Anthro-Midterm #2

What is primatology?

Study of bio, evolution, taxonomy, + behavior, of non-human primates

what are the Interdisciplinary of primatology?

• Intersection btw--> mammals + anthropology (mix of these studies)

  • Primates--> 1 taxon mammals

  • Humans are primates

  • Non-human primates= models for human evolution--> closest relatives

  • Primate behavior, ecology, + conservation are studied as part of ecosystem

what is Behavior?

Anything an organism does in response to external/internal stimulus--> conscious or not

External stimulus vs. Internal stimulus

• External stimulus: changes to conditions outside body

  • Ex. Smell, touch, vision

• Internal stimulus:  changes to conditions inside body

  • Ex. Hunger, thirst, sleepiness

what’s the difference between Ethology vs. Behavioral ecology? explain what is the ecological + evolutionary perspective

• Ethology: study of animal behavior

  • From Greek--> ethos= character + -logy= study of

• Behavioral ecology: study of animal behavior from ecological + evolutionary perspective

  • Ecological perspective: all aspects of organism's enviornment

    • Ex. Its habitat, other individuals, predators, parasites

  • Evolutionary perspective: diff behaviors have evolved thru natural selection

 

what are the 3 main topics in behavior ecology?

1. Social strategies

2. Reproductive strategies

3. Cognition

Social strategies:

what is Social strucuture + some aspects of it? what is it influenced by?

• Social strucuture: composition, size, + sex ratio of a group of animals

• Some aspects of social structures:

  • Relationships btw individuals (aggressive/affiliative behaviors)

  • Dominance system

  • Territoriality

• Influenced by factors:

  • Life history: how long they live

  • Body size <--> Metabolism <--> diet

  • Activity patterns

  • Resources distribution

  • Predation + human pressures

Reproductive strategies:

Male vs. female repro strategies

what are the 3 different levels of mating systems?

• Females:

  • Invest more in offspring (preg, lactation, caring)

  • Need lots of resources + security for offspring

• Males:

  • Invest less in offspring

  • More advantageous to repro lots

• Diff mating systems: mono, polygny, polyandry, polygynandry--> have diff levels of:

  • Sexual selection: natural selection arising thru preference by 1 sex for certain characteritics in individuals of other sex

  • Sexual dimorphism: derived from sexual selection (ex. size + coloration)

  • Parental care: from mother, father, + other members (=alloparenting)

Cognition:

how is intelligence measured?

How do primates communicate?

What is culture?

• Intelligence: problem-solving, self/non-self, + thought-processing

• Neurological aspects

• Communication: how its invovled in primate + compared to humans

• From communication to language

  • Auditory, olfactory + visual communication

  • Humans are only primates capable of articulated language--> cuz anatomical adaptations (larynx shape + prescence of vocal cords)

• Culture: innovations that are spread + maintained + w/in generations by social learning

Why study primate social and reproductive strategies?

• To understand the link between behavior and morphology (e.g. sexual dimorphism)

• Modern primate behavior can inform the interpretation of fossils

• Can inform on social and sexual systems of our ancestors

Why study primate cognition?

• To understand the link between behavior and morphology (e.g. vocal communication)

• Because we need to identify the factors that made these abilities adaptive in our common taxon (e.g. the apparition of cultural traditions)

• Can help retrace our own evolutionary history

Why study primate conservation strategies?

• To better plan their protection

  • Conservation areas (national or private)

  • Rehabilitation programs

  • Captive breeding programs (network of zoos worldwide)

what is Adaptation?

short term change w/in a species (microevolution)

what is Evolution?

long term change--> results in new species (macroevolution)

How do species change over time?

• By natural selection

  • Natural selection: primary mechanism of biological change over time (adaptation + evolution)

who proposed natural selection? what are the 3 observable facts?

- Proposed by Darwin-"On the Origin of Species by Means of Natural Selection" (1859)

- Based on 3 fundamental observable facts:

1. Variation

2. Inheritance

3. Overproduction

what is Variation?

• Lots of variation w/in + btw species

  • Random mutations

  • Random genetics recombination

  • Non-random mate choices

what is Inheritance?

• Variation passed from parents to offspring

what is Overproduction?

There are always more offspring born than can or do survive to adulthood (competition)

Who survives to adulthood? Who doesn’t?

Who survives to adulthood?:

• Those who happen to have variation (morphology/behavior) that helps them survive

Who doesn't?:

• Those who have variation (morphology/behavior) that doesn't help them survive

• The environment naturally selects some variants over others

which one do we need, survival or reproduction?

• Survival alone is not the important thing in understanding evolution by natural selection

• Survival + then reproduction are the keys to understanding adaptation + evolutionary change over time

what is Fitness?

• An individual's ability to reproduce successfully compared to other members of the same species

• Those traits possessed by individuals w/ high survival + reproductive success--> will be passed to future generations at higher rates

• The environment naturally selects some variations (some individuals) over others to survive + reproduce

• The population, over time, becomes better adapted to local environments

Adaption/Evolution by Natural Selection

• The differential survival + reproductive success in each parental generation (NATURAL SELECTION)--> leads to change in frequency of traits from 1 gen to the next (ADAPTATION/EVOLUTION)

what happens if traits are well suited to the enviornment vs. when they’re not?

The traits that:	The traits that:
Are well suited to the enviornment	Are NOT well suited to the enviornment
Give individuals an advantage in survival + reproductive success…	Put indiviudals @ a disadvantage in survival + reproductive success
+ will appear in increased freq in future generations	+ will appear in decreased freq in future generations

give an example of natural selection producing adaptation

peppered moth

what are 4 points illustrated about natural selection + change in peppered moths?

1. Evolution (change): operates on population--> X individuals moth ever changed color

   • Indiviudals X "evolve"

2. Natural selection: operates on the indiviudal

   • Indiviudals survive + reproduce or not

3. Variation had to be there in the 1st place

4. There is X such thing as absolutely better variant

   • Depends on the enviornment

what is Sociobiology? what are the 3 principles?

• Applying evolutionary principles (natural selection) to behavior

• Trying to understand how behavior might be naturally selected/adapted/evolved

• Asking how behavioral variations give indiviudals advantage in survival + repro

• Developed in 1960's + 1970's

• Development of 3 main principles:

1. Kin selection

2. Reciprocal altruism

3. Parental investment

What is altruism?

• Behavior that potentially improves survival + repro success of recipient while potentially endangering the actor

• Behavior that benefits the recipient @ cost to actor

Why is altruism hard to explain?

• Behavior that increases survival + repro success of actor= will be passed on @ higher rate to next gen (will be favored by natural selection)

• Behavior that decreases survival + repro success of actor= will X be passed down

How was altruism thought to get passed on?

Originally--> altruistic behavior was thought to evolve cuz it was good for the group

What was the problem w/ group selection?

• Wynne-Edwards (1962)

  • Defined natural selection acting on group rather than indiviudal

  • For it to work--> groups w/ altruists would have to have higher fitness than those w/o altruists

    • But altruists may have decreased repro success

    • Selfish indiviudals would have better repro success

  • Altruists would X be passing on their genes

what are the opinions on Group selection?

• Group selection was rejected cuz evolutionary biologists X see how it could work

• Natural selection only makes sense if it acts on the individual

  • Each indiviudal striving to max their own repro success

• Some argue that group selection should be reconsidered

Answer to how could altruism have evolved

• Origin of sociobiology

• Altruism evolved X by group selection BUT by kin selection

  • Kin selection: 1st principle of sociobiology

  • Hamilton 1963 + 1964

Kin selection

• Each individual shares genetic material w/ their relatives

• Its possible to have some of ur genes represented in the next gen (even if u X repro) if ur relatives were reproductively successful

what are the 2 Important new concepts introduced w/ kin selection?

1. Natural selection: operate on genes rather than individuals

2. Inclusive fitness: individual fitness + effect upon fitness of relatives

what is Hamilton's rule? what are the 3 variables?

• 3 variables:

1. The cost ('c') to the actor's individual fitness

2. The benefits ('b') to the recipient's individuals fitness

3. The degree of relatedness ('r') btw actor + recipient (the proportion of genes shared by common descent)

• Individual will be selected to help relative whenever--> c < b x r

Most altruism in primates does occur btw kin, what are 3 outcomes from this?

• Coalition formation- supporting ur kin in agonistic encounters

• Food sharing

• Social grooming

Does altruism occur btw non-relatives?

• Yes

  • Altruism btw non-relatives X be explained by kin selection

  • Alternative explanation proposed: reciprocal altruism

Reciprocal altruism (Trivers 1971)

• Helping behavior btw non-relatives

• Individuals help others so that they will get help in the future when they need it (lowkey like karma)

  • X need to worry about passing genes, just focus on increasing survival chance

  • Grooming/support given to indiviudal will be reciprocated later--> indiviudals will cease to help "cheaters"

Reciprocal altruism: 2 requirements

1. Sociality: indiviudals must have the opportunity for repeated interactions

2. "helping" indiviudals are of similar abilities (rank, size, etc)

Does "helping" behavior occur btw non-kin w/o evidence of reciprocal altruism?

• Yes

  • These types of behaviors could also evolve thru mutualism

Mutualism

• Interaction btw 2 organisms where each gains a fitness benefit

• These interactions can look like co-operation

  • Ex. A bee pollinating a flower, a colobus + its gut bacteria--> beneficial to both organisms

  • Ex. 2 males in coalition--> working together may help both of them in the long run (ex. To take over a group) but they will turn on e/o when they X benefit

• X altruism cuz there is X overall cost to the actor in helping

what is Social attraction?

• Individuals seeking out proximity to e/o outside of enviornmental stimuli

  • More than a response to predation, to localized food resources--> means there's benefits for being in a group

African wild dogs social system

• Communal pup raising + feeding

• Tight social bonds associated w/ spreading of diseases + decline of wild dog #'s

  • Spread of infectious diseases--> cuz they would play bite e/o faces

Spotted hyenas social system

• Social life more similar to Cercopithecines than other social carnivores (+ other species of hyenas)

• Despotic (strict) hierarchies

• Coalitions are important

• Btw-group conflict

Lions social system

• Females have complex social relationships

• No dom hierarchy--> egalitarian (all are same level)

• Strong btw-group competition

• Cooperative hunting--> raising young + defense against male infanticide

African elephants social system. what features are in old matriarchs?

• Female philopatric: females stay together for life

• Complex social strucutre based on strong matrilineal relationships

• Old matriarchs:

  • Hold high ranks

  • More finely honed social skills

  • Lead group movement

  • Age is directly correlated to group repro success

 

why is sociality X the key to adaptation?

• Argued that sociality is X the key adaptation for other species as its for primates

• Combo of:

  • Differentiated w/in group relationships

  • Marked social boundaries

  • Kin-based social relationships

  • Use of allies + coalitions in some species is unique to primates

what are 2 Disadvantages to group living?

1. Intra-group competition:

• More competition for food--> cuz members of same group are always nearby

2. Increased vulnerability to infectious disease

what are 2 Benefits to group-living?

1. Resource defense

   • Being in a group improves access to resources compared to being alone

   • Defending food

   • Finding food

   • bigger group = more encounter wins

   2. Predation defense hypothesis

• Being in a group offers better protection from predators

  • Collective detection

    • More eyes + ears to detect predators

  • Dilution effects

    • Each individual has less of a chance of being caught

  • Deterrence

    • Mobbing can scare off predators

  • During flight

    • Swarming confuses predators

Resource defense vs. Predation defense

Resource defense	Predation defense
Large groups have better access to food patches	Terrestrial primates live in larger groups than arboreal + some primates species adjust group size to risk of predation

2 theories are X mutually exclusive

Other benefits once you are grouped. name 3

• Mates are readily available

  • Easier to monitor repro state

• Increased feeding rates due to decreased individual effort towards vigilance for predators

• Females + their young--> may benefit from male protection from conspecifics

  • Infanticide protection

what is Sociality?

• Basic unit of species is difficult to establish

• Identify group--> animal count to establish membership

• Looks @ interactions btw individuals

  • Social group, 'maintained sociality'

What behaviors show strong relationships btw primates? name 3

• Affiliation:

  • Grooming

  • Huddling (ex. For warmth)

  • Proximity maintenance (attraction)

• Agonistic support:

  • Coalition formation--> to have back-up + protect group

• Minimal aggression:

  • Tolerance of proximity when feeding

Male-biased vs. female-biased dispersal

• Male/females leave group

Matrilineal vs. Patrilineal

Descendants from mom/dad side

Male-philopatry vs. female-philopatry

living their lives in the group into which they were born

female-bonded vs. non-female bonded

when females form bonds/relationship w/ e/o

Prefix: "mono-", "uni-", vs. "poly-", "multi-"

mono/uni= 1 partner

poly/multi= 2+ partners

• Suffix:

  • -gamy

  • -gyny

  • -andry

• Suffix:

  • -gamy= mating

  • -gyny= refers to female

  • -andry= refers male

Male-biased dispersal. give an example

• Males leave natal group

• Females are resident in natal group

• Female are matrilocal

• Females form matrilines

• Group is female-bonded

  • Adult-adult female affiliative relationships are more predom than adult female-adult male OR adult male-adult male

• Ex. Cercopithecines (baboons, macaques)

Female-biased dispersal. give an example

• Females leave natal group

• Males are resident in natal group

• Males are patrilocal

• Males form patrilines

• Group is non-female-bonded:

  • Adult male-adult male affiliative relationships are more predom than adult female-adult male OR adult female-adult female

• Ex. Chimps (red colobus)

Both sexes dispersal. give an example

• Both sexes can leave the natal group

• Both sexes can remain resident in natal group

• Neither sex is predom resident

• Relationships are X based on matrilineal/patrilineal descent

• Neither sex is bonded + females tend to form strong bonds w/ alpha male

• Ex. Black + gold howlers, black + white colobus

what impacts does dispersal have?

dispersal impacts which sex has kin w/in group + which relationships are predominant/important

does male, female, and box sexes include all dispersal patterns? give an example

No.

Ex. Ursine colobus (Colobus vellerosus)

• All males disperse

• Female dispersal is facultative

  • Only some females disperse

  • May occur later in their life instead of @ sexual maturity

• Both sexes show parallel dispersal

• Founded by Drs. J. Teichroeb + P. Sicotte found

what is Parallel dispersal? what are the 2 requirements?

• Individuals emigrating either:

1. w/ other group members

2. Into groups w/ familiar individuals

   • Often members of an age-cohort transfer together

what are 3 Benefits for parallel dispersal?

1. Coalition partners aid their entrance into new groups

2. Individuals can maintain ties w/ related individuals--> even when they change groups

3. Individuals have increased survival--> cuz more members during transfer= greater protection from predators

who proposed Sexual selection? what was it used for?

• A mechanism proposed by Darwin--> explains sexual characterisitics

• Darwin realized that some traits were impossible to explain w/ natural selection

• Instead of aiding individuals in survival--> these traits seemed detrimental

what are Secondary sexual characterisitics? give examples of it.

• Features of sexual dimorphism

• Male/female distinctions that appear @ puberty

• Distinctions btw adult males + females that go beyond basic repro diff

• Ex. Diff in size, coloration, weaponry, shape, ornamentation

Why was another mechanism needed to explain secondary sexual characteristics? list 2

1. They are X easily explained by natural selection

   • X beneficial to survival

   • Can be detrimental

2. They X appear until adulthood

what’s the difference between Natural selection vs. Sexual selection?

Natural selection	Sexual selection
Emphasizes survival	Straight to repro
Emphasizes getting to adulthood	Once @ adulthood= sexual selection starts
Selective pressure--> physical enviornment + genetics	Selective pressure--> social enviornemnt
Operates in males + females equally	Operates on 2 sexes in diff ways

• Secondary sexual characterisitics X provide survival advantage= they can give individuals repro advantage

  • Even if survival is short= if they repro well during when they are in prime--> X matter for sexual selection

what are the 2 mechanisms that lead to evolution of secondary sexual characterisitcs?

1. Intrasexual selection: competition for mating partners (w/in sex)

2. Intersexual selection: mate choice (btw sexes)

3 Types of male-male competition

1. Contests

   • Physical attacks, threats, interference

2. Scrambles

   • Early search + detection of females= determines order of contact + sperm competition

3. Endurance rivalry

   • Time + energy spent seeking, attracting + defending mates, repro active

   • Harder to assess

how does secondary sexual characterisitcs affect Male-male competition (intra-sexual selection)

Secondary sexual characterisitcs give males repro advantage thru competition w/ other males

3 Levels of competition in male primates

1. Complete monopolization

   • Most successful strategy is to monopolize access to several females

2. Max copulations

   • If monopolization X possible--> males increase copulation freq while reducing rivals' copulation

3. Post-copulatory selection

   • If males X control copulation #s--> rely on post-copulatory mechanisms to increase fertilization chances w/ fewer mating (ex. Sperm competition)

what are the consequences of male-male competition? list 2

1. bigger body size than females

2. larger canines than females

how does secondary sexual characterisitcs affect Female choice (intersexual selection) with males?

Secondary sexual characterisitics give males repro advantage by making them more attractive to females

Why should female mate choice exist? list 2

1. Fisherian runaway selection

2. Benefits for females

what are the 4 criteria for Fisherian runaway selection

1. Female choice favors traits of males also favored by natural selection

2. Offspring--> males likely carry advantageous trait + females prefer it

3. Across gens--> results in runaway process

   • Positive genetics correlation btw choice of trait + trait expression

4. Process stops when trait is so highly developed that incurs/not worth in costs for survival

what are the direct + indirect benefits females get from choosing their mates?

• Direct benefits: protection from other males--> access to resources, less likely to get parasites/diseases from the copulation

• Indirect benefits: paternal care, inbreeding avoidance + "good genes" for offspring

what is the Good genes models? list 2 + give examples

• Handicap models

  • ornamentations reduces male survival enabling females to assess individual males ability to survive despite burdensome ornament

  • Ex. Long tail, large horns--> X functional in combat

• Viability indicator models:

  • Females assess male characteristics cuz they indicate secondary, less apparent trait determining male fitness

    • Male traits can indicate inherited features about males

  • Ex. Testosterone level, parasite load, body size, fighting ability, age, tenure stage

How do female choose mates? list 3

• Repro physiology:

  • Synchronized estrus periods in females reduce male monopolization

  • Females can conceal/advertise their ovulation (ex. Sexual swellings)--> influencing male behavior + mating

• Mating cooperation:

  • Positive female choice (ex. Soliciting certain males)

  • Rejection

• Post-copulation

  • Cryptic female choice (ex. Genital enviornment)--> influence which male fertilizes egg

    • Ex. pH levels--> females decrease pH for sperm that is genetically similar to them

Trait is sexually selected if… list 5

1. Sexually dimorphic

2. Varies w/in pop

3. Individuals can discriminate btw its variants

4. Individuals show repro preference for specific variant

5. Variants of traits are related to diff repro success

give an example of a trait being sexually selected

1. Sexual dimorphism- only in females

2. Female baboons show variation in sex-skin swelling

3. Males use swellings as a cue of fertility

4. Males show more arousal to females w/ more developed swelling + compete more

5. Males copulate w/ females more during higher swelling

give examples of Sexually selected traits

• Behavioral displays

• Acoustic displays

• Ornaments

• Weapons

• Pelage/plumage

• Skin coloration

• Chemical signals

  • Wasting energy shows possession of energy

give an example of Behavioral displays as indicators. what’s the purpose of it?

• Stiff-leg display

  • Colobus monkeys (Colobus verllerosus)

• Males vary in their expression of these behaviors

  • Ex. High ranking males display more than low ranking males

• Males displays decreased in vigor over time

• Displays were targeted to other groups + males

give an example of Acoustic displays as indicators. what’s the purpose of it?

• Wahoo

  • Yellow baboons (Papio cynocephalus ursinus)

• Rate + duration are correlated w/ a male's competitive ability

• High ranking males

• allow listeners to assess a male's competitive ability

give 2 examples of Ornaments as indicators. what’s the purpose of it?

• Blue testes

  • Vervets (Cercopithcus aethiops)

  • Vividness of coloration represents male quality + predicts outcomes of aggressive encounters

• Throat sac + cheek pads

  • Orangutans (Pongo pygmaeus)

  • functions as male-male competition

  • Female choice is secondary

• Call transmission + reflection

give an example of Weaponry as indicators. what’s the purpose of it?

• Teeth

  • Madrills (Mandrillus sphinx)

• Asymmetry is correlated w/ measures of sexual selection--> includes canine dimorphism, canine size, mass dimorphism, + intra-male competition

give an example of Skin coloration as indicators. what’s the purpose of it? which males would have redder chests?

• Red skin in primates often represents testosterone level

• Chest patch

  • Geladas (Theropithecus gelada)

• Males w/ redder chests have higher quality

1. Leader males--> only males w/ repro access to females= have reddest chests

2. w/in leader males--> males w/ large units (>6 females)= have redder chests than males w/ small units

what are 3 primates that have coloration indicators?

• Uakari (Cacajao calvus)

  • Lack of pigmentation + intricate capillary system

  • Red head of uakari monkeys fades when they are ill

• Rhesus macaques (Macaca mulatta)

  • Skin becomes bright red during mating season w/ fluctuation in hormones

  • Evidence for female choice of more vivid skin

• Mandrills

  • Consistent thruout year

  • Vivid coloration indicates quality

  • Fatted rump is an honest indicator of condition

    • Female choice

give an example of Chemical signals as indicators. what’s the purpose of it?

• Ring-tailed lemur (Lemur catta)

  • Higher ranking males perform more olfactory displays (scent marking)

  • Scent marking is costly

  • Females showed mating preference for those displays

why is Sexual selection difficult to study in primates? list 3

• They live a long time + repro slowly

  • Determining their life time repro success take 20+ years

• Long-term social relationships occur

  • Hard to determine why a female prefers a male

• Males often use sexual coercion to mate w/ females

  • Male X be preferred but female mates w/ him anyway

what does Parental investment explain? why does parents invest so much to offspring?

• Parental investment explains sex diff in behavior + morphology

  • Reformulation of Darwin's theory of sexual selection

• Any investment by parent in individual offspring that increases offspring's chance of survival= repro success @ cost of parent's ability to invest in other offspring

  • PI is only after conception

• Investment that a parent makes in 1 offspring= decreases ability to invest in others

what are 3 potential conflict + competition in parental investment?

1. Parents + offspring (weaning conflict)

• Offspring wants to get max out of parents

2. Successive offspring (sibling rivalry for core/attention)

3. Parents (battles of sexes)

what are the 3 reasons that male + female repro strategies + behavior are different?

1. Diff levels of parental investment

2. Diff variance in repro success (lower potential repro output for females)

3. Diff limiting factors

Diff levels of parental investment:

• quality

• give care?

Females	Males
Quality: They choose males that will provide assistance, good territory, good genes	Quality: Go for as many fertilizations as possible + move-on--> little or nothing to lose
Primary care-givers	X give care

Variance in repro success:

• size of gametes

• number of gamates

• gestation?

• lactation?

• inter-sex variation?

• offspring limited by?

• competition?

Females (high)	Males (low)
Large, nutrient-rich egg	Tiny sperm
1 of 400	1 of 4 bil
gestation	no
lactation	no

Female primates	Male primates
LOW inter-female variation= similar #s of babies X diff btw least vs. most successful females relative to male diff	HIGH inter-male variation= males could be winners or losers 1 male can be responsible for 100% or 0% of offspring
typically have X offspring where X = repro lifespan ÷ interbirth interval (time btw 2 births)	Limited by social factors, copulation time + sperm
	Stakes are higher for males--> competition is more intense

Limiting factors: males vs. females

what are 4 aspects of Sexual conflict?

• Intersexual coercion is part of sexual selection (3rd principle of sexual selection)

  • proposed by Smuts

• Sexual coercion by males

  • Behaviors--> physical attack, harassment, intimidation, + interruption of copulation used by males to dom females + control pop

• Sexual coercion is viewed as sexual conflict

• Sexual conflict of repro interest in males + females are asymmetrical