A zygote is the fertilized cell that will grow into a new animal or plant. When a female's ovum and a male's sperm cell join, the cell that results is called the zygote. The zygote then multiplies, and grows into an embryo. So, a zygote is formed from the union of two gametes, and is the first stage in a human organism's development. Zygotes are produced by fertilization between two haploid cells, the ovum and the sperm cells, which make a diploid cell. Diploid cells have copies of both parents' chromosomes and DNA. At conception it has all the necessary properties to create a fully formed human being. Life until death is a series of many different stages of development. 