Transcript Animal Behavior

Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 43
Behavioral
Ecology
Lecture Outline
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Outline
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43.1 Inheritance Influences Behavior
43.2 The Environment Influences Behavior
43.3 Animal Communication
43.4 Behaviors That Increase Fitness
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43.1 Inheritance Influences
Behavior
• Behavior - any action that can be observed and
described
• Nature (inherited) versus nurture
(environmental) questions are still debated
 Genes influence development of neural and hormonal
mechanisms controlling behavior
 Today, most evidence points to the conclusion that
most behaviors have a genetic basis
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Inheritance Influences Behavior
• Experiments That Suggest that Behavior has a Genetic Basis
 Nest-Building Behavior in Lovebirds
• Fischers’s lovebirds and peach-faced lovebirds build nests and carry leaves
in different ways
• Hybrid offspring between these two species had difficulty carrying nesting
materials
 Food Choice in Garter Snakes
• Inland populations are aquatic and feed on frogs and fish while coastal
populations are terrestrial and feed primarily on slugs
– Inland populations refuse to consume slugs in the laboratory, however,
hybrid offspring between these two species accept slugs as a food
source
 Twin Studies in Humans
• Human twins separated at birth and raised under different environmental
conditions have been shown to have similar food preferences, activity
patterns, and select mates with similar characteristics
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Feeding Behavior in Garter Snakes
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inland
coastal
Inland garter snake does not eat slugs.
Percentage of Snakes
20
15
10
5
0
0.5
Coastal garter snake eats slugs.
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
Tongue Flicks per Minute
(Coastal): © John Sullivan/Monica Rua/Ribbitt Photography; (Inland): © R. Andrew Odum/Peter Arnold, Inc.
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Inheritance Influences Behavior
• Experiments That Suggest that Behavior has a
Genetic Basis (continued)
 Egg-Laying Behavior in Marine Snails
• Egg Laying Hormone in the marine snail Aplysia has been
isolated and demonstrated to control all of the components of
egg laying in this species
 Nurturing Behavior in Mice
• Maternal behavior in mice is dependent upon a single gene termed
fosB
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Maternal Care in Mice
Proportion of
Pups Retrieved
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0.8
fosB alleles
present
0.6
fosB alleles
not present
0.4
0.2
0
a.
b. fosB alleles present.
c. fosB alleles not present.
b,c: From J.R. Brown et al, "A defect in nurturing mice lacking . . . Gene for fosB" Cell v. 86, 1996 pp. 297-308, © Cell Press
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43.2 The Environment
Influences Behavior
• Fixed Action Patterns (FAP’s)
 Originally assumed to be elicited by a sign
stimulus
 Increasingly, scientists have found this
behavior to develop further after practice
• Learning
– A durable change in behavior brought about by
experience
– Ex: pecking behavior in laughing gulls
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The Environment Influences
Behavior
• Imprinting
 Imitation of behavior observed during
sensitive period
• Ex: Goslings follow any moving object after birth
• Sensitive period
– Period of time in which a particular behavior develops
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The Environment Influences
Behavior
• Social Interactions and Learning
 Avian brain is especially sensitive to
acoustical stimuli during a sensitive period
 Social experience appears to have an even
stronger influence over development of
singing
• Ex: white-crowned sparrow signing
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The Environment Influences
Behavior
• Associative Learning
 Any change in behavior that involves an
association between two events
• Examples of Associative Learning
 Classical conditioning
• The paired presentation of two different types of
stimuli causes an animal to form an association
between them
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The Environment Influences
Behavior
• Classical Conditioning
 The paired presentation of two different stimuli
causes an animal to form an association
between them
• Ex: Pavlov - dogs salivate when presented with
food.
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Classical Conditioning
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saliva at
sight of food
(unconditioned
response)
saliva at
sound of bell only
(conditioned response)
sound of bell
(conditioned
Stimulus)
food
(unconditioned
stimulus)
apparatus to
measure saliva
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The Environment Influences
Behavior
• Examples of Associative Learning
 Operant Conditioning
• Gradual strengthening of stimulus-response
connections
• Trick-training in animals
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The Environment Influences
Behavior
• Orientation and Migratory Behavior
 Orientation
• The ability to travel in a particular direction
– Many birds use the sun or star for cues
 Migration
• Long-distance travel from one location to another
– Ex: Starling migration
 Navigation
• The ability to change direction in response to
environmental cues
– Clues may come from the Earth’s magnetic field
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Starling Migratory Experiment
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Breeding
range
Wintering
range
Holland
Switzerland
Spain
typical migratory
route of starlings
experimental relocation
of all starlings
flight path of
experienced starlings
flight path of
inexperienced starlings
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The Environment Influences
Behavior
• Cognitive Learning
 Learning through observation, imitation, and
insight
 Insight learning
• Solving a problem without prior experience
– Animal appears to draw upon prior experience with other
circumstances to solve the problem
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Do Animals Have Emotions?
• Body language of animals can be
interpreted to suggest that they have
feelings
• Scientists believe that they have sufficient
data to suggest that many vertebrates have
feelings:
 Fear, joy, embarrassment, jealousy, love,
anger, sadness, fear
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43.3 Animal Communication
• Some animals are largely solitary and join
with a member of the opposite sex only to
reproduce.
• Others pair, bond, and cooperate in raising
offspring.
• Societies
 Members are organized in a cooperative
manner extending beyond sexual or parental
behavior
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Animal Communication
• Communicative Behavior
 Communication is an action by a sender that
influences the behavior of a receiver
• May be purposeful, but does not have to be
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Animal Communication
• Chemical Communication
–
Pheromones are chemical signals that are
passed between members of the same
species
» Some animals are capable of secreting
different pheromones, each with a different
meaning
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Animal Communication
• Auditory communication
 Faster than chemical communication
 Effective both day and night
 Can be modified by loudness, pattern,
repetition, and duration
 Language is the ultimate auditory
communication
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Animal Communication
• Visual communication
 Allows animals to signal others without
chemical or auditory messages
 Visual signals are most often used
• By species that are active during the day
• In contests between males who make use of threat
postures
• To establish dominance
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Male Baboon Displaying Full Threat
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Animal Communication
• Tactile Communication
 Occurs when one animal touches another
 Gull chicks peck at the parent’s beak in order
to induce the parent to feed them
 Foraging honeybees use tactile
communication to impart information about
the environment
• Honeybees return to the hive and perform a
waggle dance
• The dance indicates the distance and direction of a
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food source
43.4 Behaviors That Increase
Fitness
• Behavioral ecology
 Assumes that behavior is subject to natural
selection
 Behavior has a genetic basis
 Some behaviors lead to increased survival and
number of offspring
• Behaviors of animals we observe today has
adaptive value
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Behaviors That Increase Fitness
• Territoriality and Fitness
 Territoriality is protecting an area against other
individuals
• Male gibbons maintain their territory by singing and fight to
defend their territory
• Defending a territory costs energy
• Benefits of territoriality include a source of food, the right to
one or more females, a place to rear young, and a place
providing protection from predators
 Territoriality is more likely to occur during times of
reproduction
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Behaviors That Increase Fitness
• Foraging for Food
 Animals must acquire a food source that will provide
more energy than the effort of acquiring the food
 The optimal foraging model states that it is adaptive
for foraging behavior to be as energetically efficient as
possible
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Foraging for Food
Energy Gain (J/s)
6.0
6
5
4.0
4
3
2.0
2
1
0
0
10
20
30
40
Length of Mussel (mm)
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Number of Mussels Eaten per Day
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Behaviors That Increase Fitness
• Reproductive Strategies and Fitness
 Polygamous
• Males mate with multiple females
• Females invest more in the offspring
 Polyandrous
• One female mates with more than one male
• The environment cannot support several young
 Monogamous
• One male mates with one female
• Occurs when males have limited mating opportunities,
territoriality exists, and the male is certain the offspring are his
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Hamadryas Baboons
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© Thomas Dobner 2006/Alamy
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Behaviors That Increase Fitness
• Sexual Selection
 Adaptive changes in females and males that
lead to differential reproductive success
 Sexual selection often results in
• Female choice
• Male competition
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Sexual Selection in Male
Bowerbirds
• Male bowerbirds build a nest and attract a
female through visual and auditory courtship
behavior
 Displays are highly intense and aggressive
• Male displays that are too aggressive startle females and
may not be able to accurately assess male traits
 Studies demonstrate that females prefer intensely
displaying males as mates, and that successful males
modulate their intensity in response to female signals
• Thereby attracting females without threatening them
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Competition
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© D. Robert & Lorri Franz/Corbis
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Behaviors that Increase Fitness
• Societies and Fitness
 Living in a society has a greater reproductive benefit
than reproductive cost
• Benefits of group living include avoiding predators, rearing
offspring, and finding food more easily
• Group living can result in disputes over feeding places and
sleeping sites
 Dominance hierarchies are a way to apportion
resources
• Higher-ranking individuals have greater access to essential
resources
• Males and females may form separate dominance
hierarchies
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Behaviors That Increase Fitness
• Altruism Versus Self-Interest
 Altruism
• Behavior that involves a reduction in individual fitness
• Loss may be compensated by an increase in the fitness of
another member of the society
 Inclusive fitness includes
• Reproductive fitness of self, and
• Reproductive fitness of relatives
 Genetic relatedness may underlie many/most acts of
apparent altruism
 Reciprocal altruism occurs in groups of animals that
are mutually dependent
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The Queen Ant
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© Mark Moffett/Minden Pictures
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Inclusive Fitness
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© J & B Photo/Animals Animals/Earth Scenes
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