Download anim behav fall 02 - Faculty Web Sites at the University of Virginia

Field Trip to Ivy Creek Natural Area
•Tuesday, April 16
•Meet outside 130 auditorium in Gilmer at 7:00 a.m.
•Return: in time for 9:30 classes
•email me if you’re interested
Unit 5 Animal Behavior
Raven and Johnson 1999
Apr 10 W Substrates of behavior: genes, neurons &
hormones 925-937
Apr 12 F Circadian & circannual rhythms of behavior
937-945
Apr 15 M Mates, families and societies 950-958
Unit 6 Ecological Patterns and Processes
Apr 17 W Population structure and models of
population growth 959-965
Apr 19 F* Influence of density, disturbance &life
history on populations 965-973
Apr 22 M Biotic interactions and community structure
974-987
Apr 24 W Disturbance, succession and community
structure 987-990
Apr 26 F Historical and ecological biogeography
1007-1014
Apr 29 M Conservation and decline of biodiversity
1031-1044
Hormone-mediated timing of
reproductive behavior in Japanese
macaques
Animal Behavior
Behavior is the response of animal
to stimuli in its environment
response; muscular activities
(eg locomotion, singing), nonmuscular activities (eg
secretion of pheremone)…
Behaviors are biological traits not unlike physiological,
morphological traits
Most behavior is regarded as
adaptive
Behaviors are the
consequence of genetic
constitution and
environmental influences
Learning is a behavioral process;
Persistent adaptive behavior of an
individual that results from
experience
Intimidation display of frilled lizard makes it
look larger and more intimidating to
predator.
Evolutionary
foundation
Medical &
neurobiological
foundation
Darwin
1850
Broca
Morgan
Freud
Pavlov
1900
ETHOLOGY
COMPARATIVE
PSYCHOLOGY
NEUROBIOLOGY
Von Frisch
Lorenz
Tinbergen
1950
Sociobiology
Maynard Smith
1970
Contemporary
Synthesis
Konishi
Wilson
Nottebohm
Dawkins
Ecological, evolutionary
(ultimate focus)
Neural, ontogenetic, learning
and internal integration
(proximate focus)
Descent of behavioral
biology -- a subjective
impression of the history
and relationships of the
major disciplines
contributing to the
subject. (After Grier
1984)
Basic Mechanistic View of Behavior
External
environment
Stimulus
Indian tiger
investigates
chemical messages
left on tree by other
tigers
Receptor System
Internal Control System
Effector System
Proximate and ultimate causation? With wings folded back, kadydid
blends with background; when alarmed it stands on head and spreads
forewings, exposing brightly colored underface and startling its predator.
Automeris moth wing-flapping behavior
Proximate Causation; Genetic, developmental, neural, etc. processes activate
internal mechanisms that result in the behavior
Ultimate causation: moths’ response to potential predators affect reproductive
success; differential reproductive success, natural selection, drives evolution of
behavior
Behaviors are phenotypic traits; expression depends on genotype & the
environment in which the genotype is expressed.
Purves et al 2001
Each spider (Argiope aurantia)
performs a stereotypic, speciesspecific sequence of movements to
weave a web no prior experience or
opportunity for learning
Purves et al 2001
Japanese macaques living on an island learn, from
other members of the population, to wash sand off of
food found on the beach
Raven and Johnson 1999
Ethology
•discipline of animal behavior
originated in the 1930’s by scientists:
• trained in zoology and natural
history and evolution
•interested in how animals
behave under natural conditions
•studied proximate mechanisms,
addressed ultimate mechanisms
•much early work focused on stereotyped, species-specific behaviors
Karl von Frisch
Konrad Lorenz
Niko Tinbergen
Founders of ethology and pioneers of the study of
modern behavioral biology. Joint recipients of the
1973 Nobel Prize in Medicine or Physiology
•ethologists interpret behavior in an
evolutionary framework and focus on
the neural basis of behavior
•viewed behavior as largely
“innate”, or “instinctive”, ie,
genetically based (and subject
to natural selection)
•early ethologists developed
important concepts in behavioral
biology
A cuckoo hatchling removes
egg of host species -- a largely
“innate”or “instinctive”
behavior that is not learned.
Concepts of Classical Ethology
•Many species exhibit “innate” behaviors; stereotypical (relatively constant) behaviors that
manifest fully in form and function the first time they are performed, and are not learned.
•Innate behaviors are developmentally fixed all individuals exhibit virtually the same behavior
despite environmental differences within and outside their bodies during development and
throughout their life
•A Fixed Action Pattern is a highly stereotypical motor program triggered by a sign stimulus (a
“releaser” – often some feature of the same or another species). Innate releasing mechanism
is the nervous system component that provides instructions for the FAP, which usually
proceeds to completion even when releaser is removed.
•Concepts of “innateness” and “fixed actions patterns” are valuable, if not perhaps somewhat
overly simplistic (e.g. most innate behaviors do improve with performance, as animal learns to
execute them more efficiently
•Neuroethological research provides support for the
ethological concept of the innate releasing mechanism…
Egg retrieval behavior in Graylag Goose. A fixed action pattern
performed by female goose
Aggression in European Robin. Sign
stimulus is often a simple component
of the biologically relevant entity
The Neurobiological Basis of Behavior
Raven & Johnson 1999
Photoreceptors monitor prey motion (sign stimulus). Small
object (prey) whose image lies in center of ganglion cells
receptive field excites ganglion to generate action
potentials, transmitted to brain via optic nerve, where size
and movement of retinal image is processed and FAP
(tongue flick) is initiated
Keeton & Gould 1993
Toad responds to elongate stimulus moving lengthwise as shown;
completes the motor program without having “caught” anything. This
behavior is controlled by feature detectors in brain that respond
preferentially to elongate stimulus (middle row) moving into receptor field
Adaptive function of stereotypical,
“innate” behavior
FAP’s, triggered by simple cues do not require
extensive time otherwise required for neural
processing or integrating wide variety of inputs
Simple cue and relatively simple, stereotypical
behavior patterns are effective evolutionary
solutions to many situations in the lives of
animals, including humans.
Ultimate cause may be that for certain behaviors,
automatic and experience-independent modes of
expression may have maximized fitness to the
point that genes for variant behavior were lost.
Smiling appears spontaneously in human
infants at about four weeks. The innate nature
of this motor program is illustrated by the smile
of this eleven week old blind girl, whose eyes
are fixated on source of mother’s voice, a
complex behavior that is also innate. Smiling
helps cement a strong emotional attachment
between parent and child
Approaches to investigating how genes
affect behavior
•Hybridization
•Artificial selection and crossing of
selected strains
•Molecular analysis of genes and gene
products
Hybridization experiment with two species
lovebirds demonstrates 1) phenotypic
differences in behavior are based on different
genotypes, and 2) the behavior can be
modified by experience
Artificial selection and cross of
selected strains
Genes and hygenic behavior in
honeybees
•Uncommon instance in which behavioral
trait segregates in Mendellian fashion; most
behaviors are influenced by a wide array of
genes
•Some honeybee strains express a hygenic
behavior; they remove the carcasses of
dead larvae from their nests
•Adaptive function of behavior;confers
resistance to bacterium lethal to larvae
•Two apparent components to this behavior
•uncapping larval cell (u)
•removing carcass (r)
•Cross-breeding experiments with hygenic
and non-hygenic strains reveal
•simple Mendellian segregation of the
genes coding for each behavioral
component
•all F1 progeny are non-hygenic;
indicates each behavioral component
is controlled by a recessive allele
•back-crossing F1 with hygenic strain
produces 3:1 phenotype ratio expected for a
two-gene trait
Molecular genetics research reveals specific genes that influence behavior
•In Drosophila, male courtship
behavior is stereotypic,
species-specific, and requires
no learning
•Sexual differentiation is
controlled by a hierarchy of
genes, and in that hierarchy,
fru controls the branch that
leads to male courthship
behavior
Most elements of male courtship behavior are controlled by a
single gene
The fruitless gene controls male courtship in behavior in fruitflies
sex-determining pre-mRNAs are spliced in a specific
way in females and another way in males
female sxl
and tra
mRNAs
make
proteins
that control
splicing in
the
expression
of genes in
the
femalespecific
hierarchy
sex-lethal (sxl) is at the top of a gene hierarchy; it is expressed in
fly embryos with two x chromosomes (flies therefore destined to
be females).
Male sxl and
tra mRNAs
have stop
codons that
terminate
translation
the default
splicing of
dsx mRNAs
controls
male
anatomy
the default
splicing of
fru mRNAs
causes
formation of
nervous
system that
expresses
male
courtship
behavior
Behavioral ecology
Scope of the discipline of behavioral ecology
•Behavioral research is placed in an ecological context that emphasizes
evolutionary (ultimate) explanations.
•Investigations address the evolutionary significance of behavior, usually in
natural environments or experimental settings that simulate natural
environments.
Selection, fitness, and behavior
•Theory of evolution holds that organisms possess traits that maximize their
genetic contribution to subsequent generations
•We expect animals to have evolved behaviors that maximize their fitness
Behavioral ecology: Research on the
adaptive function of songbird repertoire
Observation: In some species of birds, males
have multiple vocalizations
Question: What is the adaptive function of a
“repertoire”; how is it that a repertoire
Hypothesis: Large repertoire conveys age and
experience to females, making males more
attractive mate
Prediction: Males with large repertoires will
acquire nest mates earlier than males with small
repertoires
Test (Comparative approach)
•Record vocalizations, in the field, of banded
males in a population in the weeks or
months prior to nesting (i.e. courtship
period)
•Analyze vocalizations with sonagraph; tally
number of different vocalizations for each
male
•Observe banded males and record date of
pairing for each
Results support hypothesis for sedge warblers; males with large repertoires attract
females to pair with them earlier in the breeding season. Further research showed that males
with large repertoires also acquired more breeding partners (the species is polygynous)
Learning: modification of behavior through experience
•Background
•Learning vs. maturation
•Habituation – a simple form of learning (independent study)
•Associative learning (independent study)
•Development of behavior (interactions of genes and learning)
•Parent-offspring interactions
•filial imprinting
•sexual imprinting
•Interactions between developmentally fixed motor programs and learning
•song development in birds
•Play (independent study)
Animal Cognition
•Cognitive ethology
•Internal representations and problem solving
•Movement
•kinesis and taxis; movement without cognitive maps (independent study)
•cognitive maps (spatial representations)
•migration
•piloting
•orientation
•navigation
•consciousness
Social Behavior and Sociobiology
•Interpretation of social behavior in an evolutionary framework
•Competitive social behaviors; contests for resources
Dominance hierarchy
territoriality
Mating behavior
courtship
mating systems
Inclusive fitness and altruistic behavior
Learning: modification of behavior through experience
•Background
•Learning vs. maturation
•Habituation – a simple form of learning (independent study)
•Associative learning
•Development of behavior (interactions of genes and learning)
•Parent-offspring interactions
•filial imprinting
•sexual imprinting
•Interactions between developmentally fixed motor programs and learning
•song development in birds
•Play (independent study)
Learning: modification of
behavior due to experience
Learning in the context of
genetic and environmental
components of behavior
•Many behaviors have a strong
environmental component, and some
behaviors may seem to be entirely due to
learning, but at some level, all behaviors
have a genetic component
Learning vs. maturation in
developmentally fixed behaviors
•Most developmentally fixed behaviors
improve with performance as the animal
learns to execute the behavior more
efficiently
•Modification of a developmentally fixed
behavior may be due to maturation
(ongoing developmental changes in
neuromuscular systems) in addition to or in
the absence of learning
Japanese macaque that has learned to wash
sand off of food before eating
Habituation
Solomon & Berg 1999
•Habituation is a simple
form of learning in which
responsiveness to a
stimulus is lost
•animal learns to ignore a
repeated, irrelevant
stimulus, which is
adaptive…
•fitness is probably
increased through
habituation, by allowing
animal’s nervous system to
focus on important stimuli
that signal food, mates, or
danger, instead of wasting
time or energy on barrage
of stimuli that are irrelevant
to its survival and
reproduction
After repeated safe encounters with vans transporting humans on
photo safari, many animals, including giraffes, zebras, lions, and
elephants, in the Serengeti learn to ignore them. Elephants typcially
ignore the vans unless the drive provokes them by moving too close.
In that event the elephant may challenge and even charge the van
Imprinting
Imprinting is learning that is limited to a
specific time in an animal’s life, the
critical period, and is generally
irreversible
Imprinting is a process by which social
attachments are made early in life that
will influence behavior later in life
•Filial imprinting; social
attachments form between parents
and offspring
•Sexual imprinting; attachment
forms by which an individual learns
to direct it sexual behavior at
members of its own species
Imprinted goslings following Mom
Imprinting in birds: mechanism and adaptive function
•In many bird species, young develop a strong behavioral bond with mother
•Bond forms through imprinting, during a critical period -- usually within a few hours of hatching
•Bond forms through vocal communication; older embryos in eggs can exchange calls with
nestmates and parents through eggshell; one or both parents usually present at hatching and
emitting calls
Raven & Johnson 1999
Lorenz investigated the
phenomenon of imprinting
•Newly hatched bird imprints on the
first moving object it sees (imprinting
stimulus) and then will direct their
social behavior toward that object
•Lorenz split a clutch of graylag goose
eggs; left half with mother to incubate
and raise; they showed normal
behavior, followed here, grew up to
interact and mate with conspecifics
•Half the clutch placed incubator,
offered himself as a model for
imprinting; goslings followed him as if
he were their parent; failed to
recognize mother or other conspecifics;
as adults, tended to develop social
relationships with humans, not geese;
some initiated courtship with humans
Lorenz being followed
by imprinted goslings
Ducklings will imprint
on the first object they
see, eg black box,
white sphere
Process of imprinting is genetically determined; but bird learns to respond to a
particular animal or object
The ability or tendency to respond to first object seen after hatching is “innate”
Fox 1995
Imprinting, critical periods, now
known to occur at various times in
the life of animals, not just in very
early stages
Imprinting was initially understood as a
learning phenomenon of very young
animals (e.g., Lorenz’ geese critical period
was first two days of life)
Current understanding is that similar
learning processes occur in older animals,
and involves a variety of functions
Aspects of imprinting in young falcons
Song development in birds: a study of
imprinting
Sonograms of songs of white-crowned
sparrows reared under three conditions
•Early experiments showed song
development in male white-crowned sparrows
is an imprinting phenomenon
•Two learning processes in the sparrow’s
song development
•bird must acquire a song type by
hearing an adult
•bird must learn to match this song
by listening to itself
•Later research showed variability in the
process
•Strong stimulus (exposure to live male
of another species) can overcome
developmentally fixed tendency to to
acquire only a conspecific song
•Same strong stimulus resulted in longer
critical period (>50 days)
Males that heard tapes of conspecific songs before
day 50 (a) learned to sing normally, months later.
Males raised ins soundproof chambers (b) learned
only to sing primitive template of song. Males
deafened after hearing tapes of conspecific song,
but before beginning to practice, did not even learn
the primitive template.
Endocrine control of
morphological and behavioral
basis of singing in male canaries
•Fernando Nottebohm ID’ed forebrain
nuclei responsible for song learning in
canaries
•High variation in size of nuclei among
males based on season and number of
vocalizations in repertoire; nuclei largest
during breeding season, in males with
most songs
•Reduction in nucleus size may be
mechanism for “erasing” unneeded songs
and regeneration, for learning of new
songs to take place
•One of the first demonstrations of growth
and development of neurons in adult
vertebrates
•Hierarchical processing of motor
program to vocalize is an important model
for understanding how humans speak
and learn to speak
Animal Cognition
Cognition
•Narrow sense: awareness,
consciousness
•Broad sense: ability of an
animal’s nervous system to
perceive, store, process and
use information gathered by
sensory receptors
Cognitive Ethology
•The study of animal
cognition; focuses on links
between behavioral output
and the internal data
processing by the nervous
system that gives rise to the
behavior
•One area of interest in
cognitive ethology is internal
representation of spatial
relationships in an animal’s
physical surroundings;
cognitive maps
Migration Feat: Monarch
butterflies of eastern North
America in a remote fir forest in
Mexico; the migration is over
3000 kilometers and takes from
two to five generations to
complete
Moving Somewhere: Travelling requires tracking stimuli in
the environment
•Taxis: Movement towards or away from a stimulus; specific orientation.
e.g. positive phototaxis of moths to outdoor light
•Kinesis: Random movement in response to stimulus
•Migration; regular movement, often circannual and two-way, over
relatively long distances; presumably requires cognitive mapping
•Piloting: ability to move from one familiar cue to another –
considered especially important in short-distance movements
•Orientation: ability to follow a bearing (compass sense)
•Navigation: ability to set or adjust bearing and then follow it
(compass sense and map sense); requires determination of present
location and compass direction
(Raven and Johnson 1999)
Starling Migration Displacement experiments indicate that
inexperienced starlings migrate by orientation (and is largely an “innate”
behavior) while older birds that have migrated previously use true
navigation (and modify their migration behavior through experience.
Purves et al 2001
dots
represent
pecks for
food
bird is
trained to
seek food
in the
south
bird with
6-hr phase
advanced
rhythm
now seeks
food in
east
A pigeon placed in a circular cage from which can see
the sky (not the horizon) can be trained to seek food in
one direction, even when its cage is rotated between
trials
Pigeon is placed on altered light-dark cycle
and its circadian rhythm is phase-advanced by
6 hrs. Bird is then returned to the training cage
under natural sky
Starlings and certain other birds have an “internal clock” they use to compensate for
the sun’s apparent movement through the sky
Cues used by Birds and Animals for Orientation and Navigation
Celestial Cues
•Sun is used commonly for diurnal migrants and stars are used commonly for
nocturnal migrants
•Indigo Buntings and other species are known to use the North Star for orienting;
compensation mechanism (clock) not needed because its apparent relative position
remains unchanged
•Birds that use sun and other stars to orient presumably have internal clocks that
allow them to compensate for apparent movement of sun or star due to rotation of
the earth.
Magnetic field
•Many migrating birds and other animals have the ability to detect the earth’s
magnetic field and to orient themselves with respect to it
•Generally, birds that
•Animals known or suspected to use Earth’s magnetic field to navigate include
honeybees, some fishes and amphibians and sea turtles
Magnetite, a
magnetized iron ore,
has been found in the
brains of some birds,
but the sensory
receptors birds use to
detect magnetic fields
have yet to be
identifieid
Orientation of homing pigeons is influenced by changes in magnetic field. Dots show
angles at which birds flew off. Direction of home is straight up. Birds tested for two magnetic
directions, neither of which affect birds on sunny days, but both do on overcast days,
suggesting a back-up system.
White-crowned sparrow
Swamp sparrow
Song Sparrow
(Optic tectum)
Midline Sagittal view of the brain of a rock dove
Sagittal section through the brain of a zebra finch, showing the
descending portion of the song system
Vocalizations: Songs and Calls
•Vocalizations -- inherited, learned, invented, or combination
•Most lineages have innate vocalizations
•For “learners”, inherited (innate) mechanisms guide learning
•Parrots, hummingbirds, most songbirds
•Well studied in species with fixed repertoires; among best
models of development of complex, learned motor skill
Critical Learning Period > Silent Period > Subsong Period > Song Crystallization
•“Storage period”; terminates when bird starts practicing by listening to itself
and matching some of its vocalizations to memorized syllables
Critical Learning Period > Silent Period > Subsong Period > Song Crystallization
•First Practice stage -- begins with unstructured syllables, ill-formed sounds
•Usually ends in a month or so, with a rudimentary mature song
Critical Learning Period > Silent Period > Subsong Period > Song Crystallization
•Rudimentary song is crystallized into real song
•Auditory feedback essential for song development; no songbird studied
produces normal song if deafened before crystallization, even after critical
learning period
•Deafening after song crystallization has no effect on song -- remains normal
Hormones and Behavior: Affect of
testosterone on brain growth and
development in birds
Animal Cognition -- outline
•Cognitive ethology
•Internal representations and problem solving
•Movement
•kinesis and taxis; movement without cognitive maps
•cognitive maps (spatial representations)
•migration
•piloting
•orientation
•navigation
•consciousness
Animal Cognition
•Cognitive ethology
•Internal representations and problem solving
•Movement
•kinesis and taxis; movement without cognitive maps
•cognitive maps (spatial representations)
•migration
•piloting
•orientation
•navigation
•consciousness
Social Behavior and Sociobiology
•Interpretation of social behavior in an evolutionary framework
•Competitive social behaviors; contests for resources
Dominance hierarchy
territoriality
Mating behavior
courtship
mating systems
Inclusive fitness and altruistic behavior
BIOLOGICAL
PATTERNS
AND
organism
PROCESSES
ACROSS
“LEVELS”
FROM
MOLECULES
TO
ECOSYSTEMS
MODERN UNDERSTANDING OF LEARNING AND
INSTINCTIVENESS:
Learning is possible only in boundaries set by instinct
•Now clear that some species have innate predisposition for
forming some associations, but not others.
•Innate programs have evolved because they foster adaptive
responses
Instinct and learning are interactive components of
behavior
Behavior An animal’s response to stimulus.
Behavioral Biology All-encompassing term for
Red spot on bill and shape of bill are the actual sign stimuli eliciting foodbegging response in nestling herring gulls
Tinbergen and colleagues found that a dot at the
end of the bill that contrasts in color with the bill
was the most effective releaser.
Comparative psychologists developed important concepts of learning
Principle research approach of comparative psychology involved controlled
experiments with models organisms -- mice, rats and other animals -- with
attributes that worked well in such experimental settings, with no
Associative Learning
•Classical Conditioning:
•Animal learns to associate a stimulus with a reward or punishment (eg Pavlovian
response)
•Reflex becomes associated with a new stimulus
•Operant Conditioning: Animal learns to associate one of its own behaviors with a
reward or punishment, then tends to repeat or avoid that behavior (e.g. Skinner box
experiments)
B. F. Skinner
Rat in Skinner box is
undergoing operant
conditioning
1
3
2
Associative learning (operant
conditioning) involving predatorprey interactions.
•Toad offered yellow and black bumble
bee takes it and is stung. Subsequently
refuses yellow and black insects
(Raven and Johnson 1999)
Classical Conditioning
Wildtype DNA
from fruit flies
can be take up in
plasmids, some of
which will then
carry the per+
allele. The
plasmids can then
be collected and
microinjected into
the embryos of
fruit flies with the
pero “restoring”
normal activity
Biological Rhythms
•Life, lineages, evolved in 24-hour cycles of light and dark
•Across kingdoms, lineages have endogenous circadian rhythms of
activity -- eating, sleeping, motor patterns (e.g. treadmill)...
•Period = one cycle length
•Phase= point on the cycle
•Entrainment= resetting of clock, via environmental cue
Rhythm entrained
to a 24 hr. lightdark cycle
Rhythm is freerunning in
constant dark, with
period of less than
24 hours
A ten minute
exposure to light at
24 hour intervals
will phase shift
and entrain the
rhythm
Genetic cross in honey bees
demonstrates an uncommon
phenomenon; behavioral trait
whose expression is controlled
by a single gene.
Circadian clock in mammals is in the suprachiasmatic nuclei
Birds with fixed
repertoires learn songs in
four stages
Song development in Birds; an example of imprinting
1. Critical Learning Period
•Perceptual Stage:
Information is stored for use
in later stages of learning.
•Less than one year in most
species
2. Silent Period
•Syllables learned during
early critical learning period
are stored - no practice
3. Subsong Period
•Practice stage: analagous
to infant babbling
4. Song Crystallization
•Sensorimotor Phase:Final
practice stage where plastic
song is transformed to real
song
•Select syllables taken from
Critical Learning Period > Silent Period > Subsong Period > Song Crystallization
•Marsh wrens - first 2 months ; white-crowneds, 6 or more
•Period terminates with rise of testosterone levels in spring; castrated males learn
for up to 2 years (demonstrated in Chaffinches)
•High Vocal Center controls learning in Zebra Finches- nucleus accumulates
testosterone, which mediates timing and sexual basis of song learning
•HVC lesions in critical learning period permanently impair song learning; song
maintenance not affected in lesioned adults
•Isolation during critical learning; birds never develop normal song, but innate
template of song develops
Regions of the vertebrate brain
Evolution of vertebrate brain