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Chapter 1: The Nature of Science & The Nature of Sex
1.1 Chapter Objectives
1.2 Nature of Science Overview
1.3 Experimental Design
1.4 Interpreting Data
1.5 Stating a Hypothesis
1.6 Correlation Does Not Equal Causation
1.7 Exploring Correlations
1.8 Human Papillomavirus (HPV) and Cervical Cancer
1.9 Does the HPV vaccine lead to more sex in teenagers?
1.10 Science is a social endeavor
1.11 Wrapping Up: Why use sex to study biology?
Chapter 2: Evolution
2.1 Chapter Objectives
2.2 Evolution Overview
2.3 What is NOT evolution?
2.4 How do we know evolution has occurred? Fossil evidence.
2.5 How do we know evolution has occurred? Comparative anatomy.
2.6 How do we know evolution has occurred? Genetic evidence.
2.7 How do we know evolution has occurred? Biogeography.
2.8 The Importance of Variation
2.9 Mechanisms of Evolution: Gene Flow
2.10 Mechanisms of Evolution: Genetic Drift
2.11 Mechanisms of Evolution: Natural Selection
2.13 Sexual Selection
2.14 Mechanisms of Evolution Overview
2.15 Biodiversity & Adaptive Radiation
2.16 Species & Phylogenetic Trees
2.17 Wrapping Up: Are Humans Evolving?
Chapter 3: The Ingredients of Life
3.1 Chapter Objectives
3.2 What are living things made of?
3.4 Nucleic Acids
3.5 Amino Acids
3.6 Fatty Acids
3.8 Looking Closer at Organelles
3.9 Wrapping Up: Revisiting the Egg
Chapter 4: The Essentials of Genetics
4.1 Chapter Objectives
4.2 An Overview of Basic Genetics
4.3 Genotype to Phenotype
4.4 Genes Get Around
4.5 Oral sex in cichlid fishes
4.6 See for Yourself
4.7 Wrapping Up: The Science of Paternity Testing
Chapter 5: Express Yourself! From DNA to Protein
5.1 Chapter Objectives
5.2 The Genetic Basis of Gene Expression
5.3 Protein Synthesis Requires RNA
5.4 RNA is Transcribed from a DNA Template
5.5 RNA is Translated into a Polypeptide
5.6 What are proteins?
5.7 Proteins Take on Many Roles
5.8 Using the genetic code
5.9 Many Genes are Highly Conserved
5.10 Point Mutations Affect Gene Expression
5.11 Gene Regulation
5.12 Wrapping Up: The Mystery of Monogamy
Chapter 6: Life Cycles, Cell Division, and Inheritance
6.1 Chapter Objectives
6.2 Sex generates genetic diversity
6.3 Mitosis is how most of our cells divide
6.4 Meiotic division results in sex cells
6.5 Meiosis I
6.6 Meiosis II
6.7 Further genetic diversity is generated through crossing over
6.8 Pulling the pieces together
6.9 Recessive traits are expressed when two copies are present
6.10 Dominant alleles can mask recessive alleles
6.11 Calculating the odds of inheritance
6.12 Sex chromosomes
6.13 Sex-linked inheritance
6.14 Moving beyond single-gene effects
6.15 Wrapping up: A return to cloning labs
Chapter 7: Why Sex?
7.1 Chapter Objectives
7.2 Sex is a Problem
7.3 Does sex lead to fewer mutations?
7.4 The Red Queen
7.5 Testing the Red Queen Hypothesis
7.6 Major Histocompatibility Complex (MHC) Proteins
7.7 Sniffing Out Complementarity in Humans
7.8 Wrapping Up: Sex and the Single Whiptail Lizard
Chapter 8: Sex and Gender
8.1 Chapter Objectives
8.2 Male versus Female
8.3 What Distinguishes the Sexes?
8.4 Sex: It’s About the Gametes
8.5 Mechanisms of Sex Determination
8.6 Human Sex Development
8.7 Variations in Sex Development
8.8 Atrazine and Tyrone Hayes
8.9 What about hermaphrodites – and why aren’t they more common?
8.10 Understanding Hermaphroditism
8.11 Wrapping Up: What is Gender?
Chapter 9: Sex Ratios
9.1 Chapter Objectives
9.2 Characterizing populations
9.3 An Introduction to Operational Sex Ratios
9.4 Variety in Operational Sex Ratios
9.5 The puzzle of skewed sex ratios at birth
9.6 The Trivers-Willard hypothesis of sex allocation
9.7 Testing Trivers-Willard in opossums
9.8 Testing Trivers-Willard in red deer
9.9 Testing Trivers-Willard in spider monkeys
9.10 Testing Trivers-Willard in humans
9.11 Beyond Trivers-Willard
9.12 Male bias and extreme sex ratios
9.13 Wrapping Up: Understanding human sex ratios
Chapter 10: Sexual Selection (contributed by Rachel Olzer)
10.1 Chapter Objectives
10.2 What is sexual selection?
10.3 How does sexual selection work?
10.4 Can we see markers of sexual selection in animals?
10.5 Why be choosy about your mate?
10.6 Unconventional ways of finding a mate
10.7 When males and females do not agree
10.8 Post-copulatory sexual selection
10.9 What is the evidence for sexual selection in humans?
10.10 What’s up with the human female orgasm?
10.11 Is the brain another object of sexual desire?
10.12 Understanding human mating through language and culture
10.13 Understanding the naturalistic fallacy
10.14 Wrapping Up: Understanding the silent crickets
Chapter 11: Mating Systems
Chapter 12: Sexual Orientation and the Evolution of Homosexuality
12.1 Chapter Objectives
12.2 What do we mean by “Sexual Orientation?”
12.3 Sexual preference is not binary
12.4 Homosexuality is widespread in nature
12.5 Is sexual orientation genetic?
12.6 Is sexual orientation influenced by the environment?
12.7 Fraternal birth order and the uterine environment
12.8 Why is homosexuality an evolutionary “problem?”
12.9 How did homosexuality evolve?
12.10 Testing some of the hypotheses about the evolution and occurrence of homosexuality
12.11 Understanding homophobia
12.12 Wrapping Up: And Tango Makes Three
12.13 Read More
Chapter 13: Sex Machine: Reproductive Anatomy and Physiology
13.1 Chapter Objectives
13.2 Every body is different.
13.3 Commonalities between male and female reproductive anatomy
13.4 Male reproductive anatomy
13.5 Male reproductive physiology
13.6 Sperm are produced in the testes
13.7 Female reproductive anatomy
13.8 Female reproductive physiology
13.9 Wrapping Up: Revisiting Circumcisions
Chapter 14: Copulation and Fertilization (Baby-making 101)
14.1 Chapter Objectives
14.2 Diversity of sexual intimacy
14.3 Plant Sex
14.4 Animal sex, from fish to birds
14.5 Mammal Sex
14.6 Human procreative copulation
14.7 Human fertilization: from gametes to a zygote
14.9 Fertility Treatments
14.10 Wrapping Up: Returning to Sex Education
Chapter 15: Gestation & Birth
15.1 Chapter Objectives
15.2 The first two weeks
15.3 Gastrulation, neurulation, and beyond
15.5 How are twins made?
15.6 Labor, delivery, and lactation
15.8 Wrapping Up: Revisiting the missing mother case
Chapter 16: Sex & Violence
Chapter 17: The Biology of Love
This chapter is under development!
The Evolution and Biology of Sex by Sehoya Cotner and Deena Wassenberg is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.