A fertilized egg goes through several stages of development but initially is called a zygote. The next stages of development are blastocyst, embryo and fetus. More »

Chicken eggs become fertilized when chickens mate and the rooster's sperm successfully comes into contact with the ovum released by the hen's ovary. After the ovum's release, the sperm have around a half an hour to ferti... More »

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When a rooster and hen mate, the semen is stored inside the oviduct and is used later to fertilize the egg before the shell forms around it. The semen can be used up to a month after storage. More »

According to the National Center for Biotechnology Information, only one sperm normally fuses with an egg because if more than one sperm fuses, through a process called polyspermy, development of the zygote usually stops... More »

The embryonic stages between conception and birth include the zygote, morula, blastocyst, embryo and fetus, states the American Pregnancy Association. The stage between conception and growth is the zygote, and upon cell ... More »

The three stages of prenatal development occur in the order of germinal stage, embryonic stage and fetal stage, according to About.com. The germinal stage lasts just two weeks. The embryonic stage lasts six weeks, and th... More »

The swordfish, or "Xiphias gladius," starts as an egg, hatches when the zygote reaches about 0.15 inches long and lives for about 9 years. Eggs are fertilized externally after females spawn anywhere from 1 to 29 million ... More »