Animal Behaviour: Psych'Biol' 3750

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Animal BehaviourPsych./Biol. 3750

• Lecture 5 September 18, 2009

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Modern Synthesis

• Behavioural Ecology plus
• More attention to species natural history
• More mechanism brought back in. (as in
  Tinbergens proximate questions)

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Corticosterone levels are higher in a year that
capelin arrived late
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Parental Behaviour of Common Murres

• Yearly differences in resources?
• changes in stress hormone levels1?
• changes in chick feeding rate2 (not related to
  paternity3)
• 1Doody 2008, 2Wilhelm 2008, 3Walsh 2006

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Chapter 2 Evolution

• Why did Darwin call it Natural Selection?

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Darwin

• Natural selection acts on behaviour, morphology
  and physiology

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Evolutionary terms

• Phenotype Observable characteristic
• Genotype genetic composition
• Allele gene variant

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Process of natural selection

• Variation in the trait
• Fitness consequences (competition and
  differential survival reproduction)
• A mode of inheritance (genes and)

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Example Raven flight speed

• Variation in phenotypic trait? Fig 26
• Variation associated with differential fitness?
  Fig 27
• Test genetic basis of variation? Fig 28

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Fig. 2.8
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What is an adaptation?

• Genetically-based alternative that produces the
  highest fitness

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Selection of

• Genes? (Dawkins)
• Traits? (no says Gould Leewontin)
• Individuals?
• Groups?

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How is selection work?

• increased numbers of individuals with the
  successful phenotypes
• Random mutations

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How is variation maintained?

• Conventional evolutionary theory
• Random mutations
• Environmental change

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How is variation maintained?

• Controversial other possibilities
• Stress-induced mutations
• Epigenetic changes

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Types of selection

• Directional selection
• Disruptive selection (Fig 2.9)
• BUT selection is more often stabilizing (keep
  what works)

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Guppies from high and low predation sites (Fig
2.13)

• Growth patterns (Fig 2.14 2.15)
• Male coloration (Fig 2.13)
• Anti-predator behavior (Fig 2.16 2.17, Table
  2.2)

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Table 2.2
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Conclusions from transplant

• Anti-predator behavior maintained by predation

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Is behaviour always adaptive?

• Egg dumping in wood ducks (Fig 2.18-2.21)

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Evolution of eusociality Fig2.222.23

• Eusociality
• Not all individuals reproduce
• Communal care of young
• When is it better to maximize indirect rather
  than direct fitness?