Fertilization is the biological process by which male and female gametes (sperm and egg cells, respectively) combine to form a zygote. This process is essential for sexual reproduction and can occur in various ways depending on the organism.
In animals, fertilization usually occurs internally (inside the female's body) or externally (outside the female's body, as in many fish and amphibians). The fusion of the sperm and egg results in the formation of a diploid cell, which contains genetic material from both parents. This zygote then undergoes cell division and development, eventually leading to the formation of a new organism.
In plants, fertilization involves the fusion of male gametes (found in pollen) with female gametes (found in ovules) within the ovary of the flower, leading to the development of seeds. The process is crucial for genetic diversity and the continuation of species.