Vertebrate gastrulation involves several different types of tissue movements.

http://faculty.virginia.edu/shook/
Ray Keller revolutionized our understanding of the tissue movements that occur during amphibian gastrulation through the use of microsurgical techniques. Visit Dave Shook’s web site at the Keller Lab at the University of Virginia to view a series of movies demonstrating the varied tissue movements. Based on these images and your textbook answer the following questions related to amphibian gastrulation.

• How does cell shape influence tissue movements?
• What tissue layers undergo convergent extension during amphibian gastrulation?
• Where does involution occur? And what cell shape contributions to this action?
• Distinguish between radial and medio-lateral intercalation.

http://depts.washington.edu/fishscop/
For fun, put on your 3-D glasses and visit Mark Cooper’s lab at the University of Washington for a tour of zebrafish gastrulation events.

http://mcb.berkeley.edu/labs/harland/peoplepages/JYL/JYL.html
Bottle cells, produced by apical constriction are a unique feature of the gastrulating frog embryo (Page 302 and Box 7B in Wolpert text). Visit Jen-Yi Lee’s page at the website for the Harland Lab at the University of California-Berkeley to answer the following questions about bottle cells:

• What types of filaments are responsible for constricting the cells at their apical surface?
• In your own words describe how changing the shape of a few cells in this way can alter the morphology of an entire sheet of cells.