NAU Biology BIO 372
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BIO372 : Behavior : Sexual Dimorphism : Lesson

Sexual Dimorphism: Lesson

Use the outline below to guide your study of the material in this lesson. The outline indicates those topics the instructor feels are most important for you to learn in the course. You should read all the pages assigned, open and study the links, and read the terms in the glossary.

I. Human mating preferences

  1. Observations

  2. Hypotheses

  3. Evidence

II. Sexual selection: Redwing blackbirds
[Female redwing]
[Male redwing]
FemaleMale

  1. Theory

  2. Observations of redwing blackbirds

  3. Hypotheses

  4. Evidence

III. Dispersal: ground squirrels

  1. Observations
    • Natal dispersal is sexually dimorphic: males move away but females stay home
    • Males mate at locations 10 times farther from home than females do
[Belding's ground squirrel in Oregon, Photo by Don Baccus]

  1. Hypotheses and evidence

    Hypothesis      Name      Evidence
    Physiological
    • Neuronal
    • Hormonal
    • Blood samples
    • Gonadectomy
    • Hormone suplements
    Trigger
    • Observations of agonistic behavior
    • Correlation with litter size
    • Correlation with weight
    Fitness
    • Food shortages
    • Nest burrows
    • Ectoparasites
    • Mate competition
    • Avoid incest
    • Diets
    • Burrow density
    • Flea and tick infestations
    • Male fighting
    • Kin matings avoided
    Evolutionary
    • Natal dispersal is a direct
        result of natural selection
    • Circumstantial evidence
IV. Alcohol

  1. Observations

  2. Hypotheses

  3. Evidence

When you have completed this lesson, go on to Review Questions


E-mail Professor Gaud at William.Gaud@nau.edu
or call (520) 523-7516


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