An Evolutionary View of Behavior

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An Evolutionary View of Behavior

• Starr/Taggarts
• Biology
• The Unity and Diversity of Life, 9e
• Chapter 47

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Ethology vs. Behavioral Ecology

• Ethology the study of behavior
• Visible action
• Chemical signals
• Learning
• Behavioral ecology the study of behavior and
  evolution, in other words how does behavior
  increase fitness

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• One can look at populations and learn many things!

• Naked mole rats!

Fig. 47.22, p. 848
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Genes and Behavior

• Behavior is a combo of nature and nurture!
• Behavioral responses depend on
• Neural patterns
• Patterns are based on genes
• There may be a selective pressure on those genes

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Hormones and Behavior

• Recall that hormones are signaling
  molecules
• They can impact behavior
• Example of hormonal impact on behavior song
  system in male birds
• Change in photoperiod affects pineal gland
• Pineal reduces melatonin secretion
• Gonads release testosterone
• Testosterone activates singing behavior

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Sterotyped Behavior (innate)

• Characteristics
• Instinctive Behavior will display on first
  encounter with stimulus based on nervous system
  pathways
• Sign stimuli or an external sensory stimulus
  will trigger a fixed action pattern
• It is developmentally fixed sequence of acts
  that are unchangeable and are completed when
  started
• Fixed action patterns help in mating, predator
  evasion, energy conservation, food acquisition,
  and finding shelter

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Sterotyped behavior (innate)
Steps 1040

• Fixed action patterns are sequences of acts that
  are unchangeable and are completed when started
• Baby bird crying for food
• Moth folding its wings and dropping to ground at
  a bats ultrasonic cry

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Learned Behavior

• In learned behavior animals modifies behavior
  based on experience
• Vervet monkey alarm calls improve over time
• The capacity to learn is wired into an animals
  nervous system
• Wiring determines what an animal can learn

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Learned Behavior Examples

• Imprinting exposure to key stimuli during a
  sensitive period
• Maturation when a behavior onsets due to
  developmental progression
• flight

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The Adaptive Value of Behavior

• Reproductive success refers to the survival and
  production of offspring (fitness)
• Adaptive behaviors promote the propagation of an
  individuals genes
• Social behavior is based on communication signals
  and is cooperative
• Selfish behavior is when an individual acts to
  boost its own fitness
• Altruistic behavior is associated with decreasing
  individuals success but boosting groups success

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Altruistic behavior example Meercats
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Cost of Living in Social Groups

• Competition for food
• Competition for mate
• Spread of contagious disease and parasites
• Risk of being killed or exploited

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Communication Signals

• Communication signals are actions or cues that
  have a beneficial effect on the signaler and
  receiver during an exchange of information
• Pheromones are powerful!
• Composite signals can be chemical, acoustical,
  and visual

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Dances of Honeybees

• Tactile displays

LifeSci 52120
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Dominance Hierarchies

• Established by agonistic behavior which is a
  combo of both threatening and submissive displays
  that determine access to a resource
• Members of a group are ranked according to status
• Status can change over time

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Fig. 47.13, p. 841
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Fig. 47.19, p. 845
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Territoriality

• Territories are defended areas for feeding,
  mating, and rearing young
• Usually associated with males
• Rituals and dominance hierarchies reduce
  aggression

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Courtship

• Behavior leading to copulation.

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Fig. 47.11, p. 840
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Parenting

• Time and energy drain!
• Genes live on!

LifeSci 48745, 49017, 49176, 49361