Question

What is fertilization?

Answer 1

the action or process of fertilizing an egg or a female animal or plant, involving the fusion of male and female gametes to form a zygote is known as fertilization.

Answer 2

Answer:

Fertilisation : Events leading to coming together and fusion of two compatible gametes to form diploid zygote  is called fertilisation. The process of fusion of gametes is called syngamy. The two terms of syngamy and  fertilization are, however, often used interchangeably.

Depending upon the place of syngamy;

Fertilization is of two types: External and Internal.

• External Fertilization : It is syngamy that occurs outside the body of organisms. It usually takes place in  aquatic medium. External fertilization is common in most algae, some fungi, several invertebrates, bony fishes  and amphibians. The organisms performing external fertilization show great synchrony in the release of gametes  into the external medium for enhancing the chances of syngamy. Since it involves a chance factor, the number  of gametes of both the types is generally large. As a result, the number of offspring is also very high. They  are, however, extremely vulnerable to predators for their survival upto adulthood.  

• Internal Fertilization : It is syngamy or fertilization that occurs inside the body of the organisms. It is common  in terrestrial organisms but some aquatic and semiaquatic organisms also perform internal fertilization, e.g.,  fungi, reptiles, birds, mammals, sharks (cartilaginous fishes), bryophytes, pteridophytes, gymnosperms and  angiosperms. Egg remains in the body of the female. The male gamete reaches there to fertilize the same.  In animals and seedless embryophytes, the male gametes are motile. They swim up to the female gamete  to fertilize it. In seed plants, the male gametes are non-motile. They are carried to the female gamete by means  of pollen tube. Since internal fertilization is a sure method, the number of female gametes and hence the  number of offspring remains small.