Body Size

Pathogen Resistance 

Symmetry

Motor Coordination 

Competition between members of the same sex 

The bigger the display the more competition 

Creates Sexual Dimorphism 

large canines, antlers --> weaponry 

males have a much higher variance in the amount of RS than females. 

Fruit Flies 

Trivers and Anolis lizard 

Traits that allow opposite sex to choose best genes 

Bower Birds

Happens when there is no male investment - competition for investors 

Trivers 

parents invest in offspring but not to much or it will hurt RS of future potential offspring.

Hiwi

Ache

more males than females - stable relationships 

more females than males - unstable marriages 

When females mate with multiple males at a time 

creates sperm competition 

Damselfly Penis

Copulatory Plugs

Penis Barbs 

Rats

sperm bunch together to out swim competitor's sperm. 

Penis/ Teste size and sperm competition

Gordon Galluo

Gorillia

small penis/teste virtually no sperm competition

Chimpanzees

huge penis/teste lots of promiscuity lots of sperm competition. 

Humans 

Large penis, middle testes, shows some promiscuity and sperm competition. 

Gallup - thrusting during sex - semen displacement device 

Polyandry = large testes 

Lecks = small testes 

Runaway effects of Sexual Selection

Mom has sex w/ exaggerated trait 

Sons obtain that trait 

Daughters seek that trait

Exaggerated trait grows. 

boulder 

impressive that both can make it up a hill but better if you can do it with a boulder 

surviving with costly characteristics is better than just surviving alone. 

Secondary Sexual Characteristics are an Honest signal for good genes 

The more ornate the feature, the less parasites, the better the genes. 

nuptial gifts

bower nests

Female Scorpion flies lay more eggs when males bring a bigger gift and have a bigger body size 

Manipulation of tail legnth

Females like longer tails even when the tails were fake 

Growth

Repair and Maintence 

Reproduction 

Fat Storage in: 

thighs

butt

good for infant brain development 

Menstrual Cycle

Increased Musculature

Competitive Mating Displays 

Testosterone drops after fatherhood - redirects energy to investment .

Western societies opt to have fewer children

Focus on quality instead of quanity 

Social and Physical Mobility

may live somewhere you don't know anyone

Limits reproductive success 

unique to humans 

Grandmother Hypothesis

women gain RS later in life by helping their daughter's children grow 

loots at morphology

Pros: observable characteristics 

Cons: Convergent Evolution - fins in whales and sharks does not mean genetic relationship 

Looks at divergence of last common ancestor

Pros: more objective

Cons: have to guess on time and sequence of splits. 

Dermatoglyphics 

Stereoscopic Vision

Opposable Thumbs

Reduces Olfaction 

Allopatrics

50 mya after Africa and South America separated. 

Separates Humans from all other primates

Humans moved out to grasslands 

Increased Stamina, less speed 

PROBLEM: relies on the need to search for meat, bipedalism happens before meat eating. 

Frees hands to transportthings 

Bipedalisn in late Miocene:

climate change

food becomes scarce 

Humans travel large distances to feed large groups 

6-4 mya

E. Africa

Quadrupedal in Trees, Bipedal on Ground 

Small Canines 

Woodland Omnivore 

Opposable Big Toe

4-1.2 mya

E. Africa, S. Africa

Teresstial biped 

Large Teeth

Africa, Asia, Europe

Large Brain

Reduced teeth, jaws

Extensive tool use 

Tool Use

Hunting

Cognitive Maps

Fission-Fusion Social System

Medicinal Plant Use :

In Chimps

sticks, rocks, leaves, stones 

crack nuts w/ rocks, make spears 

Work together to kill/eat bush babies 

meat sharing 

Ability to remember where goods are located, bring tools to help them. 

Get very worked up and then apologize for it through grooming 

Matriarchal 

very little sexual dimorphism 

Constant Sex 

Rapidly Growing Brains 

Neocortex - related to social groups 

(Like elephants and cetaceans) 

Our brain should be 264g instead it is 1,300! (Allometry)

Something pushed for the large brains in evolution 

Energetically Expensive 

correlates with adding meat to the diet 

tradeoff - smaller gut 

Allowed for larger brains 

cut marsk on animal bones 

dental adaptations

Brain uses 20% of energy

need meat to support it 

Large brains small pelvic opeing

Babies born 12 months early, should be 21 months old. 

Caused more parental care

less dimorphism

Concealed Ovultation

Theories: 

Daddy at Home Theory - Kept men close by becuase they never know when females were ferilte 

ensure male attention 

Sex for food theories - prevents men from withholding resouces when female is not fertile (Ache) 

Anticontraceptive Theroy - prevents females from being able to avoid getting pregnant  WEAK

EPC Theory - allows females to sneak EPC's with better genes during peak fertility. 

Stereoscopic vision

Manual Dexterity

GOOD IN THEORY but other quadrupeds have these things and not huge brain. 

maybe smart because they had to deal w/ place adaptations? 

not a good theory because other things have to do this w/o big brains. 

Homo Erectus 

Largest period of rapid brain growth 

but no significant tool change 

Handednes - not seen in other population 

Left brain - science and math

Right Brain - Creativity 

Social Intelligence of group 

Have to keep track of thing you are observing even when you aren't directly interacting with that person. 

Like Corrupt Politicians. 

Ability to understand how other people feel

Autistic Kids don't have this 

Zero Order - does not know it exists, like rock

1st Order - self awareness 

2nd Order - Theory of Mind, aware that you are aware 

 neocortex, most amount of differentiation 

important for social structure 

Females Choose things they want

Like Hadza and deep voices 

Jazz Musicians 

Huge Stone Tool Display 

Language Acquisition - highly specialized 

Broca's Area - speech

Wernicke's Area - comprehension 

Self morph experiments

males preferred much more the ones that looked like them 

females didn't have a preference 

maternal grandmother > maternal grandfather > paternal grandmother > paternal grandfather 

people leave more to kin than non-relatives 

leave more to close than distant kin

leave more to offspring than siblings

wealthy leave more to son

poor leave more to daughters 

Maternal-fetal Conflict

Fetuses want to take more than mother wants to give 

Threshold different for mother and child 

1st few weeks maintained by mom

after few weeks fetus takes over Progesterone levels

HCG

Human Chronic Gonadotrophin

Produced by fetus later in pregnanxt 

stimulates release of progesterone 

helps to maintain pregnancy 

Fetus wants to bring all blood to it

mother develops spiral arteries to combat that 

leads to High Blood pressure and varicose veins 

Maternally active genes

"easy" baby 

poor suckling

sleep a lot

Paternally Active genes 

extract more resources from mother

prolonges suckling

highly active 

inherent wickedness 

Applied sociobiology  to violence

looked at it from an evolutionary prospective 

Common in animals

usually males do the killing

Jacanas: 

females destroy eggs and lay her eggs in nest 

By mothers:

decreased w/ age of the mother 

decreases as child get older, especially after 1st year of life. 

Tokipie

and 

Yanomamo

usually also commit suicide 

done in a quicker, more painless way 

Males divorce at older age, seek younger women 

upset at sexual infidelity 

Females divorce at younger age, seek men with more resources

upset at emotional infidelity 

Kung San!

Ache

Mild polygyny 

Men hunt and offer meat to women for sex 

usually risky

requires cooperation and skill

usually not done by females because of babies 

heavy investment by both partners 

prolonged courship

brief encounter

one-night stand 

EPCs

WHR

SHR

0.7 is best 

smaller preferred but not evolutionary significant

Women with WHR closer to 0.7 have more sex

Men with SHR closer to 1 have more sex  

Females need status and men who can make money 

Men don't care as much about status, more about looks 

Men create this smell

females usually hate it except during ovulation 

female vaginal secretions

males lose ability to decide if female in pretty or ugly 

Romantic Love

Kiss transfers testosterone to females 

Sex drive hormone --> testosterone

Romantic Love hormone --> dopamine 

look more at attractive faces than not

enstilled preference for good genes 

Pathogen Removal - not relavent

Signal of Fertility - not fertile 

Side effect of big endometrial lining. 

Sperm only given to women for reproduction

Men drink it to fight well in battles 

Bonobos 

Rams

Black Swans

Lesbian Gulls 

possible x-linked genes 

sex antagonistic gene? (benefits females not males?) 

Maternal Stress hypothesis 

Additive effect of an older brother 

Males: spatial rotation 

Females: verbal and tactile 

Transsexuals: cross sex patterns right after hormone treatments 

Gay men: perform more like females 

Heterosexual - same sex smells processed in olfactory bulb, opposite sex smells analyzed in sexual area of brain. 

Homosexual - same sex smells processed in sexual area of brain, opposite sex smells processed in olfactory area. 

Seeking

Rage

Fear

Panic

Plat

Lust 

Care

interest, frustration, craving. Related to OCD

anger, irritability, contempt. Related to aggression

anxiety, worry, trauma. Related to phobias PTSD

sadness, guilt/shame. Depression 

Joy ad glee. Mania, ADHD

Eroticism. Fetishes 

Nuturance, dependency disorders 

a.     fitness enhancing behaviors/ traits in past and present

                                               i.     theory of mind, reciprocal altruism, incest avoidance etc.

                                               i.     deleterious consequences in ancestral environment

                                              ii.     reduces fitness in modern times

                                            iii.     caused by malfunctions of otherwise adaptive mechanisms, mutation not yet eliminated by NS

1.     autism, PKU, incest

a.     would have been reduced fitness in the past but became tolerated/desirable in modern times

                                               i.     adoption, philanthropy, fidelity, voluntary reduction in family size

2.       Pseudopathology

a.     provide a benefit in our ancestral past

b.     NOW DECREASES FITNESS

                                               i.     Morbid jealousy, Preferences for food high in sugar and fat, psychopathology

                                                                                                     i.     A build up of these  hormones/fatty acids causes circulatory and heart problems, reduces immune function – is deadly.

b.     Maladaptive for modern scenarios when we experience high levels of stress (road rage, politics)

a.     Major Depressive Disorder

                                               i.     Reacts to a catastrophic event (death of a loved one)

b.     Endogenous

                                               i.     Major depression out of the blue

                                              ii.     Lasts longer

c.      Bipolar Depresstion

                                               i.     Deep depression and intense mania

1.     Leads to creative people : writers, artists

d.     Attachment Disorder

                                               i.     When individuals are removed from mothers to early

                                              ii.     Not able to register emotions ,

                                            iii.     Have problems with relationships, sadness and depression

e.     Post-Partum Depression

                                               i.     A way to solicit help/investment from father/relatives

                                              ii.     Strategy to cease investment

1.     Indicates the child is not viable

2.     Hostile environment

3.     Lack of paternal investment

4.     Too costly in terms of RS

                                            iii.     Studies show that lack of support in the 3^rd trimester is a strong predictor of PPD

a.     Ancient Origins, adaptive?

                                               i.     “Central Paradox of Schizophrenia” – reduces RS

                                              ii.     better able to resist shock of wound/stress

                                            iii.     asymptomatic heterozygotes

1.     able to exploit original and creative niches w/o the bad side effects.

                                            iv.     Kin are highly creative and achieve higher academic success

                                              v.     SIMILAR TO SICKLE CELL ANEMIA 

a.     Cliff Edge effect

                                               i.     Array of mutations of several genes

1.     Each may convey advantages but when presented all in one person the brain is hopelessly distorted 

a.     The human brain – organ that links into wider social networks to extract resources for the individual and flourish. 

                                               i.     Weak gene-culture interaction

                                              ii.     Focuses on variability of cultural practices and behavior

Fad, like silly bands 

Problems with memetics

a.     Analogy with DNA isn’t perfect

b.     CHANGED IN MEMES ARE GOAL DIRECTED

                                               i.     Culture is an adaptation to solve problems in rapidly changing environments.

                                               i.     Maladaptive cultural traits

1.     May accept beliefs that reduce fitness

Cults that preach abstinence GO EXTINCT 

                                               i.     Culture is the elastic leach that can apply force and drag genetic change along

                                               i.     Lactose intolerance

Bowers 

Jazz

Hand Axes 

a.     Moral truths are inherent facts of human nature

b.     Predicted Kin Selection and paternity uncertainty as reason for males to value chastity in women. 

a.     People need to chose lesser of 2 evils

                                               i.     Save greater # of individuals or save kin and family

                                              ii.     Psychopaths sacrificed

b.     Results were independent of religion/culture –

                                               i.     SUPPER FOR A UNIVERSAL EVOLVED MORAL RESPONSE

a.     Preconventional morality

                                               i.     What’s in it for me?

1.     Obey authority/avoid punishment

2.     Self interest, return favors, get even, simple exchanges

b.     Conventional morality

1.     Conforming to expectations, maintain reputation, car for others, loyalty and gratitude

2.     Maintaining social systems, obeying social laws, contribution to moral order in society

c.      Post-conventional morality

1.     Fulfilling social obligations, concern for the welfare of all

2.     Respect for equality of human rights, following universal principles of justice

d.     People rarely reach staged 5 and 6 but can move up and down between levels

Eugenics

Not like social darwinism because it is political 

Franz Boa's student 

said to have found a Utopian society in Samona 

was duped 

look hard enough and you can find anything.