Książki

Biology of Sex is a lively and intellectually challenging textbook. Mills analyzes the biological basis of sex by considering genetic, physiological, and evolutionary principles. In order to explain the biological aspects of human sex, he uses direct and intriguing comparisons with the many variations in sexual systems among non-human organisms. Text boxes provide fascinating examples: non-human species that cannibalize their partners during copulation, organisms that do not fall within one of two biological sexes, and species that "trick" others into raising their young. The author also explores questions such as: "Is sex only for reproduction?", "Why is sex pleasurable?", and "What are the roots of sexual conflict?" Intended primarily for readers without a science background, Biology of Sex provides novel content from the human and non-human worlds to introduce the complex subject of sex and reproduction.

Biology of Sex

List of Figures

List of Boxes

Preface





1. Introduction

Key themes

1.1 The wider context: sex, gender, sexuality, and sexual orientation

1.1.1 Assigned sex and gender dysphoria

1.1.2 Sex as a biological construct and gender as a social construct

1.2 A caveat about biological determinism and ideology

1.3 The comparative approach

1.4 Biology as a part of natural science

1.5 Theories and the methodology of science

Summary

Further reading





2. Sex and Reproduction

Key themes

2.1 Does sexual motivation reveal its "purpose"?

2.1.1 Sex has diverse purposes through co-option

2.1.2 Homosexuality could be one manifestation of co-option

2.1.3 Sexual features can also be co-opted for non-social purposes

2.2 Reproduction: sexual, asexual, and non-sexual

2.2.1 Not all organisms reproduce sexually

2.2.2 Non-sexual reproductions of human cells is through mitosis and cytokinesis

2.2.3 Asexual reproduction in complex organisms

2.2.4 Switching between parthenogenesis and sexual reproduction

2.3 Sexual reproduction fundamentals

2.3.1 Female and male: Eggs and sperm

2.3.2 Primary versus secondary sex characteristics

2.4 From fertilization to the production of offspring

2.4.1 External versus internal fertilization

2.4.2 Other variations in patterns of sexual reproduction

Summary

Further reading





3 Sex and Inheritance

Key themes

3.1 How an Augustinian friar discovered the rules of sexual inheritance

3.1.1 Mendel's peas were a "friendly" study system

3.2 Developing Mendel's Law of Segregation

3.2.1 The second-generation offspring showed a surprising pattern of inheritance

3.2.2 The meaning of segregation in the making of gametes

3.3 Mendel's Law of Independent Assortment

3.4 Updating Mendelian genetics

3.4.1 Using modern terminology

3.5 Applying Mendelian genetics to humans

3.5.1 Mendelian inheritance of blood groups in humans

3.6 Sex, DNA, and chromosomes

3.6.1 Chromosomes are the hereditary material

3.6.2 The human karyotype

3.6.3 DNA is the genetic code

3.6.4 How DNA encodes information

3.7 What happens to chromosomes in the making of gametes?

3.7.1 What is crossing-over?

3.7.2 The two divisions of meiosis

3.7.3 Sex and chromosomes that don't crossover

3.7.4 How meiosis relates to Mendel's laws

Summary

Further reading





4. Sex and Evolution

Key themes

4.1 A short history of evolutionary thought

4.1.1 Evolutionary theory is a natural result of the Enlightenment

4.1.2 Exploration, fossils, and a very old Earth also led to evolutionary theory

4.1.3 Jean-Baptiste Lamarck proposed a mechanism for evolution in 1809

4.1.4 Charles Darwin and the voyage of the Beagle

4.2 The principles of natural selection

4.2.1 The argument for natural selection

4.2.2 The concepts of fitness and adaptation

4.3 DNA as an evolutionary legacy

4.3.1 Mutations, and how alleles differ from one another

4.3.2 Chromosomal mutations can also contribute to evolution

4.3.3 Mutation rates in sperm and eggs

4.4 Thinking of breeding groups as gene pools

4.4.1 Human breeding groups can be thought of as gene pools

4.4.2 The ABO blood group gene pool

4.5 The evolutionary costs of sex

4.5.1 The numerical argument that sex is costly

4.5.2 Sexual reproduction also involves search costs

4.5.3 Sexual reproduction can entail health, injury, and mortality costs

4.6 The evolutionary benefits of sex

4.6.1 Advantages associated with a diverse gene pool

4.6.2 Inbreeding reveals the value of gene mixing through sex

4.6.3 The Red Queen hypothesis and Muller's ratchet

4.7 The role of sex in the creation of species

4.7.1 Two different patterns of species evolution

4.7.2 How do gene pools become split at the start of speciation?

4.7.3 Pre-zygotic and post-zygotic reproductive barriers

Summary

Further reading





5. Sexual Selection

Key themes

5.1 Sexual selection is a sub-category of natural selection

5.1.1 Comparing examples of natural selection and sexual selection

5.1.2 Re-formulating the natural selection argument for sexual selection

5.1.3 Manifestations of sexual selection

5.2 Why are females usually the "limiting sex"?

5.2.1 Females usually invest more in reproduction

5.2.2 Does inter-sexual selection produce payoffs?

5.2.3 Does intra-sexual selection produce payoffs?

5.3 How mate choice based on ornaments increases female fitness

5.3.1 Genetic benefits in the runaway hypothesis: "Sexy sons"

5.3.2 Genetic benefits in the good genes hypothesis: Better survival

5.3.3 Benefits in the good resources hypothesis: Honest promises

5.4 Sex role reversal

5.4.1 Sex role reversal: Adjusting investments made by males and females

5.5 Not all intra-sexual competition involves fighting

5.5.1 Scrambles are a form of indirect competition

5.5.2 Endurance and subterfuge are also forms of indirect competition

5.5.3 Sperm competition

Summary

Further reading





6. Mating Systems

Key themes

6.1 There are five major types of mating systems

6.2 Monogamy

6.2.1 Distinguishing among types of monogamy

6.2.2 Hypotheses for monogamy

6.3 Polygyny is the most common form of polygamy

6.3.1 Two models for polygyny

6.3.2 Human polygyny

6.4 The benefits for females of mating with multiple males

6.4.1 Non-monogamous females hedge their bets against infertility

6.4.2 Non-monogamous females reap genetic benefits

6.4.3 Non-monogamous females can reap direct benefits

6.5 Polyandry

6.5.1 Polyandrous mating systems are much less common than polygynous ones

6.6 Polygynandry

6.6.1 Reproductive skew

6.6.2 Cooperative breeding

6.7 Promiscuity

6.7.1 Factors associated with promiscuity

6.7.2 Scramble competitions are usually promiscuous mating systems

6.7.3 "Lek polygyny" is a promiscuous system resembling hook-up culture

Summary

Further reading





7. Sexual Conflict

Key themes

7.1 Strategies for sexual success

7.1.1 A comment on terminology

7.1.2 Sexual strategies exist in the context of sexual conflict

7.2 Realms of sexual conflict

7.2.1 Sexual conflict before mating

7.2.2 Sexual conflict during mating

7.2.3 Sexual conflict after mating

7.2.4 Sexual conflict during parenting

7.3 Mating strategies can change with circumstances

7.3.1 Making the best of things

7.3.2 Life history theory argues for plastic mating strategies

7.3.3 Sex allocation

7.4 Same-sex parenting

Summary

Further reading





8. Sex Determination and Differentiation

Key themes

8.1 Are male and female bodies the only two options in sex determination?

8.2 The familiar method of sex determination relies on X- and Y-chromosomes

8.2.1 Using insects to discover the role of sex chromosomes

8.2.2 The X- and Y-chromosomes in humans

8.2.3 Little genetic differences between men and women, but big phenotypic differences

8.2.4 The SRY gene and transcription

8.3 Not all genetic sex determination relies on the XY system

8.3.1 Genetic sex determination without Y-chromosomes

8.3.2 Are females ever the heterogametic sex?

8.3.3 Chromosomal sex determination where hermaphroditism is a phenotype

8.3.4 Genetic sex determination in honeybees

8.4 Environmental sex determination

8.4.1 Temperature is a non-social sex-determination system

8.4.2 Environmental sex determination can override genetic sex determination

8.4.3 Can mothers use temperature to select their offspring's sex?

8.4.4 Social systems of environmental sex determination

8.4.5 Anomalous sex determination caused by a member of a different species

8.4.6 Anomalous sex determination by ecotoxins

Summary

Further reading





9. Human Sexual Anatomy and Regulation

Key themes

9.1 Human sexual differentiation and function is highly dependent on hormones

9.1.1 The endocrine system regulates hormones in the bloodstream

9.1.2 Major hormones that regulate sexual development, function, and behavior

9.2 Sex differentiation is part of development

9.2.1 Human sexual differentiation before birth

9.3 The male reproductive system

9.3.1 Further male differentiation during the prenatal period

9.3.2 Male sexual development at puberty

9.3.3 Sexual anatomy of the human adult male

9.4 The female reproductive system

9.4.1 Further female differentiation during the prenatal period

9.4.2 Female sexual differentiation at puberty

9.4.3 Sexual anatomy of the human adult female

9.5 Anomalous sexual phenotypes in humans

9.5.1 Consequences of anomalies in the sex chromosomes

9.5.2 Intersex conditions that result from dysfunctional alleles

9.5.3 When girls become men at puberty

9.6 Sex linkage: Why some genetic disorders occur mostly in males

9.7 Cancers of sexually differentiated organs and tissues

9.7.1 Cancers associated with male organs

9.7.2 Cancers associated with female organs

Summary

Further reading





10. Human Fertility and Birth

Key themes

10.1 Key differences between making sperm and eggs

10.1.1 Spermatogenesis occurs from puberty to old age

10.1.2 Oogenesis occurs from the fetal stage to menopause

10.2 The menstrual cycle

10.2.1 Most mammals have an estrous cycle instead

10.2.2 Is women's fertile period concealed?

10.3 Sexual arousal and response in men and women

10.4 Fertilization and the making of a zygote

10.4.1 Infertility

10.4.2 Contraception

10.5 Pregnancy

10.5.1 The placenta

10.5.2 Labor and delivery

10.6 Breast-feeding

10.7 Menopause

10.8 Sexually transmitted infections

10.8.1 A diversity of organisms cause STIs

10.8.2 Major bacterial STIs

10.8.3 Major STIs caused by viruses

10.8.4 Non-humans suffer sexually transmitted infections too

Summary

Further reading





Glossary

Index