Sex Differences

Sexual Reproduction Advantages of Sexual Reproduction Fossil records Genetic Diversity Potential Protections Potential Adaptations Fossil records

Sexual Dimorphism Sexual Dimorphism Parental Investment Competition Humans

Hunter-Gatherer Differences Duties=Abilities Evolved Differences Examples

Genetic Differences 23rd Chromosome Pair Default sex Y Chromosome

Hormonal Differences Androgens Estrogens Testosterone Female Hormones

Hormones Outside of Puberty Estrogen Progesterone Testosterone Sex Drive Castrated Males

Physical Differences Men Women Taller, Stronger Greater Muscle Mass Higher WTH ratio More body hair Thicker, more oily skin Larger Adam’s Apple Higher concentration of red blood cells Women Lower WTH ratio Warmer skin Higher percentage of body fat

Health Differences Men Women More Cardiovascular disease More Lung cancer More chromosomal conditions (X-linked) Women Live longer More Osteoarthritis, Osteoporosis More elastic blood vessels Lower blood pressure

Sensory Differences Men Women More likely to develop hearing impairment More likely to have color-blindness Higher tolerance to pain Women More sensitive sense of smell More sensitive to color differences More pain receptors More sensitive to sound, especially in higher ranges

Brain Differences Men Women Bigger Brains (not heavier, though) Larger left inferior parietal lobes Larger “sexually dimorphic nucleus” in hypothalamus Women Larger Wernicke’s and Broca’s areas Parts of corpus callosum larger Faster blood flow to brains Lose less brain tissue

Cognitive Differences Men Better at 3D mental rotation tasks Better at tasks requiring navigation through unfamiliar terrain Navigate using abstractions (north, south) Better at higher levels of mathematical reasoning Women Better at spatial tasks involving location memory of array of objects Better at identifying/locating specific plants Navigate using landmarks Recover language function better, more quickly after stroke

Social/Emotional Differences Men More SA More ASPxDx Women More depression More anxiety More eating dx Show more activity in the brain when processing emotional events

Behavioral Differences Men More physical aggression More violence More risk-taking behaviors Women More relational aggression (unlike bonobos) More nurturing behaviors

Fears Female Fear vs. Male Reality Males Risk-Taking Female Cautiousness

Reproductive Differences Fertility Start of Puberty Females Fertility Male Fertility World Records

Infidelity Mating Strategy—Mating BEHAVIOR Short Term vs. Long Term True Monogamy Naturalistic Fallacy