Final Flashcards
Shared primate trait “clusters”
3
- Tree dwelling
- Dietary flexibility
- Extensive parental care
What morphology characterizes primates? (think of 3 things)
- Hand & foot traits representing flexibility
- 360 degree arm flexibility (collarbone placement)
- Straightened spine orientation
- 4 types of teeth
- Reduced snout & smaller area of brain for smell
- Cranial/soft tissue changes tied to vision
- Comparatively large & complex brains
- Direct contact placenta
- One set mammary glands
Where are primates found?
New World (central & South America), Old World (SEAsia, SAsia, SSAfrica)
Usually tropical or subtropical
Varied habitats!!
Major primate division
Strepsirhines and haplorhines (tarsiers controversially placed)
Division of simiiformes
Catarrhini (OWM & Hominoidea) vs Platyrrhini (NWM)
Division of Catarrhini
Old World Monkeys vs Hylobatidae (gibbons, siamangs) and hominidae
Division of hominidae
Orangutans, African apes & humans
Strepsirrhine features
- Rhinarium (olfactory membrane)
- Tapetum lucidum (eye shine & night vision)
- Post-orbital bar
- Vertical clinging and leaping
- SMELL = primary sense
Haplorhine features
- Fully enclosed eye socket
- No rhinarium or tapetum lucidum
- VISION = primary sense
- Bigger comp. brain size than strep
Ape features
No facial hair or tails
Full shoulder rotation
Bigger CBS than monkeys and longer juvenile development
New vs Old World Monkeys
New World monkeys have prehensile tail
OWMs more likely to live on ground
Surprisingly similar given 30 million yrs separation
How are primates socially complex? (3 reasons)
- Differentiated social relationships - lifelong, invest in friendly behavior
- Socialize preferentially with kin - one sex typically leaves, other forms matri- or patrilines
- Triadic awareness - knowledge of outside relationships
Deprivation studies
Studies showing infants seek care and contact with their mothers and thrive the more socialization they get
Characteristics of play
- Unpredictable, repeated sequence of movement
- Open mouth and specific vocalization
- Restraint
Types of play
Object, locomotor, social
Factors affecting play
Age & sex (F more than M as they age), social systems (solitary or not), resource scarcity
Why play?
Practice adult technical, social, locomotor skills
Physical function of grooming
Remove bugs from fur; relaxation
Social function of grooming
Establish and maintain social relationships
What function replaced grooming in humans?
Possibly language/gossip
Function of non-reproductive sexual behaviors
- Paternity confusion to prevent infanticide
- Bonding
What is aggression?
Behavior with intention of causing physical injury
What is agonism?
Behavior which carries threat of aggression (e.g. baring teeth)
Contexts of aggression
Interspecific - between species (competition or predator prey)
Intraspecific - within a species (competition between groups or within group)
Sex differences in aggression
Equal in amount, males more severe and likely to seriously wound each other due to risk to F’s offspring
Characteristics of aggression
Signaling first, then chasing, fighting using limbs (no weapons), possibly recruitment of others
Dominance relationships
Multiple fights resulting in a pair/ hierarchy where one always receives resources after winning all or most of the fights
Long-term consequences of aggression
Dominance hierarchies form and aggression becomes less common
Frequency of lethal aggression & why
Rare - logistically difficult to kill someone from your own species
Cases of lethal aggression
- Infanticide (males killing unrelated infants to gain more access to females)
- Coalitionary violence (chimp males set out to kill neighbors, 5-15 on 1, and gain territory or resources)
Frequency of aggression
Daily in non-human primates
Reconciliation
When individuals make friendly physical contact very soon after a fight (~2 mins)
Consolation
When a third individual goes to make contact after two other individuals fight
Traditional view on costs/benefits of aggression
Get whatever you were fighting for, but lose time & energy and risk injury
New view on costs/benefits of aggression
Still get what you wanted - BUT risk losing valuable social relationships if no reconciliation
Why is there natural selection for reconciliation behaviors?
Animals can maintain interdependency in groups, benefitting themselves & community
Why do individuals reconcile or console?
Reduce stress - observable w less self scratching
Why study primate communication?
- Window into primate minds & social systems
- Language = unique in humans, can this help us understand it better?
Types of communication signals
Olfactory, tactile, visual, vocal acoustic, nonvocal acoustic
Traditional view of primate signals
Limited, only convey info about sender’s identities
What makes language unique?
- Words defined by other words and given meaning by speech community
- Can represent outside world and abstract concepts
- Constantly learning new words and completely new word combinations
- No need for formalized instruction as a toddler to understand language
Shared Intentionality Hypothesis
As cooperation grew more important in early hominins, language evolved to allow better communication
Kin selection meaning
Natural selection favors behaviors which allow close kin to pass on genes b/c these are exact copies of an individual’s genes
Inclusive fitness
Your fitness + your relative’s fitness / their distance from you
Kin selection case study
Vervet monkey alarm calling - will call out to warn kin about a predator, but not if no kin present
Reciprocal altruism meaning
Doing a favor or helping someone who then returns it later
3 necessary conditions for reciprocal altruism
- Frequent association
- Long life span
- Good memory
Reciprocal altruism example
Chimpanzees will groom each other and give each other food reciprocally
Sex differences in parental incentive
F - limited by ecology/nutrition
M - limited by access to females
Common forms of sex selection
M - intrasexual (compete w each other for females)
F - intersexual (look for good males)
What group dynamic is infanticide most commonly found in?
1 male - many females
(other males want to be the one)
Costs of living in a group
Competition for resources, easier for predators to find you & your relatives
Benefits of living in a group
More individuals can detect predators/provide food
Relationship between ecology and the sexes
Ecology -> females -> males
What makes up a social system?
Social organization + social structure + mating patterns
Social organization
Group size, sex ratio, cohesion, dispersal patterns
Social structure
Individual relationships in a group, both positive and negative
Mating patterns
Polygyny
Bonded pairs/monogamy
Promiscuous
Polyandry (very rare)
Dispersed sociality - def & example
No permanent social group for adults - both M and F disperse
Ex: orangutans
Pair bonding - def & examples
1 M, 1 F, many offspring
Lack of sexual dimorphism and males more helpful
Ex: gibbons
Polygyny - def & examples
1 M, many F
Males are huge, competitive to be the one male in the group (also sole and group males)
Ex: gorillas
Many M, many F - def & examples
Many different setups
Ex: chimpanzees
Territorial, females disperse and males bond, promiscuous mating
