The process by which two gametes (reproductive cells having a single, haploid set of chromosomes) fuse to become a zygote, which develops into a new organism. The resultant zygote is diploid (it has two sets of chromosomes). In cross-fertilization, the two gametes come from two different individual organisms. In self-fertilization, the gametes come from the same individual. Fertilization includes the union of the cytoplasm of the gametes (called plasmogamy) followed by the union of the nuclei of the two gametes (called karyogamy). Among many animals, such as mammals, fertilization occurs inside the body of the female. Among fish, eggs are fertilized in the water. Among plants, fertilization of eggs occurs within the reproductive structures of the parent plant, such as the ovules of gymnosperms and angiosperms. See Note at pollination.
The process of making soil more productive of plant growth, as by the addition of organic material or fertilizer.
[fur-tl-ahyz] 
tlˌaɪz