Welcome Back to IB 150

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Welcome Back to IB 150

• The End???

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Past Pandemics

• Influenza during WWI
• Black Plague in Europe
• Decimation of Native American Populations
  following European arrival

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What kinds of diseases are likely to cause a
future pandemic?

• Ebola and related diseases - hard to contract and
  act too quickly
• Better candidates - Influenza or SARS - rapidly
  evolving and highly contagious

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Lecture 40

• Know the six types of disease organisms
• Know the biological differences between them
• Understand that disease infection is the same as
  predation

• Understand the importance of transmission between
  hosts
• Understand the evolution of virulence
• Understand the factors that make infectious
  diseases important in the modern world

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Lecture 41

• Know the two types of sexual selection
• Know the difference between adaptive and
  nonadaptive types of mate choice
• Be able to identify the two types of adaptive
  mate choice

• By able to identify the two types of non-adaptive
  mate choice
• Understand why careful experiments are necessary
  to examine the origin of mate preferences
• Understand that mate choice does not imply an
  aesthetic or conscious choice

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Sexual Selection

• Darwins theory to explain traits that
• Differ between males and females
• Do not appear to benefit individual survival
• Are not required for reproduction and caring for
  young

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Two mechanisms for sexual selection

• 1)
• 2)

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Do Animals Choose Their Mates?

• Victorian science - didnt buy it
• Didnt believe that animals had an aesthetic
  sense
• Ability to prefer specific characteristics was
  limited to humans

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Another Problem

• Why would animals prefer one mate over another?
• What difference does it make?

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1960s

• Experiments with birds demonstrate that choice
  does occur
• Study of sexual selection is suddenly fashionable

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How do we test for existence of a mating
preference?
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Why Do Mating Preferences Exist?

• Adaptive Explanations - Mate Choice increases
  fitness of chooser
• Nonadaptive Explanations - Mate Choice is the
  byproduct of something else

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Adaptive Explanations

• Direct Benefits - Chooser gets something from
  mate
• Good Genes - Offspring get a genetic benefit

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Infection and Mate Choice?
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Nonadaptive Explanations

• Correlation between preference and trait -
  positive feedback
• Sensory Exploitation

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Swordtail Fish
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How Do We Test These Ideas?

• Distinguish between mate choice and competition
• Investigate the origin of a preference

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Lecture 41

• Know the two types of sexual selection
• Know the difference between adaptive and
  nonadaptive types of mate choice
• Be able to identify the two types of adaptive
  mate choice

• By able to identify the two types of non-adaptive
  mate choice
• Understand why careful experiments are necessary
  to examine the origin of mate preferences
• Understand that mate choice does not imply an
  aesthetic or conscious choice