Behavioral Biology

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Behavioral Biology

• AP Biology
• Chapter 51

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What is Behavior?

• What an animal does and how it does it.
• Includes observable actions as well as invisible
  non-motor mechanisms by which it occurs.
• Two types of questions in animal behavior study
• Mechanistic Questions concerned with
  environmental stimuli, and genetic/physiological
  mechanisms of the behavioral act.
• Ultimate questions What is the evolutionary
  significance of the behavior? Presumes the
  behavior enhances fitness in some way.

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Causes of Behavior

• Nature vs. Nurture
• What is the cause of behavior? Genes or
  environment?
• False debate
• NOT either/or
• Matter of degree BOTH genes AND environment
  determine behavior.

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Innate Behavior

• An innate behavior is one in which all
  individuals exhibit the same behavior despite any
  environmental differences.
• Often thought of as being attributed solely to
  genetics.
• One of the first types of innate behavior to be
  studied was called Fixed Action Pattern.

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Fixed Action Pattern (FAP)

• Sequence of behavioral acts that is essentially
  unchangeable and usually carried to completion
  once initiated.
• Triggered by an external sensory stimulus (sign
  stimulus)
• Often some feature of another species
• Example Moths
• Instantly fold wings and drop to ground
• Sign stimulus is ultrasonic sounds made by
  predatory bats.

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Fixed Action Pattern (FAP)

• Another Example
• Male 3-spined stickleback fish
• Attacks other males that invade his territory
• Stimulus is red belly of intruder
• NO attack will occur if intruder lacks red belly
• WILL attack a fake fish as long as it has a red
  belly.

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Fixed Action Pattern

• The stickleback example

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Fixed Action Pattern (FAP)

• Many animals tend to use a relatively limited bit
  of information and behave very stereotypically to
  that bit in many different situations.
• Humans are different tend to respond to an
  entire situation rather than just one cue.

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Fixed Action Pattern (FAP)

• Whats the advantage to such behavior?
• FAPs triggered by simple cues prevent an animal
  from wasting time processing a wide variety of
  inputs.
• Simple cues and a relatively simple behavior
  pattern usually work well in an animals normal
  world.

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Current Research Approach in Behavior

• Behavioral Ecology
• Based on the expectation that animals increase
  their fitness by displaying optimal behavior.
• Expectation is valid only because genes influence
  behavior.
• If it werent, behavior could not be subject to
  natural selection and could not evolve.

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Examples of Research in Behavioral Ecology -
Songbird Repertoires

• Why have a repertoire of songs instead of one
  really good song?
• Hypothesis a repertoire increases fitness
  because it makes an older, more experienced bird
  more attractive to females.
• For this hypothesis to be true,
• Males must learn more song types as they age.
• Females must prefer to mate with males having a
  large repertoire
• THESE ARE TWO TESTABLE PREDICTIONS

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Examples of Research in Behavioral Ecology -
Songbird Repertoires

• Testing the hypothesis
• Prediction 1
• Determine if there is a correlation between bird
  age and repertoire.
• Some songbirds show this pattern and some dont.
• Prediction 2
• Determine if whether females are more stimulated
  by a large repertoire than a small one.
• Play recordings of songs to females.
• Observe female posture.
• Work leads to Evolutionary Explanation
• Large repertoires result in females mating more
  often/earlier in season with experienced males.
• Experienced males give young a better chance to
  survive.

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Examples of Research in Behavioral Ecology -
Songbird Repertoires

• What happens if we do NOT use evolutionary
  principles in our research?
• Might record observations of various aspects of
  singing behavior.
• May produce interesting data, but will not
  EXPLAIN the behavior.

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• Foraging feeding behavior
• Favorite research topic
• What determines foraging behavior?
• Morphological traits
• Suspension feeding vs. predation
• Ecological and Evolutionary factors
• Behaviors caused by competition with others
• Behaviorists use this idea and analyze behavior
  in terms of cost/benefit

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• Types of foraging
• Generalists
• Feed on a wide variety of items
• Gulls feed on living/dead, aquatic/terrestrial,
  plant/animal
• Advantages have other options if one food
  becomes unavailable
• Disadvantages cant be terribly efficient at
  securing any one particular food.

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• Types of foraging
• Specialists
• Feed on very specific items
• Oystercatchers shore birds that are so
  specialized that they use individual hunting
  techniques learned from parents that further
  restrict their already specific shellfish diet.
• Advantages very efficient at foraging their
  specific food type.
• Disadvantages cant be very flexible if food
  source becomes limited.

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• More on Generalists
• Most do NOT choose food randomly.
• Concentrate on a particular item when it is
  abundant even to exclusion of other foods.
• SEARCH IMAGE set of key characteristics that
  will lead animal to desired object.
• Imagine looking for your biology book on a shelf.
  You dont read every title look for key
  physical characteristics first.
• If favored item becomes scarce, animal switches
  to new food source, develops new search image.
• Advantage Allows generalist to combine
• Efficient short term specialization
• Flexibility of generalization

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• Optimal foraging
• Natural selection will favor animals that
  maximize benefits vs. costs.
• Benefits calories gained Energy
• Costs
• Energy needed to locate, catch, eat food
• Risk of being caught by predator
• Time taken away from other activities search
  for a mate, for example

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• Example bluegill sunfish
• Feed on small crustaceans Daphnia
• Select large individuals supply most energy
• Smaller prey will be selected if larger is too
  far away

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Examples of Research in Behavioral Ecology
Cost/Benefit Analysis of Foraging Behavior

• Example bluegill sunfish
• Optimal foraging predicts that proportion of
  small to large prey eaten will vary with density
  of prey
• Low density bluegill will eat anything
• High density bluegill will eat mostly big
  Daphnia
• Experiments show that bluegills do this, but not
  to the extent that is predicted
• Perhaps young are not as good at picking large
  Daphnia

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LEARNING

• Definition modification of behavior resulting
  from specific experiences.
• LEARNING vs. INNATE Behaviors not clear cut
• An animal does not need to witness (LEARN) an
  innate behavior in order to perform it (i.e.
  bluegill foraging)
• However, most innate behaviors improve with
  experience as animals learn how to carry them out
  more efficiently.
• Also, some behaviors that SEEM entirely learned
  (a language, for example) are really an inherent
  function of a complex brain in humans, learning
  a language is, in itself, an innate behavior.

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Learning vs. Maturation

• Learning may improve innate behaviors, but
  improvements in innate behaviors are not ALWAYS
  due to learning.
• Improvements to behaviors may simply be due to
  the development of the physical body - MATURATION

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Example of Maturation

• Birds learning to fly
• Birds appear to be learning to fly as they
  flutter about their nests
• Young birds placed in restrictive devices that
  prevented this practice flying still flew when
  the devices were removed at an appropriate age.
• Learning to fly does not happen mature
  muscles and neural connections are what is
  required for young birds to fly.

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Habituation

• A simple type of learning
• Loss of response to stimuli that convey little or
  no information.

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Habituation - Example

• Hydra
• Contract when touched
• Stops responding if disturbed repeatedly

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Habituation - Example

• Mammals and birds recognize alarm calls of other
  species
• Eventually stop responding if no attack occurs
• Cry wolf Effect

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Habituation

• How does this increase fitness?
• Allows nervous system to focus on stimuli that
  signal food, mates or real danger instead of
  wasting time or energy on irrelevant stimuli.

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Imprinting

• Definition learning that is limited to a
  specific time period in an animals life AND is
  irreversible.
• In this type of behavior, learning interacts
  closely with innate behavior.

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Imprinting - Example

• Ducks and Geese
• Mother-offspring bonding is important
• If bonding fails, parent will not care for infant
• Certain death to offspring
• Loss of reproductive fitness to parent
• Question How do young know whom to follow?

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Imprinting - Study

• Research of Konrad Lorenz
• Young reared by mother showed normal behavior
• Divided a clutch of goose egg
• Some left with mom
• Some placed in incubator
• Incubated eggs spent first few hours with
  research instead of mom
• From that point on, the followed the researcher
  instead of the mother goose or any other geese.
• As adults the birds continued to show preference
  for humans and sometimes initiated courtship
  behavior with humans.

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Imprinting

• Geese have no sense of I am a goose, you are a
  goose.
• Respond and identify with the first object they
  encounter that has certain simple characteristics

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Imprinting

• Innate behavior in imprinting is the
  ability/tendency to respond
• Outside world provides imprinting stimulus
  the thing to which the response will be directed

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Imprinting

• Critical Period
• Distinguishes imprinting
• Limited phase in individuals development when
  learning of particular behaviors can take place.
• NOT confined to young
• Just as baby birds must imprint on parents,
  parent birds must imprint on young.

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Associative Learning

• Definition ability of many animals to learn to
  associate one stimulus with another

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Associative Learning

• Classical Conditioning
• Ivan Pavlov
• Learning to associate an arbitrary stimulus with
  a reward or punishment
• Feeding of dogs associated with bell
• Ultimately, the bell alone caused salivation in
  the dogs.

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Associative Learning

• Operant conditioning
• Trial and Error Learning
• Animal learns to associate one of its own
  behaviors with a reward or punishment
• Then tends to repeat or avoid that behavior

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Associative Learning

• Operant Conditioning Example
• Predators learn to associate certain prey with
  painful experiences, then modify behavior.

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Associative Learning

• Operant Conditioning Research
• B.F. Skinner
• Rat placed in a box
• Levers in box release food
• Animal quickly learns to associate manipulation
  of lever with reward of food
• Basis for most animal training done by humans

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Why Play?

• Play behavior with no apparent external goal,
  but involves movements closely associated with
  goal-directed behavior.
• Playful stalking and attacking
• Behavior does not usually involve painful bites,
  but animals grab one another using movements
  similar to those used to capture and kill prey

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Why Play?

• Animals with a social lifestyle are the ones that
  most often engage in play
• Young Dolphins spend long periods away from
  mothers in juvenile groups
• Engage in a full range of social and sexual play
• Learning how to be adults

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Why Play?

• Play is potentially dangerous and costly
• Risks of play
• Juvenile velvet monkeys are often killed by
  baboons when playing in juvenile groups away
  from adults
• A study of ibex (wild goats) showed that play
  often resulted in kids sustaining limp producing
  injuries

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Why Play?

• Play is potentially dangerous and costly
• Costs of play
• Consumes energy

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Why Play?

• What is adaptive about such an apparently
  pointless behavior
• Practice Hypothesis
• Allows animals to perfect behaviors they will
  need.
• Supported by the fact that play is most often
  observed in young animals
• Exercise Hypothesis
• Play is adaptive because it keeps muscular and
  cardiovascular system in top condition.
• Predicts that young animals would play more
  because they do not exert themselves in useful
  activities.
• Trouble with these hypotheses
• Adults are also observed playing.

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ANIMAL COGNITION

• What does an animals brain DO with the info it
  obtains from the outside world?
• Cognition - Ability of an animals nervous system
  to perceive, store, process and use information
  gathered by sense organs

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ANIMAL COGNITION

• Cognitive ethology includes study of how
  animals process information at all levels
• Problem solving
• animal consciousness or awareness
• how animals make internal representations of
  their physical surroundings (how does a dogs
  brain work when he catches a Frisbee? How do
  animals know where they are and where theyre
  going?)

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ANIMAL COGNITION

• Problem solving
• Highly developed in some mammals
• Primates and dolphins especially
• Chimps placed in an area with banana high out of
  reach and boxes on the floor can figure out
  that if she stacks the boxes she can climb to get
  the banana.
• Some birds
• Crows, ravens and jays

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ANIMAL COGNITION

• Problem solving Ravens
• Food attached to string
• Individuals showed different ways of solving the
  problem
• This one pulled the string up with one foot and
  held it in place with the other.

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Animal Cognition Movement from place to place

• Cognitive maps
• Internal representations of spatial relationships
  among objects in their surroundings
• Central hypothesis of cognitive ethology is that
  animals use these maps

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Animal Cognition Movement from place to place

• Cognitive map Example
• Bees
• Form and use mental maps of their foraging areas

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Animal Cognition Movement from place to place

• The most simple types of animal movement do NOT
  require cognitive maps
• Kinesis
• Taxis

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Animal Cognition Movement from place to place

• Kinesis simple change in activity rate in
  response to a stimulus
• Pillbugs are more active in dry environments than
  wet ones.
• Idea is that slowing down in a favorable
  environment tends to keep the animals in the
  favorable environment.

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Animal Cognition Movement from place to place

• Taxis
• Automatic movement toward or away from some
  stimulus
• Example Trout
• Automatically orient themselves in upstream
  position so they arent swept away
• Example Fly larvae
• Move to dark after feeding
• Keeps them away from predators

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Animal Cognition Movement from place to place

• Migration
• Regular movement over relatively long distances.
• Most extensive studies of cognitive maps involve
  this behavior.
• Birds, whales, some butterflies, some fish.

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Animal Cognition Movement from place to place

• Golden Plovers
• Migrate 13,000 km
• From Arctic breeding grounds to southeast South
  America.
• Some even navigate to Hawaiian Islands VERY
  small islands in a VERY large ocean.

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Animal Cognition Movement from place to place

• Migration path of Golden-Plover

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Animal Cognition Movement from place to place

• 3 mechanisms used in migration
• Piloting
• Orientation
• Navigation

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Animal Cognition Movement from place to place -
Migration

• Piloting
• Animal moves from one familiar landmark to
  another until destination reached.
• Short-distance movements

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Animal Cognition Movement from place to place -
Migration

• Orientation
• Animal detects compass directions and travels in
  a particular straight line path for a certain
  distance or until destination is reached.

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Animal Cognition Movement from place to place -
Migration

• Navigation
• Animal determines present location relative to
  other locations in addition to detecting compass
  direction (orientation)

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Animal Cognition Movement from place to place -
Migration

• Experiment orientation vs. navigation
• Starlings
• Normal migration path Europe to England/Iceland
• Captured in Netherlands
• Transported to Switzerland and released
• Juveniles continued southwest track to Spain
  result of orientation.
• Adults who had flown the route before flew
  northwest NOT the typical flight direction, but
  correct to get them to wintering grounds
• Adults could determine where their original goal
  was relative to the site where they were
  transported.

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Animal Cognition Movement from place to place -
Migration
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Animal Cognition Movement from place to place -
Migration

• What cues are used for orientation and
  navigation?
• Combination of compass references calibrated
  against one another
• Earths magnetic field
• The sun
• The stars
• Remember that animals must also compensate for
  MOVEMENT of sun/stars during the day/year

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Animal Cognition Movement from place to place -
Migration

• Utilizing migration cues
• Indigo bunting
• Avoids need to have a timing mechanism to adjust
  for star movement by fixing on the North Star
  which moves very little.
• Same method used by ancient human navigators.

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Animal Cognition Movement from place to place -
Migration

• Utilizing migration cues
• Starlings
• Use internal clock to compensate for changes in
  position of the sun throughout the day
• Change their orientation steadily at a rate of 15
  degrees per hour.

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Animal Cognition Consciousness

• Are nonhuman animals consciously aware of
  themselves and of the world around them?
• Do animals feel pain or pleasure or sadness as
  we do?
• Is the study of consciousness (awareness) within
  the realm of science?
• Conscious awareness is known only to the
  individual that experiences it
• It is not associated with any observable
  behavioral or physiological change

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Animal Cognition - Consciousness

• Donald Griffin Princeton
• Conscious thinking is inherent and essential part
  of the behavior of many nonhuman animals
• Argues if other animals behave in ways we
  associate with consciousness in ourselves, then
  maybe it makes sense to assume they have the same
  underlying awareness.

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Animal Cognition - Consciousness

• Jane Goodall
• First to describe cognitive decision making in
  chimpanzees.
• Griffin argues that abilities like these extend
  to other animals as well
• Injury feigning strategy of ground nesting birds

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Animal Cognition - Consciousness

• Griffin argues that abilities like those found by
  Goodall in chimps extend to other animals as well
  
• Sites injury feigning strategy of ground nesting
  birds

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Animal Cognition - Consciousness

• Griffin sees consciousness as arising through
  normal processes of natural selection
• Like other animal functions there is a continuum
  of varying degrees of conscious behavior that
  extends back into evolutionary history.

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Animal Cognition - Consciousness

• Poles of the argument
• Some researchers say that since it is difficult
  to apply scientific rigor to concepts of
  consciousness, then we should assume that animals
  are not aware.
• No researcher would say that all animals behave
  in ways that indicate consciousness
• Many Intermediate positions
• Are differences between humans and other animals
  fundamental or merely differences in degree?

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SOCIAL BEHAVIOR

• Definition any kind of interaction between two
  or more animals, usually of the same species.
• Complexity of behavior increases dramatically
  when interactions between individuals are
  considered
• Aggression
• Courtship
• Cooperation
• Deception
• Like other behaviors, social behaviors have costs
  and benefits to those participating.

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SOCIAL BEHAVIOR

• Sociobiology
• Like other forms of behavioral study, this one
  also applies evolutionary theory as its
  foundation for the interpretation of behaviors
  this time, social ones.

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SOCIAL BEHAVIOR

• Members of a population have a common niche
  strong potential for conflict
• Sometimes social behavior can involve cooperation
• A group carries out an activity more efficiently
  than is possible for a single individual

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SOCIAL BEHAVIOR

• Still, even when a behavior SEEMS mutually
  beneficial, (i.e. mating) each participant
  usually acts in a way that will maximize its
  benefits even if this is at a cost to the other
  participant.
• It is in competitive social interactions where
  this selfish aspect of behavior is most obvious.

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Competitive Social Behaviors

• Agonistic behavior
• Consists of some contest involving both
  threatening and submissive behaviors.
• Determines which competitor gains access to some
  resource
• Food
• Mate

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Competitive Social Behaviors

• Agonistic behavior, cont.
• May involve tests of strength
• Most commonly involves threat displays
• Make competitors look large or fierce
• Exaggerated posturing and vocalizations
• Eventually one individual stops threatening
• Ends with a submissive display

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Competitive Social Behaviors

• Agonistic behaviors, cont.
• Ritual
• Much agonistic behavior is ritualized
• Symbolic activity that does no serious harm to
  either combatant.

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Competitive Social Behaviors

• Agonistic behavior, cont.
• Dogs and wolves show aggression by
• Baring teeth
• Erecting ears, tail, fur
• Standing upright
• Looking directly at opponent
• large and threatening
• Loser in the competition
• Sleeks its fur
• Tucks its tail
• Looks away
• Submissive (appeasement) display inhibits further
  aggression

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Competitive Social Behaviors

• Agonistic behavior, cont.
• Amount of ritualization depends on scarcity of
  resource
• Male ground squirrels will inflict serious injury
  when competing for sexually receptive females
• Females are receptive for only a few hours each
  year
• Males entire reproductive future may depend on
  his success on that one day.
• If injury is inflicted, natural selection favors
  tendency to end contest as soon as winner is
  established.
• Violent combat could also injure the victor
• Also, any future interaction between the same two
  animals is usually settled very quickly

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Competitive Social Behaviors

• Dominance Hierarchies
• Social groups maintained by agonistic behavior
• Chickens
• pecking order
• Alpha hen controls the others, often by threats
  rather than actual pecking
• Beta hen subdues all others except the alpha and
  so on

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Competitive Social Behaviors

• Dominance hierarchies, cont.
• Wolves
• Function in packs cooperation in killing large
  prey
• Dominance hierarchy among females
• Top female controls mating of others
• When food is abundant, top female allows others
  to mate
• When food is scarce she allows less mating by
  other females, thus making more food available
  for her own young.

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Competitive Social Behaviors

• Territoriality
• Territory an area that an individual defends.
  Usually excludes other members of its own
  species.
• Feeding
• Mating
• Rearing young
• Territories vary in size depending on species and
  purpose
• Mating vs. feeding

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Competitive Social Behaviors

• Territory in Gannets
• VERY small
• Nesting purposes
• Defend by calling and pecking at each other

84
Competitive Social Behaviors

• Territoriality, cont.
• Territory vs. Home Range
• Home range area in which an animal roams and is
  often not defended
• Territory is often much smaller than home range.
• Distinction is sometimes not easily made
• Squirrels have home ranges that overlap, but will
  defend PART of the home range (its territory)
  from others.

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Competitive Social Behaviors

• Ownership of territory is continually proclaimed
• Function of bird songs
• Bellowing of sea lions
• Squirrel chatter
• Some animals mark territory with scent
• Clearly marking territory helps avoid violent
  encounters with rivals

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Competitive Social Behaviors

• Defense is usually directed only at conspecifics
  (those of same species)
• Different species can live in same territory, but
  occupy different niche, so not a competitor.
• Conspecifics are the only competitors for mates.

87
Competitive Social Behaviors

• Advantages of dominance and territoriality for
  the species
• Stabilize density
• If resources were allocated evenly, the fair
  share that each got might not be enough for
  anyone.
• Dominance and territoriality mean that at least
  some individuals receive adequate resources.

88
Mating Behaviors

• Most animals conscious sense that reproduction is
  important
• animals of the same species are often viewed as
  threats/competitors.
• How then is reproduction accomplished?
• Potential partners often go through a complex
  courtship interaction before mating

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Courtship

• What is accomplished by courtship?
• Complex sequence of actions confirms
• Animals are of the same species
• Opposite sex
• Appropriate physiological condition
• Not threats to each other
• Drosophila display

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Courtship

• What is accomplished by courtship?
• In some species, courtship also allows a mate to
  be chosen from a number of candidates
• Females nearly always show greater discrimination
  than males.
• Females have more parental investment in
  offspring

91
Courtship

• What is parental investment
• Time and resources individual must expend to
  produce offspring
• Eggs are larger and more costly to produce than
  sperm in many species
• Placental mammals have less difference in gamete
  size, but females have large investment in
  carrying young before birth.\
• In most species, females are very choosy because
  picking a poor mate can be a costly mistake.

92
Courtship

• Parental investment
• Males tend to with as many females as possible
• Males compete with other males, often by trying
  to impress females.
• Leads to more intense courtship displays in males
  than females often ONLY males court.
• Secondary sex characteristics more pronounced in
  males
• Bright plumage or antlers (sexual selection)

93
Courtship

• When individuals (females) actively choose a mate
  it is called Assessment.
• Female assesses two major areas
• Female assesses potential for parental care if
  that is involved in rearing young
• Assessment of genetic quality of the mate most
  important aspect if mate is not to be involved in
  parental care.

94
Courtship

• Assessment choosing a mate competent in giving
  parental care
• Male common tern carries fish and displays them
  to potential mates as part of ritual.
• Male may begin to feed fish to the female
• This may indicate to her how good he will be at
  providing food to young.

95
Courtship

• Assessment genetic quality
• In many bird (and insect) species males display
  in a common area called a LEK.
• Females visit the lek and choose among the males.
• After mating there is no further contact.
• Females choose mates with the strongest
  indicators of good genes
• High fitness may be indicated by vigorous
  displays, showy plumage, etc.

96
Courtship

• Sage Grouse Lek

97
Mating Behaviors Mating Systems

• Promiscuous mating
• No strong pair bonds or lasting relationships

98
Mating Behaviors Mating Systems

• Types of longer term mating
• Monogamous one male mating with one female
• Polygamous an individual of one sex mating with
  several of the other.
• Usually single male to many females polygyny
• This can be explained in terms of parental
  investment
• Male invests only sperm, so can have many
  partners
• Female invests more in eggs and/or nutrition of
  embryo/offspring
• SOMETIMES females mate with many males
  polyandry

99
Mating Behaviors Mating Systems

• Two factors help determine the type of mating
  system in a species 1st factor
• Needs of young
• Young may need more care than a female (or male)
  can provide alone
• Thus, the male may ultimately leave MORE viable
  offspring if he helps care for just a few rather
  than creating lots of offspring that dont get
  the care they need.
• May explain why most birds are monogamous
• In precocious birds, young require less care and
  parents are less likely to be monogamous.
• In mammals, female provides milk and male has
  little to contribute. If he contributes
  protection, he can usually protect many females
  at once - HAREM
• Certainty of paternity

100
Mating Behaviors Mating Systems

• Two factors help determine the type of mating
  system in a species 2nd factor
• Certainty of Paternity
• Female KNOWS her genes are in the offspring
• But even in a monogamous relationship, male may
  not be 100 certain if offspring are his
  possess HIS GENETIC INVESTMENT.
• Certainty of paternity is pretty low in species
  that have internal fertilization time delay
  between fertilization and birth leaves room for
  doubt
• In such cases it is MORE likely that the female
  will care for young alone
• External fertilization increases male certainty
  that offspring are his
• Many fish and amphibians with external
  fertilization are as likely to have father care
  for offspring as mother.

101
Mating Behaviors Mating Systems

• Do NOT think that certainty of paternity means
  that animals are actually AWARE of such things
  when they are mating!!
• It is BENEFICIAL in terms of FITNESS for the male
  to ensure that HIS genes are passed on and NOT
  someone elses. THUS, behaviors that lead to
  that outcome are SELECTED FOR by the natural
  selection process.

102
COMMUNICATION

• Social behaviors depend on communication
• Communication is the foundation of many of the
  behaviors weve already discussed (mating, for
  example)

103
COMMUNICATION

• Displays
• Animals intentionally, though not necessarily
  consciously, transmit information through special
  behaviors
• Bird song
• This is my territory. Keep out!
• Tape recorded songs of another male in a male
  birds territory cause the bird to become highly
  agitated.
• Someone else is not only in his territory, but
  claims it for himself.

104
COMMUNICATION

• Why do communication systems evolve?
• Think fitness the fitness of the sender of the
  information is increased by the effect the
  message has on the receiver of the message.

105
COMMUNICATON

• Deceit
• Male and female Photinus fireflies find each
  other and mate when female gives off a
  characteristic pattern of flashes in response to
  a males flashes.
• Females of another firefly genus respond to these
  male Photinus flashes with the same flashing
  pattern
• When male finds her, she eats him.

106
COMMUNICATION

• Deceit
• Dominant male mammal assumes control of social
  group
• Kills young that are born too soon to be his
  offspring
• With no offspring, females ovulate sooner so the
  new dominant male can father their offspring

107
COMMUNICATION

• Sensory mode used in communication
• Related to animals lifestyle
• Birds
• Diurnal
• Mostly visual and auditory displays
• Mammals
• Most mammals are nocturnal
• Visual displays relatively useless
• Olfactory and auditory displays work better

108
COMMUNICATION

• Communication by odors requires emission of
  pheromones
• Chemical signals that cause a response in a
  conspecific
• Generally not detectable by a different species
• Mammals and insects
• Can be very powerful
• Female silkworms emit a pheromone that can be
  detected by males several km away.

109
COMMUNICATION

• Fire ants - Pheromones

110
COMMUNICATION

• Communication in a bee hive - pheromones
• One of the most complex communication systems
• Pheromones emitted by the queen and her daughters
  (workers) maintain the social order of the colony
• Males (drones) inside the hive are unaffected by
  the pheromone.
• Males outside the hive where they can mate with
  the queen can detect the pheromone.

111
COMMUNICATION

• Bee hives bees must convey locations of good
  food sources
• Dances

112
ALTRUISTIC BEHAVIOR

• Selfish social behaviors
• Benefit individual at expense of others
• Easy to see how selection would favor such
  behaviors
• How can we explain the evolution of altruism?
• Altruistic behavior behavior that reduces the
  fitness of the individual and increases the
  fitness of the recipient of the behavior.

113
ALTRUISTIC BEHAVIOR

• Examples
• Meerkats
• Ground squirrels alarm calls alert the group,
  but increases the risk of the one giving the
  alarm.
• Bees
• Workers are sterile
• Still work for the hive / queen
• Will even sting intruders, thus dying for the hive

114
ALTRUISTIC BEHAVIOR

• Examples
• Naked mole rats
• Highly social rodents
• Underground chambers
• Almost hairless and nearly blind
• Colonies of 75 250
• One reproducing female who mates with 1 3
  males.
• Rest of colony is nonreproductive females and
  males who forage for food and care for the queen,
  kings and dependent offspring.

115
Altruistic Behavior

• Naked mole rat

116
ALTRUISTIC BEHAVIOR

• What explains altruism?
• When parents sacrifice their personal welfare for
  offspring, it is still increasing their own
  fitness because survival of offspring gets genes
  to next generation.
• Does helping other close relatives have a similar
  result?
• Siblings share genes with parents and offspring.
• Maybe selection favors helping parents produce
  more siblings or helping siblings directly

117
ALTRUISTIC BEHAVIOR

• Inclusive fitness
• Selection can result in an animals increasing
  its genetic representation in the next generation
  by helping close relatives even beyond own
  offspring.
• Describes total effect an individual has on
  proliferating its genes by producing its own
  offspring AND by providing aid that enables other
  close relatives to increase production of their
  offspring.

118
ALTRUISTIC BEHAVIOR

• Coefficient of relatedness
• Describes the proportion of genes two individuals
  share because of common ancestors
• Would be higher for siblings than cousins
• Higher the coefficient of relatedness, the more
  likely an individual is to aid a relative.

119
ALTRUISTIC BEHAVIOR

• Kin selection
• Mechanism of increasing inclusive fitness
• Kin selection would be rare or nonexistent in non
  social species
• If you are sterile, it makes sense for you to
  sacrifice yourself for fertile members of your
  family. If the fertile members dont survive
  and reproduce, inclusive fitness of a sterile
  individual will be 0.

120
ALTRUISTIC BEHAVIOR

• What about altruistic behavior towards NON
  relatives?
• Such behavior can be adaptive if the aided
  individual returns the favor in the future
  reciprocal altruism
• Commonly evoked to explain human altruism
• Occurs only in social groups stable enough that
  individuals have many chances to exchange aid.