Sperm Competition In Humans PDF Download
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| Author | : Todd K. Shackelford |
| Publisher | : Springer |
| Total Pages | : 0 |
| Release | : 2010-10-29 |
| Genre | : Science |
| ISBN | : 9781441939173 |
Download Sperm Competition in Humans Book in PDF, ePub and Kindle
In species with internal fertilization, sperm competition occurs when the sperm of two or more males simultaneously occupy the reproductive tract of a female and compete to fertilize an egg (Parker, 1970). A large body of empirical research has demonstrated that, as predicted by sperm competition theory, males and females in many species possess anatomical, behavioral, and physiological adaptations that have evolved to deal with the adaptive challenges associated with sperm competition. Moreover, in recent years, evolutionary biologists and psychologists have begun to examine the extent to which sperm competition may have been an important selective pressure during human evolution. Some research has suggested that male humans, like males of many bird, insect, and rodent species, might be able to adjust the number of sperm they inseminate according to the risk of sperm competition. Other research has examined whether such responses might be accompanied by psychological changes that motivate human males to pursue copulations when the risk of sperm competition is high. Furthermore, there is research suggesting that aspects of human penile anatomy might function to enhance success in sperm competition. Much of this work has been controversial; some of the findings have been disputed and others have been greeted with skepticism. However, the idea that some aspects of human psychology and behavior might best be understood as adaptations to sperm competition remains intriguing and, in certain cases, very persuasive.
| Author | : R.R. Baker |
| Publisher | : Springer |
| Total Pages | : 354 |
| Release | : 1994-12-31 |
| Genre | : Science |
| ISBN | : 0412454300 |
Download Human Sperm Competition Book in PDF, ePub and Kindle
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. This book discusses these implications for human sexual behaviour and human infertility problems.
| Author | : Todd K. Shackelford |
| Publisher | : Springer Science & Business Media |
| Total Pages | : 299 |
| Release | : 2006-11-22 |
| Genre | : Science |
| ISBN | : 0387280391 |
Download Sperm Competition in Humans Book in PDF, ePub and Kindle
In species with internal fertilization, sperm competition occurs when the sperm of two or more males simultaneously occupy the reproductive tract of a female and compete to fertilize an egg (Parker, 1970). A large body of empirical research has demonstrated that, as predicted by sperm competition theory, males and females in many species possess anatomical, behavioral, and physiological adaptations that have evolved to deal with the adaptive challenges associated with sperm competition. Moreover, in recent years, evolutionary biologists and psychologists have begun to examine the extent to which sperm competition may have been an important selective pressure during human evolution. Some research has suggested that male humans, like males of many bird, insect, and rodent species, might be able to adjust the number of sperm they inseminate according to the risk of sperm competition. Other research has examined whether such responses might be accompanied by psychological changes that motivate human males to pursue copulations when the risk of sperm competition is high. Furthermore, there is research suggesting that aspects of human penile anatomy might function to enhance success in sperm competition. Much of this work has been controversial; some of the findings have been disputed and others have been greeted with skepticism. However, the idea that some aspects of human psychology and behavior might best be understood as adaptations to sperm competition remains intriguing and, in certain cases, very persuasive.
| Author | : Robin Baker |
| Publisher | : Basic Books |
| Total Pages | : 401 |
| Release | : 2006-01-03 |
| Genre | : Psychology |
| ISBN | : 0465012965 |
Download Sperm Wars Book in PDF, ePub and Kindle
This classic work on the rules of sex -- updated for a new generation -- is still as provocative as the day it was published, providing simple explanations for any and all questions about what happens in the bedroom. Sex isn't as complicated as we make it. In Sperm Wars, evolutionary biologist Robin Baker argues that every question about human sexuality can be explained by one simple thing: sperm warfare. In the interest of promoting competition between sperm to fertilize the same egg, evolution has built men to conquer and monopolize women while women are built to seek the best genetic input on offer from potential sexual partners. Baker reveals, through a series of provocative fictional scene, the far-reaching implications of sperm competition. 10% of children are not fathered by their "fathers;" over 99% of a man's sperm exists simply to fight off all other men's sperm; and a woman is far more likely to conceive through a casual fling than through sex with her regular partner. From infidelity, to homosexuality, to the female orgasm, Sperm Wars turns on every light in the bedroom. Now with new material reflecting the latest research on sperm warfare, this milestone of popular science will still surprise, entertain, and even shock.
| Author | : Tim Birkhead |
| Publisher | : Harvard University Press |
| Total Pages | : 300 |
| Release | : 2000 |
| Genre | : Science |
| ISBN | : 9780674006669 |
Download Promiscuity Book in PDF, ePub and Kindle
Birkhead reveals a world in which males and females vie with each other as they strive to maximize their reproductive success. Color illustrations.
| Author | : Todd K. Shackelford |
| Publisher | : Oxford University Press |
| Total Pages | : 368 |
| Release | : 2012-01-04 |
| Genre | : Psychology |
| ISBN | : 0199908303 |
Download The Oxford Handbook of Sexual Conflict in Humans Book in PDF, ePub and Kindle
Sexual conflict -- what happens when the reproductive interests of males and females diverge -- occurs in all sexually reproducing species, including humans. The Oxford Handbook of Sexual Conflict in Humans is the first volume to assemble the latest theoretical and empirical work on sexual conflict in humans from the leading scholars in the fields of evolutionary psychology and anthropology. Following an introductory section that outlines theory and research on sexual conflict in humans and non-humans, ensuing sections discuss human sexual conflict and its manifestations before and during mating. Chapters in these sections address a range of factors topics and factors, including: - Sexual coercion, jealousy, and partner violence and killing - The ovulatory cycle, female orgasm, and sperm competition - Chemical warfare between ejaculates and female reproductive tracts Chapters in the next section address issues of sexual conflict after the birth of a child. These chapters address sexual conflict as a function of the local sex ratio, men's functional (if unconscious) concern with paternal resemblance to a child, men's reluctance to pay child support, and mate expulsion as a tactic to end a relationship. The handbook's concluding section includes a chapter that considers the impact of sexual conflict on a grander scale, notably on cultural, political, and religious systems. Addressing sexual conflict at its molecular and macroscopic levels, The Oxford Handbook of Sexual Conflict in Humans is a fascinating resource for the study of intersexual behavior.
| Author | : Robert L. Smith |
| Publisher | : Elsevier |
| Total Pages | : 710 |
| Release | : 2012-12-02 |
| Genre | : Science |
| ISBN | : 032314313X |
Download Sperm Competition and the Evolution of Animal Mating systems Book in PDF, ePub and Kindle
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 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. The following chapter describes the relationship between multiple mating and female fitness, with an emphasis on determining the conditions under which selection on females is likely to counteract selection on males for avoiding sperm competition. Other chapters consider the female perspective on sperm competition; the evolutionary causation at the level of the individual male gamete; and the correlation of high paternal investment and sperm precedence in the insects. The remaining chapters are arranged phylogenetically and explore the sperm competition in diverse animal taxa, such as the Drosophila, Lepidoptera, spiders, amphibians, and reptiles. These chapters also cover the evolution of direct versus indirect sperm transfer among the arachnids or the problem for kinship theory presented by multiple mating and sperm competition in the Hymenoptera. This book further discusses the remarkable potential for sperm competition among certain temperate bat species whose females store sperm through winter hibernation and the mixed strategies and male-caused female genital trauma as possible sperm competition adaptations in poeciliid fishes. The concluding chapter examines the predictions concerning testes size and mating systems in the primates and the possible role of sperm competition in human selection. This book is of great value to reproductive biologists and researchers.
| Author | : Scott S. Pitnick |
| Publisher | : Academic Press |
| Total Pages | : 683 |
| Release | : 2008-11-21 |
| Genre | : Science |
| ISBN | : 0080919871 |
Download Sperm Biology Book in PDF, ePub and Kindle
Sperm Biology represents the first analysis of the evolutionary significance of sperm phenotypes and derived sperm traits and the possible selection pressures responsible for sperm-egg coevolution. An understanding of sperm evolution is fast developing and promises to shed light on many topics from basic reproductive biology to the evolutionary process itself as well as the sperm proteome, the sperm genome and the quantitative genetics of sperm. The Editors have identified 15 topics of current interest and biological significance to cover all aspects of this bizarre, fascinating and important subject. It comprises the most comprehensive and up-to-date review of the evolution of sperm and pointers for future research, written by experts in both sperm biology and evolutionary biology. The combination of evolution and sperm is a potent mix, and this is the definitive account. The first review survey of this emerging field Written by experts from a broad array of disciplines from the physiological and biomedical to the ecological and evolutionary Sheds light on the intricacies of reproduction and the coevolution of sperm, egg and reproductive behavior
| Author | : Alan F. Dixson |
| Publisher | : Oxford University Press, USA |
| Total Pages | : 229 |
| Release | : 2009-05-14 |
| Genre | : Medical |
| ISBN | : 0199559422 |
Download Sexual Selection and the Origins of Human Mating Systems Book in PDF, ePub and Kindle
This book demonstrates how detailed comparative analyses of the anatomy, reproductive physiology, and behaviour of non-human primates and other mammals can offer profound insights into the origins of human sexual behaviour.
| Author | : Alex Bezzerides |
| Publisher | : Harlequin |
| Total Pages | : 230 |
| Release | : 2021-05-18 |
| Genre | : Health & Fitness |
| ISBN | : 1488075859 |
Download Evolution Gone Wrong Book in PDF, ePub and Kindle
“An unforgettable journey through this twisted miracle of evolution we call ‘our body.’” —Spike Carlsen, author of A Walk Around the Block From blurry vision to crooked teeth, ACLs that tear at alarming rates and spines that seem to spend a lifetime falling apart, it’s a curious thing that human beings have beaten the odds as a species. After all, we’re the only survivors on our branch of the tree of life. The flaws in our makeup raise more than a few questions, and this detailed foray into the many twists and turns of our ancestral past includes no shortage of curiosity and humor to find the answers. Why is it that human mothers have such a life-endangering experience giving birth? Why are there entire medical specialties for teeth and feet? And why is it that human babies can’t even hold their heads up, but horses are trotting around minutes after they’re born? In this funny, wide-ranging and often surprising book, biologist Alex Bezzerides tells us just where we inherited our adaptable, achy, brilliant bodies in the process of evolution.
