Differentiate between internal fertilisation and external fertilisation.

Soln:

Fertilisation, in general, is defined as the fusion of a male and a female gamete.

Internal fertilisation

It occurs inside the female body.

There are high chances of survival of the offspring.

Internal fertilisation protects the fertilised egg or embryo from harsh environments.

Examples are a cow, human, dog, monkey, etc.

External fertilisation

It occurs outside the female body.

There are low chances of survival of the offspring.

Most aquatic animals use this type of fertilisation, and the advantage of external fertilisation is that it produces a large number of offspring due to external hazards.

Examples are fish, frog, organisms etc.