ANT 200: Foundations of Behavior Module 3 (Evolution of Behavior) Exam Review

animal behavior

How individuals respond to internal and external stimuli (social, structural, physiological)

ethology

a subfield of biology that studies character that appeared fully functional from the first time it performed and were elicited by some cues

• is european tradition

• biology

• birds, insects, fish

• careful field observations

• instinctive behavior

• fixed action pattern

fixed action pattern

instinctive behavior that is highly stereotyped

Charles Darwin

Niko Tingerben

Karl Von Frisch

Konrad Lorenz

early ethologists who used the “watching and wandering approach.”

Karl Von Frisch

studied how honey bees have color vision using the blue experiment and decoded their waggle dancing

Konrad Lorenz

studied duck imprinting

Behaviorism

the american version of ethology that mainly focuses on whether behavior comes from experience

• works with rates, primates, dogs

• lab controlled variables

• learned behavior and conditioning

• psychology

equipotential

any two stimuli can be associated, regardless of their nature

respondent behavior

involuntary response to a stimuli

operant behavior

associate a voluntary response to a reward or consequence 

all animal behavior can be accounted by with a few rules in Behaviorism

equipotential

it is either respondent or operant,

little consideration of evolution or natural behavior,

animal behavior is based on labs

think about Pavlov’s Law of Association

Pavlov’s Law of Association

animals (and humans) can learn to associate a previously neutral stimulus with a meaningful one, leading to a conditioned response.

Representation in the field of ethology

Margaret Altmann: studied hormones in the blood of livestock and behavior of mammals on their sexual cycle

Charles Turner: showed how insects are capable of learning

Kinji Imanishi: studied wild macaques, used long term observations

Timbergen’s 4 questions for studying behavior

causation and development

• this is proximate

funciton and evolution

• this is ultimate

proximate

an explanation in terms of immediate factors, relevant and measurable at a current time or during development (What and how)

ultimate

an explanation in terms of the process and force of evolution

causation

sensory-motor mechanisms

development

genes, environment, learning

evolution

historical pathways

function

survival value

Example of these Timbergen Questions: “Why do we Eat”

Causation: stimuli that elicits the behavior

Development: how does the behavior change with age

Evolution: how does the behavior evolve/compare with similar behavior in related species

Function: how does the behavior affect the animal’s chances of survival and reproduction

pitfalls to avoid in behavioral study

• assuming complexity of a behavior

• ignoring umwelt

• ignoring natural proclivities and capabilities

• statis (not using modern technology)

umwelt

perceptual world in which an organism exists and acts as a subject

what does dog/fox domestication tell us about behavioral evolution?

it can be slow, and also happen very quickly

it was based on using just one trait

unintended consequences due to correlated traits

natural selection acts on variation correlated traits to maintain variation

epigenetics

The interaction of genes and environment in terms of how they affect behavior

• ex. Prenatal epigenetic changes due to maternal stress can cause increased anxiety in offspring

group

A number of animals which remain together in or separate from a larger unit and mostly interact with each other

what are groups different from?

territories and home ranges

what and how many systems make up a social system?

4 systems:

• social organization

• social structure

• mating system

• care system

Social Organization

focuses on Group size, group composition, and kinship pattern

social structure

social interactions, communication, social relationships, and social bonding

mating system

mating pattern and who gets to reproduce

care system

who cares for the young? parental care basically

what are the 6 types of social groups

solitary (orangutans)

pair bonded (gibbons)

group living

• multi-male, one female (baboons)

• one male, and multi female (gorillas)

• multi male, multi female (chimps and bonobos)

solitary group

significantly correlated with nocturnal behavior and animals who forage alone (have no dietary specialization). They only gather together to mate and sleep, and are often small in body size.

• tarsiers and aye-ayes

paired primates

pair living is the rarest group that seems to have evolved independently from the other social groups. It is related to parental care and infanticide avoidance

• owl monkeys

one female, multi male

may start out as a breeding pair, but a second male joins the group to mate with the female. related to twinning and paternal care

• pygmy marmoset

one male, multi-female

a silver back male will be the single breeding male, both females and males may disperse, but about 30 percent of gorillas in Rwanda have more than one silverback

multi-male, multi-female

this is a fission-fusion organization, and grouping happens due to food, females estrus status, intergroup interactions and relationships

multi-level societies

are groups that have multiple social organizations within it and is made up of 3 levels

• 1st level: has about 1-12 females and 2-15 males

• 2nd level: (bands) has about 2-27 reproductive units and several all-male

• 2.5th level: (herds) 60 units from different bands and only together for a short time

• 3rd level: (communities) 1-4 bands with overlapping home ranges

why do animals form groups?

benefits to groups

• dilute and fight against intruders and predators

• care for offspring

cons to groups:

• diseases

• infanticide

• social stress and competition

groups are socially favored when?

predation pressure is high and group defense if beneficial

group size is constrained when?

high resource competition and disease run rampant

the socioecological model

a social organization model that explains female groupings and how male groupings follow the females

what creates female groupings?

predation pressure and the cost of pregnancy and lactation

socioecological resources and its linked competition

clumped resources

• contest competition

• fruits and stuff

dispersed resources

• scramble competition

• grass and shit

high competition within a group does what to females?

makes is despotic and nepostistic

despotic

strict linear lines

nepotistic

matrilineal lines of dominance

low within group competition does what to females?

makes it tolerant and egalitarian

tolerant

less strict hierarchies and more tolerance to subordinates

egalitarian

prosocial behaviors are directed towards kin and non-kin

what does high between group competition do to females?

it will cause the larger groups to outcompete the smaller, cause them to work together to defend territory, and females will choose to stay in their natal groups

what is the limiting resource for males?

their access to females

based on the socioecological model, what causes low potential for 1 male, multi female groups?

distributed resources

based on the socioecological model, what causes high potential for 1 male, multi female groups?

clumped resources

what is the exception to the socioecological model?

the folivore paradox

• while they eat dispersed resources and have a lot of predators, they still normally live in very small groups

what are the limitations of the socioecological model?

does not account for social factors, infanticide, parental care, disease, how habitats are different, difference in cognition, and the complexity of gender roles

what is the difference between natural selection and sexual slection?

they both deal with variability and are hereditary, but sexual selection is a struggle for mates and reproduction, whereas natural selection is the struggle for existence and survival

what can traits do in sexual selection not found in natural selection

traits can evolve if they increase reproductive success, even at the cost of survival

• example: Irish elk antlers

what are the underlying principles in sexual selection?

differential investment and reproductive potential

differential investment

females tend to invest more in offspring (quality) and males tend to invest less (quantity)

reproductive potential

female reproduction is based on gestation and can limit the amount of children they can have, whereas males can still reproduce anytime

what are the four main ways male reproductive strategies?

1. compete with other males for mating opportunities

2. compete for fertilizations

3. compete for territory (indirect benefits)

4. invest in parental care (indirect benefits)

how do males compete with other males for mating?

strong selection for traits can help males win fights with other males, and can lead to greater sexual dimorphism, and fight for social status

how do males compete for fertilization

have larger testicles which can create more sperm (found in multi male and female groups)

what are female reproductive strategies?

choose the best quality mate and cryptic female choice

how do females choose the best quality mate?

they choose that mate that gives them a direct benefit (care and resources) and indirect benefits (good genes and sexy sons)

what is sexy sons?

females prefer an arbitary trait that provides no link to genes or health, but her sons will have it and her daughters will have a preference for it

sexually selected signals

traits that where you have to be in good condition or have good genes to exhibit such as sexual coloring

• however, good genes dont need to be high quality, just compatible and complementary

Major histocompatibility complex

rodents can use smell to discriminate and choose mates based on diversifying MHC of offspring

cryptic female choice

post copulatory mechanisms (aka choosing sperm)

• this is an evolved action

what is some evidence of female choosiness

females can still engage with middle/low ranking males and undermine the male hierarchy

selective sperm use in humans

IVF and follicular fluid that attracts specific sperm

infanticide

since lactation is longer than gestation and females have to wean an infant before being impregnated again, a new alpha male will kill the infants so that they can mate with the mother as quick as possible

infanticide accounts for what percentage of infant deaths?

62%

what are the mating systems?

promiscuity, polygamy, and monogamy

promiscuity

relationships between many

• bonobos

polygamy

is broken down into two groups

1. polygyny

2. polyandry

polygany

1 male and many females

• orangutans

polyandry

1 female and many males

• marmosets

monogamy

one on one action

• gibbons

alternative mating strategies example in orangutans

males have two distinct face morphologies that dictate their mating strategy (unflanged or flanged)

unflanged orangutans

prefer first time mothers and use the sneak and force method for mating

flanged orangutans

prefer experienced mothers, use the call and wait method, and father more offspring but experience more stress

same sex adaptive behavior in primates

is a mode of forming social bonds and strengthening them, which can help in parental care, infant rearing, and food

what are the two types of observed same sex behavior

g-g rubbing in bonobos and male cupping found in gelades

what are the primate developmental stages

1. infant

2. juvenile

3. adolescence

4. adult

infancy

from birth until weaning

• about 0-4.5 years in chimps

juvenile

weening to start of puberty

• about 4.5 years to 8-10 years in chimps

adolescence

puberty

• 8-10 to 12-15 years

adulthood

capable of reproduction

• 12 years old in females

• 15 years old in males

what are the theories for primates’ prolonged developmental periods?

physiological constraints, ecological risk, and needing to learn

physiological constraints theory

delayed maturation and reproduction is a result of larger bodies and brains

ecological risk hypothesis is

growth is slower because the babies dont forage enough or as efficiently

• explains the long juvenile period

• slow growth is the adaptive response to starvation and predation

needing to learn theory

young primates need to acquire a vast amount of both foraging and social skills

what is the key relationship in a young primates life?

the mother is needed in their life both for comfort, learning, and nourishment

how does stress affect mothering?

can cause them to abuse, reject, reduce contact, and reduce responding to the infant

what are the maternal styles?

high rate of rejection, protectiveness, laissez-faire, authoritative, neglecting

high rate of rejection maternal style

this is correlated with earlier independence

protectiveness maternal style

correlated with timidness in novel situations