The fertilization process is the process where specialized sex cells, known as male and female gametes, combine to form a new cell, known as a zygote. The fertilized cell then develops into a new offspring with its own set of genetic material. The offspring’s genetic material combines genes from the two donors, and this leads to genetic variation, an important aspect of survival in a population.
Fertilization can occur through two mechanisms. The first one is external where eggs are fertilized outside the body, and the second mechanism is internal, with the eggs fertilized inside of the organism’s body. External fertilization mostly occurs in wet environments and requires the two organisms to discharge their gametes into their immediate environs. In internal fertilizations, the organisms have specialized body parts to safeguard the developing egg.
Although fertilization is necessary for organisms that reproduce sexually, some organisms do not need fertilization to reproduce. This is called asexual reproduction. In asexual reproduction, an organism reproduces by creating a clone of itself through mitosis, a cell division process, without the need for fertilization.
In bisexual organisms, sexual reproduction occurs when male and female gametes from a single organism fuse. This is known as self-fertilization and is common in many flowering plants, invertebrates and protozoans.