SEXUAL REPRODUCTION IN ANIMALS
It is the most common method of reproduction in higher animals. It involves the formation of male gamete from the male parent and female gamete from the female parent. In animals the male reproductive organ which produces the male gametes is testes, while the female reproductive organ which produces the female gamete is ovary. The male gamete produced by male parent in animals is called sperm. The sperm is a small cell having a pointed front end and long flagella (also called tail of the sperm). The function of flagella is to help the sperm in moving towards eggs. The sperms are produced in a large number from male parent. Most of the sperms get destroyed before reaching the eggs because they do not have stored food.
The female gamete produced by female parent in animals is called ovum or egg. It is round and large in shape as compared to sperms because a large amount of food is stored in it. It is non-motile because it does not possess flagella. A single egg is produced at a time.
Sperms are released by the male parent in the body of female parent during copulation. Inside the female parent’s body the sperm travels towards eggs and finally fuse with them to form zygote. The process of formation of zygote by fusion of male gamete with female gamete is called fertilization. The zygote then divides many times, to form a large number of cells and ultimately develops into a new baby.