Question

Example of external fertilization is
A) Fish and frog
B) Frog and monkey
C) Dog an and goat
D) Goat and fish

Answer 1

Hint: Fertilization is the process by which eggs and sperms fuse to form the zygote. It is an important part of sexual reproduction. Fertilization can be internal or external. External fertilization takes place outside the body of animals in the medium in which the animals live.

Complete Solution:
External fertilization is when fertilization takes place outside the female body. It occurs in the medium in which the animals live like water. For external fertilization to take place, the medium has to be moist in nature to facilitate the movement of the sperms towards the egg.
Let us now explore the modes of fertilization in the following animals:
Fish: Fishes show external fertilization. The males and females release their gametes, that is sperms and eggs in the same region and at the same time. This is known as spawning. The sperms swim towards the eggs and fertilize it. Ambient temperature helps to trigger spawning.
Frogs: Frogs are amphibians that can live in water and also on the land. Fertilization is external in these animals. During the reproductive phase of their life cycle, the males and females congregate in an area near water. The females choose their mates by listening to calls of males. After a female chooses a mate, he jumps on to the back of the female and both release their gametes at the same time into the water. The eggs and sperms thus released fertilize externally.
The organisms that belong to class Mammalia undergo internal fertilization. During the mating season, a female and a male organism undergoes the process of sexual intercourse where the males insert the copulatory organ or penis into the female vagina and releases sperms. The sperms travel to the fallopian tube of the female reproductive tract and fertilize eggs present there.
Dogs, monkeys and goats undergo internal fertilization since they are mammals. That’s why the option b, c, and d are incorrect.

Therefore, the correct answer is option A) that is fish and frog are the examples of external fertilization.

Note:
In external fertilization, the male gametes produced in large quantities so that there are more chances for their mating with female gametes. This type of fertilization also results in greater genetic variation. The gametes are transported by wind and water during external fertilization. This can also lead to the wastage of a larger number of the eggs and also eggs have fewer chances of fertilization.