Developmental Mechanisms Problem Set

Problem 2: Events that occur during gastrulation

What DOES NOT normally happen during gastrulation?

A. Three embryonic germ layers are established

B. A cavity forms inside the developing embryo that will become the primitive gut

C. The embryo increases dramatically in size
During gastrulation, cells move to new positions and form the germ layers (ectoderm, mesoderm and endoderm) but the embryo does not increase in size. Growth occurs after gastrulation.

D. Embryonic germ layers begin to be committed toward distinct developmental fates

E. Cell migrations are a prominent feature of this developmental stage

The Biology Project Department of Biochemistry and Molecular Biophysics The University of Arizona Thursday, October 30, 1997
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