Human Sperm Competition , livre ebook

HARD NUT Books - Robin Baker

Découvre YouScribe en t'inscrivant gratuitement

Je m'inscris

Obtenez un accès à la bibliothèque pour le consulter en ligne
En savoir plus

505 pages

English

Obtenez un accès à la bibliothèque pour le consulter en ligne
En savoir plus

A propos
Informations
Extrait

Description

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. 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 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. Written 20 years ago in 1993-94, the print edition was published in 1995. Despite its age that book's contents are as relevant now as they were two decades ago. Perhaps even more so, because since Baker and Bellis' demonstration that human sperm competition could actually be studied in a variety of ways a number of research groups have taken up the challenge where they left off. Most of these groups have obtained results that build firmly upon Baker and Bellis' original work. A few others created important dialogues. None though have destroyed any crucial part of the foundation first laid down in that 1995 book. But the main way in which Human Sperm Competition remains relevant to this day is that for various reasons - some cultural, some procedural, and yet others due to sheer opportunity - Baker and Bellis were able to do a number of experiments that others since have not had the opportunity to repeat. And the results of those unique experiments were presented in Human Sperm Competition and nowhere else.In the first half of the book the authors explore the role of sperm competition in the evolution of human sexual characteristics, considering for example the architecture of the female reproductive tract, the reasons for male and female infidelity and the possible biological reasons for homosexuality, masturbation and orgasm.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. Human Sperm Competition sets out the thesis that adopting an evolutionary approach to human reproduction exposes the subtle and sophisticated ways in which human sexual anatomy, physiology and behaviour are designed to interact. As a species, understanding this sexual legacy helps explain how we reproduce today and why problems with fertility arise.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. This digital edition of the original 1995 publication, but at a student-friendly price, now solves this problem.

Sujets

Sciences et techniques

Human biology

Informations

Publié par	HARD NUT Books
Date de parution	16 juin 2014
Nombre de lectures	1
EAN13	9788461686506
Langue	English
Poids de l'ouvrage	5 Mo

Informations légales : prix de location à la page 0,0250€. Cette information est donnée uniquement à titre indicatif conformément à la législation en vigueur.

Extrait

Human Sperm Competition
Copulation, masturbation andinfidelity
By Robin Baker and Mark A. Bellis
Digitaledition first published by HARD NUT books, 2014

Email: hardnutbooks@gmail.com
ISBN978-84-616-8650-6
Copyright © R. RobinBaker & Mark A. Bellis 1995
www.robin-baker.com
mabellis@me.com
RobinBaker and Mark Bellis have asserted their right under the Copyright, Designsand Patents Act 1988 to be identified as the authors of this work.
Robin Baker isrepresented by:
TheSusijn Agency
3rd Floor, 64 GreatTitchfield Street, London, W1W 7QH, UK
www.thesusijnagency.com
Cover
Thecover illustration shows a scanning electron micrograph of two sperm (onecoiled, one normal) and a leucocyte from the female, all taken from a woman’sreproductive tract post-copulation.
Photograph by MarkBellis and Gill Douglas
About the Authors
Robin Baker
Born in Wiltshire, England, in 1944, Robin Bakergrew up in the small village of Manningford Bruce in the Vale of Pewsey. Afterobtaining a First Class Honours degree in Zoology (1965), then a PhD, at theUniversity of Bristol (1968), he lectured in Zoology for over 25 years at theUniversities of first Newcastle-upon-Tyne and then Manchester. At Manchester hewas Reader in Zoology in the School of Biological Sciences from 1981-1996. In1996 he left academic life to concentrate on his career in writing and broadcasting.A best-selling author in the field of sexual biology, his books (6 academic, 4popular science, and 3 novels) have been translated into 28 differentlanguages. He has also published around 100 scientific papers and articles andhis work and ideas on the evolution of human behaviour have been featured inmany radio and television programmes around the world. Since 2002 he has livedin the foothills of the Spanish Sierras with his partner and their family. Hehas six children and three grandchildren.
Mark A. Bellis
After working for many years on the evolution ofhuman behaviour, Mark turned his behavioural research to the improvement ofpopulation health. Since then he has led national and international researchprogrammes to tackle alcohol and drug misuse, improve sexual health and preventviolence. He has published over 140 academic papers primarily on therelationships between human behaviour and health, and as Professor of PublicHealth at Liverpool John Moores University established and directed one of theUK's largest public health research departments. Professor Bellis is nowDirector of Policy, Research and Development for Public Health Wales; leadingdevelopments in public health policy nationally and working internationallywith bodies including the World Health Organization and other arms of theUnited Nations. Mark is visiting Professor of Public Health at Liverpool JohnMoores University and holds honorary chairs in the Schools of Medicine at bothCardiff and Swansea Universities.
Dedications
RRB
To Liz, for beingopen-minded, and
to Nathanial, forbeing the first flowback baby
MAB
Tomy wife Georgie and my children Aaron, Jack and Molly
– my whys and thewherefores
Tableof Contents
About the Authors
Dedications
Table of Contents
Frontispiece
Preface to Digital (2014) Publication
Preface to Original (1995)Publication
Acknowledgements
1 Introduction
2 Sex, coyness and promiscuity: theevolution of sperm competition
2.1 Introduction
2.2 Evolutionary inheritance: aprogramme for a lifetime
2.3 Human sexuality: the basics
2.3.1 Sex, gender and the sex ratio
2.3.2 Urgent males and coy females
2.4 Polyandry and sperm competition:a pre-vertebrate legacy
2.4.1 Polyandrous females
2.4.2 Sperm competition anddouble-mating
2.4.3 Spermatogenesis and male spermstorage organs
2.4.4 Mate-guarding by males
2.5 Sperm competition theory
2.5.1 The lottery principle
2.5.2 Sperm size and competitiveness
2.5.3 Sperm warfare and the KamikazeSperm Hypothesis
2.5.4 Restraint in sperm ejaculation
2.5.5. How many sperm should beejaculated?
2.5.6 Females should promote spermcompetition
Boxes for Chapter 2
Box 2.1 A suggested history of thedifferent facets of human sexuality
Box 2.1a A suggested course for thehuman lineage during its pre-vertebrate phase of evolution (adapted fromMargolis 1981).
Box 2.2 Reproduction: the currency ofnatural selection
Box 2.3 Sexual reproduction
Box 2.4 Anisogamy and the male-femalephenomenon
Box 2.5 Evolution and maintenance ofa 1:1 sex ratio
Box 2.6 A nationwide survey (1989) ofthe level of polyandry and other sexual behaviour of British females
Box 2.7 Urgent males; coy females
Box 2.8 Polyandrous females: modes ofsexual activity
Box 2.9 Minimum time intervalsbetween successive copulations with two different males by females at differentlevels of sexual experience
Box 2.10 Sperm production and storage(In part adapted from Johnson and Everitt, 1988)
Box 2.11 The efficiency and evolutionof mate-guarding by males
Box 2.12 Sexy sons, sexy daughtersand handicaps: the successful child principle in the evolution of female sexualbehaviour
3 Legacies from the age of reptiles:copulation, flowback and the female orgasm
3.1 Introduction
3.2 Internal fertilization andsexually transmitted diseases
3.3 The male: copulation, seminalfluids and copulatory plugs
3.3.1 Intromittent organs andcopulation
3.3.2 Seminal fluids
3.3.3 Copulatory plugs
3.3.4 The antiquity of copulation andinsemination in the human lineage
3.4 Forced copulation
3.5 The female: sperm storage organs,flowbacks and copulatory orgasms
3.5.1 Sperm storage organs in thefemale
3.5.2 The flowback: female ejectionof sperm
3.5.3 Female copulatory orgasm
3.5.4 The antiquity of sperm storageand manipulation by females of the human lineage
Boxes for Chapter 3
Box 3.1 A suggested course for thehuman lineage during its premammalian phase of vertebrate evolution. (Adaptedfrom Pough et al., 1990.)
Box 3.2 In vitro fertilization (IVF)and embryo transfer (ET)
Box 3.3 The behavioural ecology ofrape
Box 3.4 The reproductive tract of thehuman female
Box 3.5 Cervical mucus
Box 3.6 The evolution of spermstorage organs in females
Box 3.7 Written instructions for thecollection of flowback samples
Box 3.8 A direct study of wholeejaculates and flowbacks
Box 3.9 The subjective estimation offlowback volume
Box 3.10 Frequency distribution ofnumber of sperm in whole inseminates (collected by condom) and ejected inflowbacks
Box 3.11 Ejection of flowback byfemale Grevy’s zebra
Box 3.12 Course and timing of femalecopulatory orgasms in humans
4 The mammalian inheritance: maternalcare, family planning, and sperm polymorphism
4.1 Introduction
4.2 Maternal care, viviparity andlactation
4.2.1 Maternal care and lactation
4.2.2 Viviparity and pregnancy
4.3 The female tract: the arena forsperm competition
4.4 Family planning andcontraception: the female perspective
4.4.1 Contraception: avoidingcopulation
4.4.2 Contraception: prepuberty andmenopause
4.4.3 Contraception: avoidingovulation from puberty to menopause
4.4.4 Contraception: copulation atinfertile stages of fertile menstrual cycles
4.4.5 Contraception: short-lived eggs
4.4.6 Contraception: sperm longevityin the female tract
4.4.7 Contraception: the timing ofovulation
4.4.8 Contraception: control of spermnumbers
4.4.9 Avoiding pregnancy: failure toimplant
4.4.10 Avoiding development:polyspermy
4.4.11 Avoiding birth: spontaneousabortion
4.4.12 Avoiding maternal care:infanticide
4.4.13 Optimizing family structure:influencing the sex ratio
4.4.14 Optimizing family structure:influencing paternity after insemination
4.4.15 Optimizing family structure:producing helpers
4.4.16 Antiquity of female familyplanning
4.5 Male genitalia: size and locationof testes
4.5.1 Testis size
4.5.2 Testis location
4.6 Sperm polymorphism
4.7 Ordered ejaculates
Boxes for Chapter 4
Box 4.1 A suggested course for thehuman lineage during its mammalian phase of evolution (Redrawn and adapted fromNovacek, 1992)
Box 4.2 The behavioural ecology ofparental care
Box 4.3 Maternal care in the animalkingdom
Box 4.4 Lactation, breasts andnipples
Box 4.5 Viviparity, pregnancy and theplacenta
Box 4.6 Ovulation and menstruation:the menstrual cycle
Box 4.7 Energetics of femalereproduction: fat distribution, body weight and nutrition
Box 4.8 Variation in copulation rate
Box 4.9 The duration of maternal careand the evolution of puberty
Box 4.10 Anovulatory menstrual cycles
Box 4.11 Longevity of mammalian sperm
Box 4.12 Spontaneous and inducedovulation in mammals
Box 4.13 Spontaneous abortion
Box 4.14 Sex ratio of offspring as afunction of social status: the Trivers-Willard hypothesis
Box 4.15 Parental manipulation
Box 4.16 Down’s syndrome: sterilehelpers?
Box 4.17 Male-male variation intestis size, rate of sperm production and involvement in sperm competition
Box 4.18 Testis location
Box 4.19 Sperm shape and polymorphismin humans and other mammals
Box 4.20 A study of sperm in the differentspurts of the human ejaculate
5 The mammalian inheritance:masturbation, homosexuality and push buttons
5.1 Introduction
5.2 Orgasms in a lifetime
5.3 Types of non-copulatory orgasms
5.3.1 Spontaneous (nocturnal) orgasms
5.3.2 Self-masturbation
5.3.3 Heterosexually stimulatednon-copulatory orgasms
5.3.4 Homosexually stimulatednon-copulatory orgasms
5.4 Interaction between copulationand the different types of non-copulatory orgasm
5.5 The distribution ofnon-copulatory orgasms through the menstrual cycle in females
5.6 The function of non-copulatoryorgasms
5.6.1 Behavioural polymorphism
5.6.2 Male self-masturbation andnocturnal emission
5.6.3 Female self-masturbation andnocturnal orgasm
5.6.4 Orgasm crypsis
5.6.5 Homosexuality
5.7 ‘Push-buttons’: the clitoris,nipples and masturbation
5.7.1 Push-button power
5.7.2 The evolutionary history ofmale nipples
5.7.3 The evolutionary his