Animal behavior test #3

Ultimate causes

Evolutionary explanations for behavior; why the behavior evolved

Proximate causes

Mechanistic explanations; how behavior occurs (genes, hormones, neurons)

Four levels of analysis

Genetic-developmental; neuronal-hormonal; evolutionary history; adaptive value.

Genetic-developmental level

How genes and developmental processes shape behavior.

Neuronal-hormonal level

How hormones and nervous system influence behavior

Evolutionary history level

How a behavior evolved through ancestors.

Adaptive value level

How behavior increases survival or reproduction.

Causes of monogamy in prairie voles

High vasopressin receptor density (V1aR) in ventral pallidum.

Dialects in white-crowned sparrows

Regional song variations learned from local adults

Marler studies

Birds need exposure to conspecific song during a critical period.

Isolation studies

Birds raised without song develop abnormal songs.

Baptista & Petrinovich studies

Social interaction can override genetic song template.

Social experience

Tutors increase accurate song learning and dialect adoption.

Genetic differences in males vs females

Males usually sing and have larger song nuclei.

ZENK

Immediate early gene activated when hearing song.

RA

Nucleus involved in song production.

nXIIts

Motor neurons controlling the syrinx.

Syrinx

Vocal organ of birds

IMAN

Nucleus important for juvenile song learning.

HVC

Song learning and production center.

Leonardo & Konishi study

Individual HVC neurons fire for specific song syllables.

Individual neuron activation

Neurons respond to specific song notes.

Shared ancestor vs convergent evolution

Vocal learning evolved via convergent evolution in birds.

Vocal learning & brain activity

Song learning activates specialized forebrain nuclei.

Comparison of 3 species of birds

Songbirds, parrots, and hummingbirds independently evolved vocal learning.

Comparison of mammals to birds

Few mammals show vocal learning; birds have specialized nuclei.

Natural selection and learning songs

Songs evolve for communication efficiency and reproductive success.

Identity announcement hypothesis

Dialects signal group membership.

Mate attraction hypothesis

Females prefer local dialects.

Ultimate causes of learning dialects

Mate choice, territory defense, social cohesion.

Type matching

Male replies with same song as rival.

Repertoire matching

Male replies with a different shared song.

Unshared songs

Used for aggression or unfamiliar rivals.

Dialects and mating preference

Females prefer males who sing local dialect.

Male developmental history

Early nutrition and tutor quality affect adult song complexity.

Proximate causes of birdsong

Hormones, brain nuclei, learning, gene expression.

Ultimate causes of birdsong

Mate attraction, territory defense, species recognition.

Nature vs nurture

Behavior arises from both genetic and environmental influences.

Interactive theory of development

Behavior = gene × environment interaction.

Genotype

Genetic makeup.

Phenotype

Observable traits.

Microarray approach

Measures expression of thousands of genes at once.

Mendel's Law of Segregation

Alleles separate during gamete formation.

Mendel's Law of Independent Assortment

Genes are inherited independently.

Mendel's Law of Dominance

Dominant alleles mask recessive ones

Mendelian inheritance

Traits follow simple dominant/recessive patterns.

Alleles

Different forms of a gene.

Dominant

Expressed with one allele.

Recessive

Expressed with two alleles.

Tasters vs nontasters

PTC tasting is a Mendelian trait.

Non-mendelian inheritance

Traits that don't follow simple Mendelian rules.

Chromosomes

DNA structures containing genes.

Genes

DNA sequences encoding proteins.

DNA

Molecule carrying genetic information.

Mutation

Change in DNA sequence.

Role of mutations

Source of genetic variation.

Genetic drift

Random changes in gene frequencies.

Nonrandom mating

Mate choice based on phenotype.

Imprinting

Rapid learning in critical period.

Lorenz & greylag geese

Goslings imprint on first moving object.

Denenberg & Whimbey study

Maternal care influences emotional behavior.

Genetics and coastal garter snakes

Preference for slugs is inherited.

Artificial selection

Humans select traits to breed.

Developmental homeostasis

Ability to develop normally despite variation.

Polyphenisms

Multiple phenotypes from one genotype.

Developmental switch mechanisms

Environmental cues trigger different phenotypes.

Adaptive value of learning

Helps organisms adjust to environmental changes.

Spatial learning

Learning landmarks for navigation.

Brood parasites

Imprint on host species.

Operant conditioning

Learning via reinforcement or punishment.

Biases in learning

Organisms learn some associations more easily.

Ethology

Study of natural animal behavior.

Instinct

Innate, unlearned behavior.

Fixed Action Pattern

Stereotyped, automatic behavior triggered by stimulus.

Sign stimulus

Cue triggering FAP.

Supernormal stimulus

Exaggerated stimulus causing stronger response.

Innate releasing mechanism

Neural network linking stimulus to behavior.

Code breaking

One species exploits another's signals.

Noctuid moths A1 receptor

Detects faint bat sounds; directional.

Noctuid moths A2 receptor

Detects loud bat sounds; triggers evasive dive.

Action potential

Electrical signal in neuron.

Synapse

Gap between neurons.

Interneurons

Connect sensory and motor neurons.

Tiger moths

Use ultrasonic clicks to jam bat echolocation.

Migrating monarchs

Use sun compass + circadian clock.

Cricket int-1 sensory interneuron

Bat-detection neuron.

Mike May study

Hindlegs contain phonotaxis CPG.

Central Pattern Generator

Neural circuit producing rhythmic movements.

Midshipman fish

CPG produces courtship humming.

Stimulus filtering

Nervous system filters relevant stimuli.

Peripheral filtering

Filtering at sensory organs.

Central filtering

Filtering in the brain.

Cortical magnification

Enlarged cortex area for important senses.

Star-nosed mole

Huge tactile cortex.

Barrel cells in the rat

Represent whisker input.

Face Area

Specialized for face processing.

Greeble training

Brain plasticity in visual recognition.

Social brain hypothesis

Larger brains evolved for social complexity.

Spotted hyenas

Complex social groups.

Wasp face recognition

Specialized brain region for faces.