About The Book
In the human reproductive process, two kinds of sex cells, or gametes (GAH-meetz), are involved. The male gamete, or sperm, and the female gamete, the egg or ovum, meet in the female’s reproductive system. When sperm fertilizes (meets) an egg, this fertilized egg is called a zygote (pronounced: ZYE-goat). Each step in a human’s development – from the creation of the brain and heart to the formation of the fingers and toes – is carefully regulated. This title discusses how the study of model organisms has aided our understanding of a human’s creation and what happens when something is altered during the normal course of events.