Chapter 1 Web links and web activities

History and basic concepts

The origins of developmental biology
Learn more about the early history of developmental biology at John Alroy’s History of Evolutionary Biology website. Construct an "intellectual family tree" that illustrates the people whose work influenced Wilhelm Roux during the late 1800s, when experimental embryology was first being developed as a science. In a brief essay, summarize the intellectual forces at work at the time, as represented by these individuals (see also Chapter 1 in Wolpert text). How did the work of Roux, and Driesch, set the stage for modern developmental biology?
Learn more about Wilhelm Roux at the above link.
Milestones in Development is a collaborative effort between five journals - NatureNature Cell BiologyNature Reviews GeneticsNature Reviews Molecular Cell Biology, and Nature Reviews Neuroscience. Click on 'Milestones' to view highlights of the discoveries that have made the greatest impact on the developmental biology field over the past 100 years, including Spemann and Mangold’s revelations on the organizing principles in the embryo (page 8 in Wolpert text).

The embryo contains a generative rather than a descriptive program

The genome does not provide a blueprint for the embryo, but rather contains a program of instructions for making the organism, just like origami instructions tell you how to fold the paper to make remarkably complex creatures.
At The Origami Embryo you can download directions for how to make your own embryo from a few sheets of endoderm, ectoderm and mesoderm (colored paper). Working through this project will help you to understand the four-dimensional changes that characterize a developing embryo (chicken), as it transforms with complex three-dimensional changes over time (the fourth dimension). This resource was developed by Kathryn W. Tosney at the University of Miami.

Patterning can involve the interpretation of positional information
Animations from FlyMove allow you to visualize what happens to a Drosophila embryo when you manipulate morphogen concentration to alter the patterning field. Click on “Processes” tab and select “Axis Specification and Gradients” (download Flash Shockwaves or QuickTime software, links provided). After performing these activities (and reviewing figure 1.27 in Wolpert text) answer the following questions:

  1. How does a morphogen control pattern formation and positional information in an embryo?
  2. What does threshold concentration of a morphogen mean for an embryo?