Natural selection and motivation
Polygyny-(harem)
one male mates with many females
Rationale for sexual reproduction
pass on a combination of genetic material to offspring, resulting in increased genetic diversity. Results in a scramble of genes in the population which aids in evolution and protection against disease.
Evolutionary explanations of altruism
pass on genes, genetic self-interest, two main explanations: kin selection, reciprocity In social psychology, reciprocity is a social norm of responding to a positive action with another positive action, rewarding kind actions. allows for members of the same specie to pass on their genetic make up, even if it isn't that actual animal bur rather its close relative. Basically to improve chances of survival of their type. Altruism may be linked to a form of expressing genetic self-interest by helping others, in a "i scratch your back you scratch mine" type relationship
inclusive fitness
Inclusive fitness - Assistance of kin's reproduction - Leads to cooperative behavior - "Altruism" = genetic self-interest (?) Cooperative Predation Cooperative Mating Cooperative Defense Cooperative Parenting: Family Life in Monkeys •Inclusive fitness: I assist my relatives to forward our genes onto the next generation
Galton's anthopometry
Darwin's cousin Originated anthropometry - measurement of human characteristics; about 18,000 people were measured in the Galton Laboratory from 1880-1900: - Physical abilities like height, girth, fingerprints, head size - Mental abilities like visual and auditory acuity and reaction times, color vision, touch discrimination Galton believed that sensory abilities predicted intellectual abilities - his student Karl Pearson developed a way to measure their correlation •Most humans' traits fit a normal distribution •Believed most traits were hereditary and not based upon experience •Study identical and fraternal twins (intelligence and personality
Herrnstein-Murray "dysgenics" argument
The Bell Curve (1994) - Richard J. Herrnstein and Charles Murray. Assertions: - IQ is substantially the result of heredity and not environment - IQ explains success in life far more than social class - IQ is not easily changeable by intervention - The emergence of a "cognitive elite" is unstoppable. - Since low-IQ people have more children, there is ongoing dysgenesis, in which the elite must shrink as a proportion of the population. - The ultimate effect of dysgenesis is more poverty, drugs, illness, war
Out-breeding drive and MHC findings
"reverse imprinting": a hereditary predisposition to avoid kin in mate selection ; major histocompatibility complex influences what attracts us, since major histocompatibility complex regulates immune system (i.e. whichever body odor is most attractive to us also means good immune system compatibility with outs, which means more attractiveness to us) MHC molecules enable immune system surveillance of the population of protein molecules in a host cell, and greater MHC diversity permits greater diversity of antigen presentation mating with unrelated partners maximize different allele mixing and creating new allele combinations;
Natural selection
Because resources are limited, organisms must necessarily battle for survival. Those organisms that possess favorable characteristics in that environment will reproduce more; i.e., they are "fitter." Because of this differential reproduction, characteristics that are favorable in that environment will proliferate, whereas those that are unfavorable will decrease. Reliable trends in natural selection constitute evolution by natural selection.
Sexual dimorphism
Differences in physical characteristics between males and females of the same species. Females tend to be bigger except in species with proportionally large brains. obvious differences between males and females of any given species (i.e. females are usually bigger than males, except in species with proportionally large brains)
Cryptic ovulation w/rationales
Estrus (recurring period of sexual receptivity and fertility in many female mammals; heat.) replaced by menstruation Concealed ovulation or hidden estrus in a species is the lack of any perceptible change in an adult female (for instance, a change in appearance or scent) when she is "in heat" and near ovulation. Unlike other mammals, which go into "heat" during fertile periods, women can be up for sex any time of the month. Evolutionary theorists have tried at several explanations for the loss of this estrus cycle in humans, one of the most common being that humans lost the "heat" phase to conceal ovulation Perennial receptivity: partial release from hormonal control Hypotheses: (Pair-bonding vs. sneaky-f***ing)
Identical vs. fraternal twins, and purpose of twin studies
First posited that most human traits fit a normal distribution. Published Hereditary Genius (1869) - Studied 1000 members of 300 families of "eminence," and concluded that "eminence" runs in families Eminence-recognized superiority - He announced his view that most human traits were much more the result of heredity than environment - Coined the terms "nature and nurture" to describe the twin influences on traits; her popularized the nature/nurture debate. - Proposed the study of identical vs. fraternal twins to isolate the effect of heredity, and reported a study of 80-100 twin pairs. This twin method became key early method of studying intelligence and personality traits Coined the term eugenics in 1901, stating: "The possibility of improving a race or a nation depends on the power of increasing the productivity of the best stock."
What Darwin learned from Malthus and Lyell
From this, Lyell inferred that Earth must be far older than most people believed. Thomas Malthus (1766-1834) was an English economist. He wrote an essay titled On Population. In the essay, Malthus argued that human populations grow faster than the resources they depend on. Malthus wrote "Essay on the Principle of Population" (1798), which Darwin read and was inspired by. The central theme of Malthus' work was that population growth would always overpower food supply growth, creating perpetual states of hunger, disease, and struggle. Allowed Darwin to understand geology. First, he asked himself: If the Earth could change over time, might life change as well? Second, h realized that it would have taken many years for life to change the way he suggested. This would mean the Earth was extremely old.
Requirements for natural selection:Inheritance mechanism
Inheritance. Some traits are consistently passed on from parent to offspring.
Kin selection
Kin selection is the evolutionary strategy that favours the reproductive success of an organism's relatives, even at a cost to the organism's own survival and reproduction. Kin altruism is altruistic behaviour whose evolution is driven by kin selection. Kin selection is a type of natural selection where individuals will sacrifice their own lives in an effort to save closely related organisms; therefore, ensuring the survival of genes that they both share.
Requirements for natural selection: Variability
Organisms (within populations) exhibit individual variation in appearance and behavior.
Requirements for natural selection: Selection pressures
Selective pressures drive natural selection. Some members of the population will not survive and reproduce and, thus, will not pass on their genes into the next generation.
Sexual orientation and possible determinants
Sexual Orientation as a Correlated Variation of Prenatal Androgens Determined by a correlated variation of prenatal androgens (i.e. female homosexuality caused by exposure to higher-than-usual levels of prenatal androgens) (i.e. male homosexuality caused by region Xq28 that promotes fertility in females)
Origins and purpose of eugenics
Sir Francis Galton first coined the term "eugenics" in 1883. Put simply, eugenics means "well-born." Initially Galton focused on positive eugenics, encouraging healthy, capable people of above-average intelligence to bear more children, with the idea of building an "improved" human race. Some followers of Galton combined his emphasis on ancestral traits with Gregor Mendel's research on patterns of inheritance, in an attempt to explain the generational transmission of genetic traits in human beings.
Spectrum vs. Dual-attraction models of sexual orientation
Straight Bisexual Gay --------------------------------------------------------- Spectrum Androphilia Gynecophilia Biphilia Aphilia Dual Attraction
Identical vs. Fraternal Twins
Twins can be either monozygotic ("identical"), meaning that they develop from one zygote, which splits and forms two embryos, or dizygotic ("fraternal"), meaning that they develop from two different eggs. In fraternal twins, each twin is fertilized by its own sperm cell.
Taxes w/ examples
When you leave a plant in the window during the summer, it will grow towards the window (i.e. towards the source of light). This is called positive phototaxis because it is a directional movement towards the light (rather than a nondirectional or random movement). phototaxis: movement of a cell or organism toward or away from a light stimulus Chemotaxis: Movement that is directed by chemical gradients, such as nutrients or toxins. (seen in some bacteria) Geotaxis: A tendency to orient in reference to gravity either toward the ground (positive geotaxis) or away from the ground (negative geotaxis)
Sexual selection
a type of natural selection in which members of one sex compete for reproductive access to members of the other sex
Incitement and "female choice" in mating
an act of urging on or spurring on or rousing to action or instigating (i.e. female monkey pushing her tail against a male monkey's when she is in heat)
Cryptic female choice
biochemical processes occuring in the ovum, and the ovum looks for a specific chemical code to let a sperm in (infertility is caused when the ovum is too specific to let any sperm in, and therefore never fertilizes)
Helen Fisher's phases of love: lust
characterized by love-seeking, driven mostly by testosterone and estrogen
Helen Fisher's phases of love: attachment
developing a bond; less attraction and lust; driven mostly by oxytocin and vasopressin
Male displays resulting from sexual selection
display of strength and personal fitness through violence or display of color such as in birds.
"Gaydar" and sexual-orientation stereotypes
gay people are flamboyant, showy, and feminine; not always true (i.e. gaydar test with british star)
Mating criteria
female selection: height, muscles, angular appearance, predictability, gifts, caring during illness, intelligence, sense of humor male selection: youth, youthful features, symmetry, hourglass figure both sexes like faces similar to their own
Fixed action patterns & releasing stimuli
fixed action patterns: a genetically programmed, virtually unchangeable behavioral sequence performed in response to a certain stimulus releasing stimulus sign stimuli; elicits a fixed action pattern in the same species the stimulus causing a fixed action pattern Fixed action patterns, or similar behaviour sequences, are produced by a neural network known as the innate releasing mechanism in response to an external sensory stimulus known as a sign stimulus or releaser
Tryon behavior-genetics study
generational rat study; bred "dull" and "smart" rats based on how many errors they made in a maze to get to the cheese, and found that intelligence may have something to do with inheritance
monogamy
having one partner for life (i.e. husband and wife) •Monogamy- largest mating systems
Evidence on human infant imprinting
human mother-infant bonds; baby learns who mama is early in life, and never questions it example: learning a second language as a toddler The best-known form of imprinting is filial imprinting, in which a young animal acquires several of its behavioral characteristics from its parent. It is most obvious in nidifugous birds, which imprint on their parents and then follow them around in mammals it is rarer. Primates are born much more helpless and "incomplete" with a very immature brain. The mother is the all important provider and protector, care-giver and companion. The bonding and growing take place over longer periods of time.
Imprinting & critical (sensitive) periods
imprinting: latching onto a stimulus during a critical period (i.e. olfactory: babies learn mama's smell and associate mama with that smell) critical period: period directly after birth when many life reflexes and patterns are learned (i.e. learning a birdsong: a baby bird is in record mode until it hears its father's song, after which record mode shuts off and the bird masters the song)
Personal vs. inclusive fitness
inclusive fitness: the fitness of an individual organism as measured in terms of the survival and reproductive success of its kin, each relative being valued according to the probability of shared genetic information, an offspring or sibling having a value of 50 percent and a cousin 25 percent.
Vestigial structures and importance to Darwin
living organisms, including man, contain organs that were once functional in our evolutionary past, but that are now useless or have reduced function (tail bone, wisdom teeth)
Helen Fisher's phases of love: attraction
love-struck, loss of sleep/appetite, driven mostly by dopamine, norepinephrine, epinephrine
Corvid intelligence w/examples
most intelligent birds (i.e. crows, ravens, magpies, etc...) ; demonstrate self-awareness, and intelligence in feeding skills, memorization, use of tools, and group behavior (i.e. inventing games
Promiscuity
no rules / f bitches get money (perhaps gay or straight)
Polygamy
one animal has many mates Although polygamy also involves mating with multiple partners, it often refers to cases in which individuals form relatively stable associations with two or more mates. Most such species exhibit polygyny, in which males have multiple partners.
Polyandry
one female with many males (common amongst insects)
Mate guarding
restrictions on female behavior, jealousy and violence, female sexual mutilation; any form of behavior used to keep your mate from being in contact with any other potential mate (i.e. jealous boyfriends)
Incest w/costs
sexual intercourse between persons too closely related to marry; Genetic cost of incest usually overstated; odds of birth defect if one parent has it are: ~3% if parents are unrelated, ~4% if parents are first cousins, ~10% if parents are siblings
Kinsey survey
sexual orientation survey that proved that orientation is not clear cut and is a moving target devised an experiment with 7 equal intervals that measured your sexuality.
Taxis
taxis), meaning 'arrangement') is the movement of an organism in response to a stimulus such as light or the presence of food. Taxes are innate behavioural responses. Taxis (movement toward or against a simple stimulus) Reflex
Advantage of sexual reproduction
those with good genes get to pass them on Gene variety; stronger genes ; increased disease resistance. pathogen protection
"Correlated variations" with sexual orientation (finger length etc.)
traits exhibited often by homosexual people that leads people to believe that trait is linked with homosexuality (i.e. finger length differences, otoacoustic emissions) in men, if pointer is shorter than ring, and in female if it is longer (straight) In women with a homosexual orientation, right-hand 2D:4D finger lengths are lower Several studies have suggested a link between sexual orientation and digit ratio, with men who have longer index fingers more likely to say they are attracted to other men. The inverse has been suggested for gay women: while women typically have a ring finger and index finger of the same length, those who identify as lesbians are more likely to have shorter index fingers, which is typical for heterosexual men.
Incitement & flirting
when one person is attracted to another, they will urge a certain kind of (sexual) behavior by flirting with them
Evolutionary explanation of sex roles
women have little chance to pass on their genes, so they have to be selective about who they mate with; men are the complete opposite
College "gender gap" and hookup culture
• Average age of marriage has gone from ~ 20 in 1970 to ~26 by 2003. Therefore, most marriages are occurring many years after the end of college, and not right after college. • In 2006, only 14% of people who are married or in a relationship met their partners at school or college, down from 23% in 1992. • "Credential inflation" has increased educational requirements for many jobs, and has prolonged educational years for many. • Feminism has influenced women to initiate sexual contact more, without as much shame or guilt. • More women than men report "hoping" that a hookup will lead to further contact and possibly a relationship. •In a recent study of 4,000 college students: o 76% reported engaging in hookups. o by senior year, students reported having an average of 6.9 hookups and 4.4 traditional dates • Women are now > 60% of college enrollments, from a ratio of 1:2 females to males in 1960. F: M ratio projected to be 65:35 by 2025. This is accompanied by great increase in F college faculty. Some observers find a "feminization" of college curricula, widespread teaching of masculinity as "toxic," and males as hapless representatives of "patriarchy
personal fitness
• Personal fitness prowess: direct reproductive prowess
Neoteny
•Baby chimps look more like humans than adults •Humans have an extremely slow maturation rate •Humans hang on to youthful features •Chimps spins being to bend, and snouts begin to protrude •Neoteny: holding onto the old
Vervet monkeys and calls
•Species closet to having a language •Different calls are used to alter other monkeys •Shows they have some type of useful language •Female vervet take care of the young, when two juveniles get into a fight, causes mothers to stare at each other