Gametes, zygotes, and blastomeres of the embryo are cells and must exhibit all of the functional characteristics of a cell in order to survive. In addition to all the requisite cell functions, gametes, zygotes, and blastomeres of the embryo face challenges posed by the developmental program that regulates these cells. Gametes, zygotes, and embryos contain adaptations that allow these specialized cells to meet and surmount the challenges posed by the developmental program. These developmental challenges are directed at the structure and function of these specialized cells, and consequently the adaptations act through specializations in the cytoskeleton.