Question

How does internal fertilization facilitate life on land?

Short answer

Internal fertilization is prominently seen in higher vertebrates like reptiles, mammals, and birds, where fertilization occurs inside the female reproductive tract. The sperm carries the male gamete swimming towards the ovum.

Internal fertilization helps in preventing the egg from drying. Thus, the nutrients are protected and preserved from harsh environmental conditions. This kind of fertilization facilitates higher fusion chances and increases the birth rate.

Step-by-step solution

Fertilization

Fertilization is the process in which the two haploid gametes fuse to form the embryo. There are two types, internal and external fertilization, of which external fertilization is where the fusion occurs in the outer environment, mostly in aquatic medium.

Internal fertilization

Internal fertilization is when the male spermatozoa are inserted into the female body and travels in the female reproductive tract to reach the egg. The egg is found inside the female, later laid as an egg or fully grown, and is possible in land animals.

Facilitation of life because of internal fertilization

Animals such as mammals exhibit internal fertilization in three methods in which the fertilized egg is either laid as an egg (oviparity), holding the egg till complete development (ovoviviparity), and live birth by the female (viviparity).

The eggs are placed in a well-protected cover and help them from dehydrating. The mother nourishes the eggs. Internal fertilization makes the fusion of gametes more efficient. The success rate of fertilization is high, and young ones are mostly protected from predators and harsh environments.