ANATOMY

Detailed explanation-1: -The unfertilized egg is called a zygote.

Detailed explanation-2: -On the surface of every egg yolk there can be seen a tiny, whitish spot called the blastodisc. This contains a single female cell. If sperm is present when a yolk enters the infundibulum, a single sperm penetrates the blastodisc, fertilizing it and the blastodisc becomes a blastoderm.

Detailed explanation-3: -Did you know you can determine if an egg is fertile or not by looking at the germ spot? The germ spot is the white spot on the yolk. The non-fertile germ spot contains only the female’s cells and looks like a solid white spot. In a fertile egg the germ spot contains both the female and male cells.

Detailed explanation-4: -The blastodisc, also called the germinal disc, is the embryo-forming part on the yolk of the egg of an animal that undergoes discoidal meroblastic cleavage.