal mating systems describes the role of sperm competition in selection on a range of attributes from gamete morphology to species mating systems.
The best books on sperm five books expert recommendations. Writing books about the ethics ofgenetics genethics, to use the title of more than one such book has become a cottage industry. Human sperm competition copulation, masturbation and infidelity. Feb 22, 2000 sperm competition is possible in homo sapiens, though whether it has played a significant role during human evolution remains highly debatable, dr. Human sperm competition sets out the thesis that adopting an evolutionary approach to human reproduction exposes the subtle and sophisticated ways in which human. Sperm competition is a form of postcopulatory sexual selection whereby male ejaculates simultaneously physically compete to fertilize a single ovum. One evolutionary response to sperm competition is the variety in penis morphology of many species. You will see that sperm competition is further proof, that humans are polygamists. Behavioural ecologists and evolutionary biologists have for a numb. Human sperm competition by robin baker overdrive rakuten.
Sexual selection from sperm competition is expected to favor opposing adaptations in males that function either in the avoidance of sperm competition by guarding females from rival males or in the engagement in sperm competition by increased expenditure on the ejaculate. The book is a pioneering analysis of the evolutionary biology of human sexuality, proposing that all aspects have been shaped by the phenomenon of sperm. Sperm competition occurs when the sperm from two different men inhabit a womans reproductive tract at the same time. During periods of infidelity, however, females changed their orgasm pattern. Bob brought together everyone in the field and got them to write essays on key topics. Research shows that mixedgender porn stimulates sperm to swim faster than allwomen porn. These adaptations include traits that produce prudent sperm allocation, copulatory interest, forced inpair copulation. Behavioural ecologists and evolutionary biologists have long been interested in the biological implications of sperm from different males competing for fertilization of the egg in the female tract. Over the past decade, there has been a vast amount of interest in the subject of human sperm competition. Classic and contemporary readings 9780387280363 and a great selection of similar new, used and collectible books available now at. No evidence for killer sperm or other selective interactions between human spermatozoa in ejaculates of different males in vitro 1999. Copulation, masturbation, and infidelity springerlink. Porn helps human sperm gear up for competition popular. Since the 1970s, behavioural ecologists and evolutionary biologists have been fascinated by the biological implications of sperm from different males competing for fertilization of the egg in the female reproductive tract.
If you really want the solid data to convince you that virtually everything you want to believe is wrong, you should get a copy of human sperm competition. Until that point, we were rather reserved about these. Males have adapted to battle with competing sperm sciencedaily. This book is organized into 19 chapters and begins with the conceptualization of sperm competition as a subset of sexual selection and its implications for. It was good for the species, whether the females mate liked it or not. The relationship between objective sperm competition risk and mens copulatory interest is moderated by partners time spent with other men. The changes would have been cryptic to the male partners and would numerically have favoured the sperm from the extrapair male, presumably raising his chances of success in sperm competition with the females partner. The book focuses heavily on infidelity and explains the biological basis of sexual behavior. This book discusses these implications for human sexual behaviour and human infertility problems. Pdf sperm competition occurs when a female copulates with two or. Many scholars have focused on the occurrence of sperm competition which occurs when the sperm from two or more males occupy a womans reproductive tract at the same time, and hence compete to. The result is something remarkable a genuinely new book about sex. The book is a pioneering analysis of the evolutionary biology of human sexuality, proposing that all aspects have been shaped by the phenomenon of sperm competition.
This book further discusses the remarkable potential for sperm competition. As often put, for males its like trying to win the. Parker was invited to a us symposium organised by bob smith. Sperm competition and the evolution of animal mating systems. That topic continues with bob smiths sperm competition. The ubiquity and power of male sexual jealousy provides evidence of an evolutionary history of female infidelity and thus perhaps also of sperm competition. Over the years, human sperm competition has become a classic in the study of human sexual biology but although the original hardback is still in print rising costs plus perhaps its classic status have priced it beyond those students who might most wish to read its contents. It is pretty good reading if you are interested in human sperm competition. And the results of those unique experiments were presented in human sperm competition and nowhere else. For example, the shape of the human penis may have been selectively shaped by sperm competition. This book discusses these implications for human sexual behaviour and. Wife sharing or cuckolding is one of the most common fantasies among men and it turns out it may actually increase a womans ability to get pregnant by creating sperm competition syndrome.
Sperm competition is possible in homo sapiens, though whether it has played a significant role during human evolution remains highly debatable, dr. Sexual selection from sperm competition is expected to favor opposing adaptations in males that function either in the avoidance of sperm competition by guarding females from rival males or in the engagement in sperm competition by. Copulation, masturbation and infidelity, human sperm competition, mark a. This sperm competition is probably both a lottery and a race, but more than anything it could also be a war, with sperm of different morphologies playing different roles. But until human sperm competition there had never been a discussion of the. On the one hand, the risk that sperm may find themselves in competition with the sperm from another male. Behavioural ecologists and evolutionary biologists have for a number of years been interested in the biological implications of sperm from different males competing for fertilization of the egg in the female tract. Baker and bellis may not be always right, but it is a hell of a good story. Classic and contemporary readings 9780387280363 and a great selection of similar new, used and collectible books available now at great prices. Human sperm competition copulation masturbation and. Apr 30, 2018 for every single feature indicating adaptation for sperm competition in chimpanzees humans show a contrasting condition. As evidence that semen coagulation may have emerged in part as a sperm competition tactic that functions to block sperm from rival males, dixon and anderson 2002 examined semen coagulation and copulatory plugs in 40 species of primates. Most strikingly, human semen just like that of gorillas contains.
Copulation, masturbation and infidelity by baker, r robin. In the second half, the mechanism of sperm competition is evaluated in detail, together with the evidence for and the implications of the authors own kamikaze sperm hypothesis. Sexual selection from sperm competition is expected to favor opposing adaptations in males that function either in the avoidance of sperm competition by guarding females from rival males or in the engagement in sperm competition by increased. Battle of the sexes is discerned in sperm the new york times. Males have adapted to battle with competing sperm date. In fact, sperm competition is a wellsupported idea that goes way back. Levels of human sperm competition, male adjustment of ejaculates, function of the female orgasm, penis shape, variation in testes size, female. Human sperm competition ebook por robin baker 9788461686506. Consequently, the extent to which sperm competition occurred in ancestral human populations would have depended on rates of female sexual infidelity.
Nicholas pound presents various ways in which sperm compete to fertilize eggs and how this has prompted reinterpretations of breeding behavior from a biological perspective. Sperm competition and the evolution of animal mating systems 1st. Sperm competition goes back to the beginning of mankind. Human sperm competition copulation, masturbation and. I had been asking sex questions on a human evolution group, and was told more than once to read sperm wars. Sperm competition sperm competition is a term used to refer to the competitive process between the sperm of two or more different males to fertilize an egg of a lone female.
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