Developing Human, The

Human development begins at fertilization when a sperm fuses with an oocyte to form a single cell, the zygote . This highly specialized, totipotent cell (capable of giving rise to any cell type) marks the beginning of each of us…

Human development is a continuous process that begins when an oocyte (ovum) from a female is fertilized by a sperm (spermatozoon) from a male to form a single-celled zygote ( Fig. 1.1 ). Cell division, cell migration, programmed cell death…