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2.E: Fertilization and Cortical Rotation (Exercises)

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  • At-home assignment

    Free response question:

    A recent paper examines the effect IVF may be playing on human evolution. Look at one or two of the traits being selected on by IVF (Table 1). and think about the role IVF might be playing in future evolution of that trait. Is the effect of IVF large enough to drive significant human evolution?

    Discussion Questions and Reading Guide

    The questions below were originally written for students reading Freaks Of Nature by Mark Blumberg and Endless Forms by Sean Carroll. However, the questions in bold are discussion questions that can be answered without these books.

    The "Reading Guide" questions are appropriate for short homework answers and the "Discussion Guide" questions are appropriate for open in-class or online discussion.

    Reading Guide for "Further Reading"

    1. What are the four major events of fertilization?
    2. What are the parts of an animal sperm cell?
    3. Where does the power for sperm propulsion come from?
    4. How does an animal egg differ from a sperm cell?
    5. What are the different layers of an egg cell?
    6. What is polyspermy? How does an urchin egg prevent this?
    7. What processes produce the first asymmetry in frog embryos?

    Discussion Questions

    1. What are some other mechanisms that reduce the rates of interspecific fertilization?
    2. What selective pressures drive pre-zygotic barriers between species?
    3. What is the significance of an egg packed with protein and mRNAs?
    4. What are different ways eggs and zygotes protect themselves in different environments? Consider, for example, urchin eggs, chicken eggs, and mammalian eggs.
    5. Why is it important for animal embryos to "break symmetry?
    6. What is the connection between eugenics and evolution?
    7. Why do we consider eugenics to be unethical?
    8. What does it mean when we say that cells "express" a gene?
    9. How are evolution and development linked as fields of study? What is the link between both and genetics?
    10. How are evolution and development both affected by environmental interactions?
    11. How does the Kirschner/Gerhart view of EvoDevo differ from the West-Eberhard view?

    Freaks Reading Guide: Chapter Two

    This chapter brings in the dimension of "time" into the picture. Two of the examples in this chapter are covered in this online text, Sonic Hedgehog and the Segmentation Cacade.

    1. What is cyclopia? Is it genetically or environmentally induced?
    2. What is induction and how does it relate to cyclopia?
    3. What is eugenics?
    4. What is the difference between teratogenesis and mutagenesis? Which of these are used by developmental biologists?
    5. How can the same mutation produce different phenotypes?
    6. What are the different types of twins?
    7. What subjects in this chapter are you interested in following up on later in the semester?