Readings: Chapters 1-2 from “Endless Forms Most Beautiful”
With ideas you encounter in the reading, develop three discussion questions that integrate, explore, and extend what we have learned so far in the course about the mechanisms and principles of development. Access the link to the discussion question submission on the course schedule. If they are well thought out and complete they will earn you part of your credit for the homework assignment that day. We will select a couple of these to discuss in class (without associating names with who submitted them).
Reading Questions--bring your answers to these questions, as you will be responsible for answering one of them in class. You will not turn these answers in.
1. What are the 2 basic aspects of animal design? Give a human and Drosophila example of each.
2. What are serial homologs? Give an example from a vertebrate and an arthropod.
3. What is Williston’s law and how does it explain changes seen in the evolution of form? Give an example illustrating the law.
4. Where are the rules/directions/plans that control animal form? What experiments or data support this idea?
5. How can the study of animal “monsters”, like cyclopic sheep, provide insight into how animal form develops?
6. Each of the cells of an amphibian 2-cell stage embryo have the ability to form complete identical animal. This is not seen with the 2-cell stage C. elegans embryo. What do you think explains this difference?
7. What is the activity of the Spemann-Mangold “organizer” in controlling vertebrate body form (ie how does it impact the major body axes)?
8. When a ZPA is added to the wing bud (Fig 2.4) do the cells that compose the transplanted ZPA give rise to the extra digits or do the adjacent cells form the extra digits? What does this indicate about how the ZPA functions in cell fate specification?
9. How are organizers thought to function?
10. What is a homeotic transformation? Give an example of one.