Chapter 35 : Animal Behavior

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Chapter 35 Animal Behavior
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Genetic Basis of Behavior

• The behavior of animals is any action that can be
  observed and described.
• All behavior has a genetic basis, as demonstrated
  by various experiments.
• Lovebirds are small green and pink African
  parrots several closely related species differ
  by the way they build nests.
• Hybrids between species have trouble with
  carrying nest materials.

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Nest-building behavior in lovebirds
SPECIES A
SPECIES B
Help ?
HYBRID
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• Several experiments have been done with the
  garter snake, which has two different populations
  in California.
• Inland populations are aquatic and feed
  underwater on frogs and fish.
• Coastal populations are terrestrial and feed
  mainly on slugs.
• In the lab, inland garter snakes refused to eat
  slugs but coastal snakes ate them.
• Hybrid offspring showed an intermediate
  acceptance of slugs as food.

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Feeding behavior in garter snakes
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• Both the nervous and endocrine (hormonal) systems
  are responsible for the integration of body
  systems.
• To test whether the endocrine system influenced
  behavior, the egg-laying behavior of a marine
  snail Aplysia was examined.
• Egg-laying hormone (ELH) causes the snails to lay
  eggs even without mating.
• ELH is thought to control the egg-laying behavior
  in Aplysia.

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Development of Behavior

• Some behaviors seem to be fixed action patterns
  (FAPs) in which a specific cue sets the behavior
  in motion.
• Experiments with laughing gull chicks show that
  improvement in motor skills, as well as visual
  experience, strongly affect development of chick
  begging behavior.
• This suggests that learning, rather than FAPs,
  may be involved in gull chicks.

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Pecking behavior in laughing gulls
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The Phenomenon of Learning

• Operant Conditioning and Imprinting
• A) Operant conditioning, one of many forms of
  learning, is the gradual strengthening of
  stimulus-response (behavior-reward) connections.
• B) Imprinting is another form of learning
  chicks, ducklings, and goslings will follow the
  first moving object they see during a sensitive
  period after hatching.

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Song-Learning in Birds

• Song learning in birds is an active area of
  research.
• White-crowned sparrows sing a species-specific
  song, but males of a particular region have their
  own dialect birds were caged into three groups
  to see how young birds learn to sing from older
  members of their species.
• Birds in the first group heard no singing when
  grown, these birds sang a song that was not fully
  developed.

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• Birds in the second group heard tapes of
  white-crowns singing when grown, they sang in a
  dialect, as long as the tapes had been played
  during a sensitive period.
• Birds in the third group were given an adult
  tutor these birds sang a song of even a
  different species, no matter when the tutoring
  began.
• It appears that social influence, along with
  genetics, is of great importance in the
  development of singing.

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Song-learning by white-crowned sparrows
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Adaptiveness of Behavior

• Since genes influence the development of
  behavior, it can be assumed that behavioral
  traits are among those subject to natural
  selection.
• Investigators studying survival value of a given
  behavior seek to discover how a given trait might
  improve reproductive success.

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• Males can father many offspring because they
  produce sperm in great quantity it would be
  expected that they inseminate as many females as
  possible.
• Females produce few eggs, so choice of mate
  becomes an important consideration.
• Experiments with satin bowerbirds and birds of
  paradise support these bases for sexual selection.

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Mating behavior in birds of paradise
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Female Choice

• Courtship displays are rituals that serve to
  prepare the sexes for mating they help male and
  female recognize each other so that mating will
  be successful.
• Courtship displays also play a role in a females
  choice of a mate.
• Female choice can explain why male birds are so
  much more showy than females colorful, lengthy
  plumes might signify health and vigor.

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Male Competition

• Evolution by sexual selection can occur either
  when females have the opportunity to select among
  potential mates, and/or when males compete among
  themselves for access to reproductive females.
• Only if the positive effects of male competition
  outweigh the negative effects will the animal
  have reproductive success.

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A male olive baboon displaying full threat
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Female choice and male dominance among baboons
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Territoriality

• A territory is an area that is defended against
  competitors.
• Territoriality includes the type of defensive
  behavior needed to defend a territory.
• Vocalization and displays, rather than outright
  fighting, may be sufficient to defend a
  territory.
• Red deer stags may actually lock antlers and push
  against each other to repel challengers.

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Competition between male red deer
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Animal Societies

• Some animals are solitary, others live in small
  groups, and still others organize a society in
  which members cooperate, a behavior extending
  beyond mating and parental care.
• Social behavior in societies requires
  communication between members.

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Communicative Behavior

• Communication is an action by a sender that
  affects the behavior of a receiver.
• Chemical communication uses chemical signals,
  such as pheromones an advantage is that this
  form of communication works both night and day.
• Auditory (sound) communication is fast and
  effective, and can be easily modified.

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Use of a pheromone
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A chimpanzee with a researcher
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• Visual communication involves signals used by
  species active during the day.
• For example, defense and courtship displays are
  exaggerated and are always performed in the same
  way so their meaning is clear.
• Tactile communication occurs when one animal
  touches another.
• Honeybees use a combination of methods of
  communication, but especially tactile ones, to
  impart information about food distance and
  direction.

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Communication among bees
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Altruism Versus Self-Interest

• Altruism is behavior that has the potential to
  decrease the lifetime reproductive success of the
  altruist (individual) while benefiting the
  reproductive success of another member of the
  group. At first this seems counterproductive!
• Genetic relatedness appears to underlie altruism
  an altruistic act is best targeted at a close
  relative sharing the same genes.

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Inclusive fitness
I Think That I Will Warn Everyone in the group,
not just my own