Answer
The internal ear develops from surface ectoderm; the middle ear develops from pharyngeal pouches; however, a pharyngeal cleft gives rise to each external ear.
Work Step by Step
About 22 days after fertilization, the internal ears begin to form from thickened ectoderm. The middle ear develops from the first pharyngeal pouch which is an outgrowth of the primitive pharynx; this pharyngeal outgrowth is lined with endoderm. The source of the external ear is the first pharyngeal cleft which is a groove between the first and second branchial arches. The first branchial cleft is also lined with endoderm.
