Fertilization is the process of fusion of two types of gametes (spermatozoan and ovum) so as to form a diploid zygote. In human beings, fertilization takes place mostly in the ampullary isthmus junction of the oviduct (Fallopian tube).The oocycte can live for 72 hours but can fertilized only during the first 24 hours of this period. Ovum takes 12-24 hours to reach the site of fertilization.
Functions of Fertilization
1. It restores the diploid number of chromosomes, characteristics of the species viz., 46 in human being.
2. Fertilization initiates cleavage.
3. Fertilization results in determination of sex in the embryo.
4. It introduces the centrioles which are lacking in the mature egg.
5. Fertilization membrane developed after the entry of the sperm prevents the entry of other sperms into the ovum.
6. It brings together the chromosomes and genes from two different lines of ancestry and results in new genetic recombination, which ensures improved adaptation to ever changing environment.