PSYCH 320 Midterm #1

evolution

change in genetic makeup of a pop over time

caused by:

• genetic drift

• gene flow

• natural selection (not purposeful)

genetic drift

allele frequencies in pop change over generations due to random chance

worse in smaller populations

2 types

• bottleneck event

• founder effect

bottleneck event

adverse event w only a few survivors changes the genetic makeup of population

• can cause genetic drift

founder effect

tiny group of pop breaks away to colonize new area

gene flow

caused by movements between populations

affects genetic makeup of next gen

natural selection

process where organism with traits that increase their fitness reproduce more and pass those traits down

Darwin’s theory of evolution by NS- 3 postulates

individuals vary (random mutations)

varying traits are heritable

survival and reproduction aren’t random

theory of use and disuse

said that use or disuse of a trait could cause the trait to be passed down, incorrect

traits acquired during one’s lifespan are not passed down via genes

appeal to nature fallacy

assuming that a trait is morally good because it is natural

methods in animal behavior

correlational (doesn’t show causation)

experimental

observational

observational

describing behavior and conditions which it occurs under

compare means to test for difference btw naturally occuring groups - aka p values (if that hoe is low reject that null)

ex: parental feeding

considered “natural experiment”

experimental

manipulate 1 variable and measure effect on another, need a control group

ex: simulating environments

natural experiment

form of observational method, 2 or more naturally occuring groups are compared

levels of analysis

why and how of behavior

ex: bird songs

• ultimate causes of behavior:

• proximate causes of behavior

ultimate causes of behavior

• pertain to adaptive value and evolutionary history (why it evolved, reasoning behind behavior)

• applicable over generationSSS

• help explains adaptive value of behaviors

proximate causes of behavior

• pertain to the mechanistic often physiological (how it works)

• applies to individuals

• help explains how behaviors are accomplished

vocal learning

auditory learning

imitation (vocal production learning)

songbird vocalizations

songs (learned)

• long, complex

• usually by males in breeding season

calls (not learned)

• short, simple

• by males and females throughout

white crowned sparrows

have regional dialect

those who heard song at 0-50 days (sensitive period) sang

those who heard 100-150 days sang isolated songs

bird must hear tutor song during SP to copy it well in adulthood

heterospecific song learning

baby birds who heard other species recordings at sensitive period

but if played both conspecific & heterospecific songs → birds will selectively choose the conspecific song to copy

learned behavior experiments

deprivation experiment:

• remove baby bird from natural social environment early → see what behavior develops

• proves which behavior is learned

normal white crowned sparrows

have sensitive period 0-50 day phase → plastic/matching song phase → adult song phase

if baby bird hears a ‘tutor’ during this phase it will sing normally as an adult

bird songs components

elements: individual notes

syllables: one or more elements put tg

phrases: repeated series of syllables

tested if whistle in white-crowned sparrow was a signal

exposed baby sparrows to artificial tutor songs w whistle, heterospecific whistle, and w/o whistle

found that: most birds start learned song w a whistle and imitated a whistle from songs that started w a whistle regardless of species

tested if song learning w & w/o seeing tutor bird

found that if show conspecific tutor is covered and heterospecific tutor is visible → young sparrow will sing heterospecific song

nature vs nuture

impossible argument, both influence each other, cannot have one without the other

deterministic fallacy

idea that influence of genes on behavior is fixed

Galton

started nature vs nurture debate

eugenics

said only heritable traits can make a good man → nature produces babies as they are

Hogben

wanted to end nature vs nurture debate

Waddington

came up with epigenetic landscape where genes help shape hills/valleys → ball represents developmental history of a trait → alternative pathways but its hard to switch

shows how environment influences the final path after genes have affect

Lorenz

theory of instinctive behavior → 2 kinds of behavior

• instinctive

• learned

instinctive behaviors don’t have to be present at birth but can mature over time w/o experience

animals will develop innate behaviors w/o influence

Lehrman

interactionism: development requires constant interaction btw gene and environment

Niko Tinbergen

had 4 questions:

• mechanism (Causation)

• adaptive (function)

• (development)/ontogeny

• (evolution)ary/phylogenetic history

mechanism

what genes explain/trigger a behavior

trait exists because of its underlying physiology

proximate

development/ontogeny

how does behavior change while learning and developing

explains behavior in an individual

trait exists because of environmental influence or inborn tendencies

proximate

evolutionary/phylogenetic history

what are phylogenetic relationships among species, how did behavior evolve

trait exists because it has been passed down from ancestors

ultimate

adaptive function

what is adaptive value of a trait acted on by NS, how behavior affects fitness

why some organisms w trait have higher or lower fitness

trait exists because it is adaptive

ultimate

peter marler

starting hypothesizing all the bird song learning

evelyn fox keller

the field of epigenetics is not new; it has been known for decades that there are "epigenetic" ways to pass traits to offspring

nature vs nurture debate is bs

the modern synthesis

union of theories about evolution by natural selection and inheritance of traits via genes in 1930s

= gregor mendel’s theory of inheritance + darwin’s theory of evolution

created by Theodosius Dobzhansky

Soha and Marler

showed that young white-crowned sparrows can learn to mimic sounds of heterospecifics

Kruuk

studied mobbing behavior in birds