Transcript males - andreawise

Behavioral Biology
Chapter 52
Biology Raven and Johnson 7th Ed.
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Does the name Pavlov
ring a bell?
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Outline
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Behavioral Genetics
Learning
The Development of
Behavior
Animal Cognition
Migratory Behavior
Courtship
Communication in
Social Groups
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Behavioral Ecology
Foraging Behavior
Territorial Behavior
Reproductive
Strategies
Sexual Selection
Mating Systems
Altruism
Kin Selection
Social Systems
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Approaches to the Study of Behavior
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Behavior can be defined as the way an
organism responds to stimuli in its
environment.
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Behavioral Genetics
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Recent studies have shown identical human
twins, separated at birth, develop many
similarities, even though they were raised in
very different environments.
Behavior may be controlled by one, or many,
genes.
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Learning Influences Behavior
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Comparative psychologists focus on learning as the
major element that shapes behavior.
– nonassociative learning
 Animal is not required to form association
between a stimulus and a response.
examples
– habituation - decrease in response to a repeated
stimulus with no positive or negative
consequences
– sensitization - increased responsiveness to a
stimulus
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Learning
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Associative learning
– Association between two stimuli or between a
stimulus and a response.
Classical conditioning - Paired presentation of two
different stimuli creates an association between the
stimuli (Pavlovian conditioning).
Operant conditioning - Animal learns to associate its
behavioral response with a reward or punishment.
– trial and error
Skinner Box- mice learn to push a lever to release
food.
(They will push a lever to get cocaine and ignore
food, sex, and play, until they die.)
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Learning
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Instinct
– Investigations have shown some animals
have innate predispositions toward forming
certain associations.
 Learning preparedness demonstrates that
what an animal can learn is biologically
influenced.
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The Development of Behavior
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Parent-offspring interactions
– imprinting - social attachments to other
individuals that will influence behavior later
in life (Konrad Lorenz)
 sensitive phase or critical period
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Fig. 52.09
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The Development of Behavior
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Interaction between instinct and learning
– Genetic templates may guide young birds
to learn appropriate song.
 During critical period, the template will
accept the correct song as a model.
 Only the correct song can be learned,
but it still has to be practiced to be
sung correctly.
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Animal Cognition
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What does thinking mean?
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Animal Cognition
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Central question in animal behavior is
whether animals show cognitive behavior.
– Do they process information and respond
in a manner that suggests thinking ?
 Some examples are compelling:
 chimpanzees
 ravens
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Fig. 52.15
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Orientation and Migration
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Taxis - movement toward or away from a
stimulus
– positive (toward) and negative (away)
Kineses - increase in general activity level
due to increased stimulus intensity
Migrations - long-range, two-way
movements
– monarch butterflies
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Orientation and Migration
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Navigation
– navigation - ability to set or adjust a
bearing and follow it
– orientation - ability to follow a bearing
 Inexperienced starlings appear to
migrate by orientation, while older birds
use true navigation.
 magnetic field
 celestial clues
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Courtship
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Stimulus - response chain in which behavior
of one individual in turn releases behavior of
another individual
Courtship signaling
– Signals are often species-specific .
 Reciprocal responses provide a
continuous check on species identity.
 Stickleback- see next slide
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Stimulus-Response Chain
This ensures the right species is attracted, and also
increases the odds that the eggs will be fertilized.
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Courtship
Pheromones and acoustic signals
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Pheromones are chemical messengers used
for communication between individuals, and
often serve as sex attractants (
 Silk moths are the most famous example
 In humans egg and sperm—they are from
two individuals, right?).
 Also human behavior is affected by
pheromones.
Many insects, amphibians, and birds produce
species-specific acoustic signals to attract
mates.
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Communication in Social Groups
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Communicated information:
– alarm calls
– alarm pheromones
– trail pheromones
– dance language
 Waggle dance of European honeybee
relays direction and distance of a
located food source.
– primate vocalizations
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Waggle Dance of Honeybees
Angle indicates direction.
Tempo indicates distance.
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Territorial Behavior
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Territoriality is behavior in which individual
members of a species maintain exclusive
use of an area containing a limited resource.
– defense against intrusion
– made on cost:benefit basis centered
around fitness
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Competition for Space
6 bird
species
removed (R)
were
replaced by
existing
species and
by 4 new
species (N).
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Parental Investment and Mate Choice
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Mate choice occurs when individuals do not mate at
random, but appear to make decisions on mates
base on quality.
– common in females, usually they have a larger
reproductive investment
Parental investment refers to contributions each sex
makes in producing and rearing offspring.
– usually higher in females
– In mormon crickets, the male invests in a high
energy sperm, and the males are more selective.
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Reproductive Competition and Sexual Selection
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Sexual selection occurs when individuals
compete for mating opportunities.
– involves both intrasexual and intersexual
selection
– leads to evolution of secondary sexual
characteristics
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Products of Sexual Selection
In many species, the boys dress up for the girls : )
a. African paradise whydah
b. Peacock
c. Eyespots in Peacock/ Mates
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Reproductive Competition and Sexual Selection
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Intrasexual selection
– Individuals of one sex compete for the
opportunity to mate with individuals of the
other sex.
 Selection will strongly favor sexual
dimorphism.
– sperm competition
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Intersexual Selection
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Intersexual selection
– benefits of mate choice
 Males may help rear young, gather food,
defend nest, etc..
Indirect benefits
– Females may choose healthiest or oldest
males.
 overall genetic or physiological health
 more vigorous offspring
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Intersexual Selection
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Handicap hypothesis
 Only genetically-superior males can
survive with a handicap.
Sensory exploitation involves evolution in
males of an attractive signal that exploits
preexisting biases.
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Mating Systems
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Number of mates
– monogamy - one male and one female
– polygyny - one male and many females
– polyandry - one female and several males
Needs of offspring
– altricial - require extensive, prolonged care
(ex. Humans)
– precocial - require little parental care
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Mating Systems
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Extra-pair copulations -- (cheating)
– Researchers found that in one study, 20%
of red-winged blackbird offspring were a
result of extra-pair copulations.
 may be very pervasive
 Males benefit by increased mating
success.
 Females may benefit by increased
rearing assistance.
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Factors Favoring Altruism and Group Learning
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Altruism - performance of an action that
benefits another individual at a cost to the
actor (nest helpers)
– Natural selection would seem to argue
against altruism.
 Such acts may not be truly altruistic,
and may be benefiting the actor.
 Nest helpers may gain parenting
experience or inherit territory.
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Factors Favoring Altruism and Group Learning
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Reciprocity - Individuals may form partnerships in
which mutual exchanges of altruistic acts occur.
Ex: Vampire bats will share blood with those who
have shared with them in the past.
Kin selection - By directing aid toward close
genetic relatives, an altruist may increase
reproductive success of its relatives enough to
compensate for the reduction in its own fitness.
– The more closely related the individuals, the
more likely the potential genetic gain.
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Altruism
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Hamilton’s Rule- Altruistic acts (acts that
benefit another member of the same
species) are favored when rb > c
r = relatedness –proportion of shared alleles
b = benefit
c = cost
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Examples of Kin Selection
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Belding’s ground squirrel
– sound alarm calls when spot predators
 Females are more likely to call than males
because colony is mostly her relatives.
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Group Living - Evolution of Social Systems
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Society - group of organisms of the same
species organized in a cooperative manner
Insects
– All ants, some bees, some wasps, and all
termites are eusocial.
 Eusocial colonies are composed of
different castes of workers that differ in
size and morphology and have different
tasks to perform.
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Vertebrate Societies
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Vertebrate social groups are usually less
rigidly organized and cohesive.
– Some complex systems exhibit both
reciprocity and kin-selected altruism.
 also display higher levels of conflict and
aggression among group members
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Summary
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•
•
•
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Behavioral Genetics
Learning
The Development of
Behavior
Animal Cognition
Migratory Behavior
Courtship
Communication in
Social Groups
•
•
•
•
•
•
•
•
•
Behavioral Ecology
Foraging Behavior
Territorial Behavior
Reproductive
Strategies
Sexual Selection
Mating Systems
Altruism
Kin Selection
Social Systems
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