Anthro 38 HBE

Know what anisogamy is, and that it probably evolved by disruptive selection. You don't need to know WHY sexual reproduction evolved, but you should know some benefits of sexual reproduction.

Anisogamy: evolution of sex; 2 or more morphologies WHY SEX: -lottery: variable offspring survive in changing environment -spatial heterogeneity (disproved) -red queen: host pathogen co-evolution (immunological evolution) -DNA repair hypothesis (sex cells tend not to get damaged) *variability is good in terms of genes*

How do apes differ from monkeys in their skeletal morphology?

Apes: -no tails -have forelimb suspension -have short, stiff lower backs ---enable them to spend some time as a biped -Mobile joints ---flexible wrists and shoulders -Long arms and fingers ---touch the ground ---walk on knuckles

Do modern-day foragers accurately represent humans in the EEA? Support your argument.

Argument 1: have had millions of years to develop so no Argument 2: likely closest group to those in EEA

What came first in the human lineage, bipedalism or brain expansion?

Bipedalism a) Australopithecus was bipedal but still had a brain that more resembled a primate, brain expansion can be seen later when b) Homo-habilis emerged with a larger cranium for a larger brain

Be able to calculate simple demographic measures (cumulative and age-specific survival, fertility and mortality). Why are fertility and mortality correlated?

By principle, expending greater effort in reproduction (resulting in greater fertility) will imply less energy expended on maintenance (higher mortality). Therefore, this shows that generally greater fertility means higher mortality, and lower fertility means lower mortality rates.

How do chimpanzee and human development and life history trajectories differ?

Chimps: -smaller, weigh less in gestation -grow faster from 5-10, stop @ 13 and reproduce -30-60 y lifespan Humans: -earlier weaning -still growing @ 13(reproduction @ 19) -max 120 y lifespan

What is a conditional behavioral strategy? Provide two examples from class.

Conditional strategy - some strategies may be more ideal depending on environment --Fertility rates in different hunter-gatherer societies (!Kung ~5, Pume ~7, Tsimane ~9)... fertility rates change by modernization --Height (growth rates) in different social classes of London boys - factory workers<laborers<public school<upper class

Be able to distinguish between intra-sexual and inter-sexual selection. On which sex does sexual selection mainly act in mammalian mating systems?

*Intrasexual selection is selection within the same sex. For example, some male animals compete against one another, physically, for access to females. So something like big antlers, huge sharp Ex: sperm production, size, males fights * Intersexual selection is selection between the two sexes. For example, the bright plumage of a male peacock does not help it physically overcome rival males. But female peacocks tend to prefer male peacocks with bright plumage: a brightly colored male peacock has a selective advantage Ex: peacock, face fat

How do convergent traits (analogies) pose challenges in phylogenetic reconstruction? Provide examples.

Convergent traits pose a challenge to phylogenetic reconstruction because they mimic homologies. An example of a convergent trait is wings evolving in birds, bugs, and mammals independently.

Describe the two main components of the obstetric dilemma. What other costs are associated with bipedalism?

-Humans have large brains (Infant cranial/Pelvic ratio especially large in humans) -Humans are bipedal (Pelvic size/shape/orientation) ---Birth is risky because of the small human pelvis ---the infant needs to twist around in order to get various parts of it's body though the mother's pelvis ---infants are born facing away from the mother: necessity for midwifery (more co-operation) -pregnancy is hard (spine) -human babies not fully developed (only 25% of brain)

What is group selection? Explain why the individual can (generally) be thought of as the unit of selection.

-Natural selection acting at the level of the group NOT the individual - kin selection -one gene's mutation -Natural selection acts at the level of the individual, not the species because if it did then we would be LOSING SPECIES a lot more often

What contributions did Linnaeus make?

-The father of taxonomy -published "Systema Naturae" -Systematics (grouping things) -Taxonomy (naming things)

Kramer-What contribution do these papers make to understanding human foragers in the EEA?

-analyzed Pume and other SA group -small scale societies do not have decreasing birth and fertility rates **birth rate increasing, mortality drop-not following trends that EEA would predict**

What is the human feeding niche (in a foraging context)? How does it contribute to the division of labor and evolution of long lifespans in humans?

-consume high energy food (hard to get) -humans divide up roles (helps nutrition) -train as infants/children -more nutrition=longer lifetime

What are some common characteristics of foraging societies (in terms of demographics, ecology, behavior, social organization)? Have your beliefs and opinions about foragers changed since the beginning of the course?

-environmental knowledge -traditional medicine such as herb use (tobacco -used for swelling and cuts) -clearly defined gender roles -home-made tools -egalitarianism -subsistence contingent on the environment -high infant mortality because of the multitude of infectious diseases/accidents -division of labor (male hunting, female infant care -food sharing (variation in hunting luck leads to sharing, survive illness more, boost prestige)

Is midwifery a human universal? Is it unique to humans?

-human emerges facing wrong way-NEED help -most societies woman don't alone -monkey had midwife of worts (research)

Understand the nature of correlated life history traits. What kind of life history strategy do non-human primates have? What kind of life history strategy do humans have?

-lx=probability of surviving until age x -mx=fertility at age x -qx=probability of dying during age interval x -sx=probability of surviving during age interval x How measures are computed: -lx=the number of individuals alive at age x divided by the number of individuals born -mx=the number of offspring born during interval x divided by the number of individuals who started interval x -qx=the number of individuals who die during interval x divided by the number of individuals who started interval x -sx=the number of individuals who survive interval x divided by the number of individuals who started interval x CHIMPS v. HUMANS: -Same gestation length (about 9 months) -Humans Grow slower for the first 5 years of life -Chimpanzees stop growing by about age 13 and begin reproducing (versus cessation of growth and commencement of reproduction around age 19 among hunter-gatherers) -Humans have longer growth and thus a larger body size -Human hunter gatherers have a life span about 3 times longer than chimpanzees (40 more years on average)

What are two major implications of the obstetric dilemma (major adjustments to the human life course)?

-need help with birth -brains underdeveloped-more care for child (dependent) ???? yes

What do you think about the Grandmother Hypothesis? Is it sufficient to explain the evolution of menopause in human females? If so, then why don't men show a comparable stage of reproductive senescence? How have your grandparents helped you throughout your life?

-post-reproductive females have more energy to spare to subsidize motherhood -Male food production peaks later/is harder to learn --different life-history cycles influenced by the 'need' to subsidize motherhood --male investment in offspring (provisioning) is still possible later in life? -grandparents share some genes with you??

What is the EEA, and why is it extremely difficult to reconstruct? What is the difference between Pleistocene foragers and Holocene forager?

-prime 200,000 ya -there is a time when we became humans, a time in which our brains were growing and we were big game hunters. This period of time is mythologized as a time when we were "in touch" with our environment. This is when modern human behavior was evolving around 200 kya. -Marlow paper: Pleistocene (2 million ya-12,000 ya) --homo erectus to modern -hunting big game Holocene: agriculture/dogs

What is the functional significance of the flaring bipedal pelvic bones?

-serve the same purpose as the sagittal crest (stronger muscles) -create more surface area to attach muscles to keep the biped balanced, upright, and able to move

Marlow-What contribution do these papers make to understanding human foragers in the EEA?

-using forager data to "explore relationships between habitat and social organization and compare humans to other species" -main obstacle is technology **society has developed, tehcnology-society different**

When do evidence for modern human anatomy and behavior, respectively, appear in the fossil record?

1) 200,000ya anatomy 2) 60,000ya leave Africa 3) 40,000ya Europe/Asia 4) 18,000ya BEHAVIOR in Americas split from chimps 7 mil 5 mil bipedalism

How did H. ergaster/erectus differ from early Homo (H. habilis/rudolfensis)?

1) H. habilis earlier than H. ergaster 2) Homo ergaster/erectus bigger, heavier than H. habilis 3) reduced seuxal dimorphism in H. ergaster compared to H. habilis 4) H.ergaster has body proportions of modern human 5) H. ergaster ate meat

How do human and non-human primates distinguish kin from non-kin, and why is this important?

1) Location 2) Familiarity 3) Phenotype It is important to both groups to ensure that incest is avoided and individuals are able to spread their genes most effectively; avoid sharing genes with those who already have very similar genetic make up.

What are some examples of trade-offs in reproduction? How do they differ between males and females?

1) Mating versus parenting 2) Quantity vs quality of offspring 3) Current versus future production 4) Parent versus offspring --They differ between males and females in that males remain invested in reproduction later in life than females ****?!?!?

What are three components of the "human environment?"

1) Physical (Climate, topography, geology, hydrology, energy, raw materials) 2) Biotic/Local Ecology (food, pathogens, predators, symbionts, raw materials) 3) Cultural/Demographic (social-religious-economic-political, population structure and dynamics, technology and material culture)

According to Kaplan et al, what are four distinguishing characteristics of the human life history? How are human infancy and childhood unique among the primates?

1) an exceptionally long lifespan 2) an extended period of juvenile dependence 3) support of reproduction by older post-reproductive individuals 4) male support of reproduction through the provisioning of females and their offspring Human infancy: higher rate of survival, slower growth rate between 5-10, early high weight gain, longer span, brain growth stages..... (more but necessary)

What traits distinguish the class Mammalia?

1) forelimb structure 2) fur 3) mammary glands

What traits characterize the primate order?

1) grasping hands and (usually feet) 2) nails instead of claws 3) Forward-facing eyes encased in bone --must be FULLY encased in bone 4) Stereoscopic vision --overlapping and forward facing 5) Reduced olfaction (smell) 6) Larger brains --general enlargement in both shape and size --shape shifted from flat to round

According to Cartwright, what are five key features of human evolution? Why might these traits have been favored by natural selection?

1) increased body size (helps fend off predators) 2) brain size (allows for more advanced tool development) 3) sexual dimorphism (male parenting increased chance of survival for infants) 4) altriciality-baby gets fed (allows for increased brain size) 5) female exogamy (dispersal) (add to gene pool..increased genetic variation)

What methods are used to test hypotheses in "Darwinian Psychology?" Know the difference between primary and secondary data analysis, and know the strengths and weaknesses of each method.

1)Primary Data Collection 2) Cross-Cultural Analysis 3) Phylogenetic Analysis Primary data analysis: consists of the collection of specific information for the purpose of their own study (researcher themselves) -limited in scale -time and $ Secondary data analysis: is conducted in references to databases and research conducted by past experimenters.(ex.Census) -larger time periods -inexpensive -lots of useless info / not what you need

Be able to distinguish between a biped and a quadruped using a) a pelvis b) a skull and c) a foot.

Pelvis: -short and stout -abductor mechanism (thing that holds up hips) Skull: -little hole so head is upright from spine Foot: -platform, not grasping (smaller toes -arch Knees: joints enlarged

How does the ecological challenge hypothesis attempt to explain the evolution of primate intelligence? How have Kaplan and colleagues expanded this hypothesis to explain the evolution of human intelligence?

Primate intelligence evolved because primates occupy a relatively complex feeding niche -fruits have higher caloric value per unit mass and require more -complex cognition to obtain extractive foraging (primates obtain food from sources that other mammals don't use) -food helped brain grow CAUSED: intelligence, long developmental period (grow brain), 3 generational resource system, long adult life

What are Tinbergen's questions?

Proximate Causation: (MDEF) 1) What are the mechanisms that cause the behavior? (Proximate mechanism) --at the individual level --something close to the behavior that is driving it in the most simple form 2) How does the behavior develop? (Development) --individual level --both social and biological Ultimate causation: 3) How has the behavior evolved? (Phylogeny) --in comparison to other species --Is this trait unique or different from relatives? 4) What is the function of the behavior? (Function)

Why is sexual dimorphism (in body size) huge in gorillas but small in humans?

Sexual dimorphism is very apparent in gorillas but not in humans because of the difference in mating systems. -gorillas practice polygamy (1 male, multiple females) -need large bodies to fight -females choose bog, strong guy -humans invest in children, more cooperation

What is a species? How do species (typically) form?

Species: organisms that interbreed so they are connected through gene flow, and can produce fertile offspring -all living humans are one species New species? -isolation & no gene flow

Is sperm competition a form of intra-sexual or inter-sexual selection?

Sperm competition is a form of intra-sexual selection because it takes place between competing males, this is an alternative to fighting in order to gain mating privileges. CHIMPS

Explain why apes flourished in the early Miocene.

The Miocene was a warm and wet climate that provided plenty of food sources and was the perfect environment for apes to evolve into many species

Provide examples of energetic trade-offs in humans (between growth/maintenance and maintenance/reproduction and growth/reproduction).

They have developed in humans life history to the following features: 1) At youth, willing to trade potential energy expended in reproduction to energy expended in growth 2) At maturity, willing to trade potential energy expended in reproduction to energy expended in maintenance --Intergenerational wealth flows could only stand if children are assets to their parents, i.e. possess enough fitness to produce fertile offspring and sustain it. Therefore, this justifies the natural selection pressure to expend more energy on reproduction and support of the growth of the child for a relatively long time, in order to maintain the intergenerational wealth flow

How are phylogenies constructed?

Use genetics to reconstruct phylogenies -genetic distance: measures all over genetic similarity -more nucleotide differences=more difference -similar genetic makeup implies recency of common ancestry

Why are WEIRD humans a poor sample in which to study the evolution of human behavior?

W(esternized) E(ductated) I(ndustrialized)R(ich)D(emoratic) -Most humans are not WEIRD -Humans did not evolve while in this WEIRD state

Can demographic characteristics be used to predict whether humans will engage in risky or seemingly maladaptive behaviors?

Young males have higher mortality rates than young females (seems to imply that they are more likely to engage in risky/maladaptive behaviors)

Kaplan-What contribution do these papers make to understanding human foragers in the EEA?

a) 4 life history theories that contributed to intelligence (1) long lifespan, 2) extended juvenile dependence, 3) support of reproduction by older post reproductive individuals, 4) male support of reproduction b) humans v. chimps -humans exists in wide variety of habitats, eat lots of foods, flexibility in contributions to society between sexes and age groups **environmental adaptiveness**

Provide an example of a behavioral, developmental, genetic, and physiological adaptation.

a) Behavioral - cooking b) Developmental - longer growth period until adults c) Genetic - sexual reproduction d) Physiological - bipedalism

What is biological fitness, and why is it so hard to measure?

a) Biological fitness is the ability to survive to reproductive age despite environmental conditions, as well as successfully finding a mate and producing offspring which also survive. b) It is difficult to measure because it is dependent on more than one generation or individual. Also multiple factors contribute to it.

Know the difference between a genotype and a phenotype. On which does natural selection operate? Provide an example.

a) Genotype: genetic makeup of an organism -variability introduced through mutation and -gene recombination through sexual reproduction b) Phenotype: observable characteristics of an organism -how genes are expressed -variability influenced by nutritional, epidemiological, social conditions -genotypes code for phenotypes -natural selection acts on this ex: colored nose in old world monkey went away

What is plasticity (behavioral, developmental)? Explain why the height of boys in London has changed over time, and why it differs by social class at different points in history.

a) Plasticity, a term coined by Boaz, was "the old idea of absolute stability of human types must...evidently be given up and with it the belief of hereditary superiority of certain types over others". Meaning things change due to environmental variation. --phenotypic plasticity (environmental variation within genetic variation) and reaction norms (range of potential outcomes) --critical periods: "growth depends on more or less favorable conditions during development" ex: The height of boys in London has changed over time because of social status - I.E. upper class boys who went to prep school had better nutrition so they grew taller!

What is meant by "ultimate and proximate thinking in evolutionary biology? How do these relate to Tinbergen's questions?

a) Proximate causes-what mechanism enables the organism to exhibit the behavior? INDIVIDUAL LEVEL b) Ultimate causes-in terms of evolution, how and why did that behavior come to be? LEVEL OF SPECIES --Regarding Tinbergen's questions, proximate causation is mechanisms and development, ultimate causation is evolutionary and functional.

Who are the major food producers in modern foraging societies? Who are the net consumers?

a) Reproductive age males are the major food producers (as well as post reproductive females). b) Children and reproductive aged women are net consumers --children have not yet developed to the point of being able to fully contribute to the society. --reproductive women are expending all of their energy on reproduction, they don't have any to spare on food acquisition.

How does a chimpanzee skull compare to a human skull in terms of canine teeth, prognathism, and brain shape and size?

a) canine teeth which project more greatly b) Prognathism: greater level of prognathism (Jaw is protruding) c) Brain of chimp is more flattened and smaller in size compared to humans

Explain why bipeds evolved in the late Miocene.

a) late Miocene was when the environment shifted to a hot, dry, open terrestrial environment → b) limited food & resources highly dispersed over large area c) environment would require more energy efficient way to travel and get food & resources → d) bipedalism saves energy!

Volk & Atkinson-What contribution do these papers make to understanding human foragers in the EEA?

comparing data on hunter-gatherers & chimps -infant & child mortality as study of EEA -modern groups (foragers)=historical -continuation of EEA -show phylogenetic relationship of humans & chimps **infant mortality & society same**

What is "reproductive value?" What is the average reproductive value of all individuals in a stable population? Which individuals have the highest fitness?

expected reproduction of an individual from their current age onward, given that they have survived to their current age. -if a couple has 2 kids, 1 for each so most fit is more

What is a phylogeny and why is it useful?

groups of species that share a common ancestor -phylogenetic relationships form a basis for ID and classification of organisms (taxonomy) -helps us understand WHY certain adaptations emerge

Australopiths

hominid (not hominin) bc mostly arboreal and sometimes bipedal

Is it appropriate to apply evolutionary theory to the study of human behavior? Why or why not?

Evolution of humans (adaptations) : -behavioral -physiological -developmental -genetics Human behavioral ecology: the ways that biological adaptation and ecology combine to produce behavioral patterns; examines the adaptive nature of behavior (does it maximize fitness? is it adaptively adjusted to environment? conditional strategies) Conditional strategies: some strategies may be more ideal depending on the environment *humans act in way that makes them most fit-enhances reproductive success*

What is meant by inclusive fitness? Does it explain extensive cooperation observed in humans?

inclusive fitness: the ability of an individual organism to pass on its genes to the next generation -takes into account genes passed by organism's close relatives (kin share copies of genes) -2 of your offspring=1 of you --explain cooperation

What are some benefits of bipedalism? Why did bipedalism (probably) evolve? What conditions fostered it?

most imp SAVES ENERGY also: 1) Hunting (Refuted, as it has been shown that we were vegetarian until very recently) 2) Foraging 3) predator avoidance (Height advantage) 4) thermoregulation (less sun on body while running) b/c shift to hot climate, food disperded

Which hominin had the largest brains?

neanderthals

What are some major differences between the theoretical and methodological approaches of evolutionary psychology and human behavioral ecology?

Evolutionary Psychology: -applies evolutionary reasoning to psychological phenomena -uncovers mechanisms that underpin human behavior & selective forces that shaped those mechanisms -behavior is produced by specialized cognitive 'modules' that evolved in response to specific -adaptive problems in past selective environments --data collected through lab studies & surveys (standard statistics and experimental controls (select diverse group, more assumptions, control, causal inference, people sense they're being watched) -very specific to industrialized populations vs. Human Behavioral ecology: -typically observational -everyday conditions, less self-selection -naturalistic field studies (foraging, not industrialized) -comparison of behavior on multiple levels (between species, between populations, and between individuals of same population) natural selection & psych v natural selection & behavior

How do evolutionary and cladistics systems of taxonomy differ? Which in your opinion is preferable?

Evolutionary system: -overall similarity -humans different from most BUT related to apes (not preferable bc we are NOT closely related to apes, not more evolutionarily evolved (just differently) **we ARE more fit)) Cladistic: -cares only about genetics -humans more closely related to chimps -hominoids

Altruism has been a puzzle for researchers, philosophers, etc. for hundreds of years. The existence of altruistic behaviors was the driving force behind the development of such theories as group selection, kin selection, etc. Do you believe that altruism truly exists? Give examples and justify your answer.

Fitness of a gene depends not only on its effects on individual reproduction, the the reproduction of all the organisms in which it is housed. Thus, altruism exists if it benefits inclusive fitness (more likely to occur in social groups that are genetically similar). Examples: alarm calling in monkeys, meerkat watch guards, bees sting and die, chimps share meat

Be able to distinguish hominids from hominins. Was Ardipithecus ramidus a hominin? Were the Australopiths?

Hominid: humans, living apes, extinct humans and apes from Miocene/Pliocene/Pleistocene Hominin: ANY member of the family hominidae --they are humans or anything that is bipedal. Ardipithecus Ramidus (Ardi): -EARLY hominin -early biped, many ape traits ---human pelvic/bipedal ---long arms, short legs, long fingers ---flat, gripping feet ---body hair

Know the difference between homologies and analogies, and be able to provide examples for each.

Homologies: similarity organisms share because of shared ancestors (principle factor in taxonomic grouping) ex: all mammals have pentadactyl limb Analogies: similarities between species because of similar selective pressures (NOT common ancestory) ex: bat and bird both have wings, but do not share common ancestors

What is a mating system? How are mammalian mating systems constrained? How do they vary?

How animals find mates and care for offspring -sexual reproduction -Female gestation -Female lactation They vary by: -Parental care (female care is critical in mammals, male care varies) -Type of mating system (monogamy/pair bonding, polyandry-one female has more than one male, polygyny-one male has more than one partner, polygynandry-2 or more males have exclusive relationship w 2 or more females)

Timbergen's Q's--Know how to apply them to behavioral traits.

Human Intelligence: 1) frontal lobe grew 2) learning and nutrients-growth in brain 3) evolved through natural selection 4) survival, increased efficiency (food use, tools, etc.) Food Sharing: 1) hormones make us feel good, inherent sense of fairness 2) learning from elders 3) some natural incentive to care (more in humans, systemized 4) brain grow, benefit share-back

Compare food sharing in humans (across genders, age groups, within and across families) to that in chimpanzees. What characterizes human sharing? What might explain it?

Human food sharing: -kids are consumer -middle aged men/post menopausal women producers *hunting luck* -men and woman-nutrients -regular supply of lipids=better brain ---humans have to learn skills (long juvenile period) Chimp food sharing: -mothers w infants -small prey not shared (large shared)

Under what circumstances do mammalian males invest in their offspring? Under what circumstances do mammalian males invest in mating effort?

Invest in offspring: -If mates are scarce -If paternal care improves offspring fitness Invest in mating effort: -If mates are abundant -If one parent can raise offspring

What are the major energetic life history trade-offs, according to life history theory? How do they change across the human life course?

Life History Theory: shaped by natural selection to maximize fitness comparative approach to study of the timing of events through the life course -Life history "strategies" -General trade-offs Between the three main categories: a) Maintenance, b) Growth, and c) Reproduction. -Focusing on any two, diminished the third e.g. growth&reproduction leads to senescence (aging), as energy is lost. i.e. Growth is favored during childhood phase, while reproduction is favored during adult phase

Know the main demographic parameters used to construct human life history tables. Why are these important? How might they influence behavior?

Lx = probability of surviving up until age x (number / number initial) Mx = fertility at age x Qx = probability of dying during age interval x (number dead/number) Sx = probability of surviving during age interval x (number survive/number) Goal is to figure out which life history trajectory is optional. Age specific mortality and fertility rates are not the same for males and females due to sexual selection. I.E. years of highest fertility in males is highest during their peak hunting success years.

Under what circumstances do male soapberry bugs practice mate guarding? Is this genetically canalized or the result of behavioral plasticity?

Males mate and then guard females after copulation. -Mate guarding dependent on the sex ratio (males : females) -genetic canalization: fixed behaviors regardless of environmental conditions -behavioral plasticity: flexible response to some environmental cue that is heritable i.e. when there are more males than females, males practice mate guarding. when there are equal numbers of males and females, males DON'T practice mate guarding.

What is meant by asymmetry in reproductive potential between males and females? What is the limiting factor in male and female reproductive success, respectively?

Males: -higher reproductive rate -reproductive success reliant on female -more variable Female: -limited by resources -more energetically expensive -eventually STOPS being beneficial to have kids

What is an adaptation? Are all existing traits and behaviors necessarily adaptive? Provide an example of a uniquely human adaptation.

-Beneficial adjustment to the environment -Aimed at improving performance in the face of environmental stresses -increase number/quality of surviving offspring -Measured as fitness outcomes Not all traits are adaptive! Some are neutral or the byproduct of trade offs Uniquely human adaptation: clothing! fire! whatever.

Describe the earliest bipeds (7-4 mya).

-7-4 Mya - early bipeds were just apes -Poorly represented in fossil record -Mix of arboreal and bipedal traits