Question

Differentiate between the following:

External fertilisation and Internal fertilisation.

Differentiate between internal fertilisation and external fertilisation.

Give two important differences between external and internal fertilisation.

Answer 1

	External fertilisation	Internal fertilisation
1.	The fusion of sperm and egg occurs outside the female body in external fertilisation.	The fusion of sperm and egg occurs inside the female body in internal fertilisation.
2.	It needs water or else the gametes will dry out and die.	It does not need water.
3.	Wastage of gametes is higher.	Wastage of gametes is lower.
4.	Mostly frogs (amphibians) and fish show external fertilisation.	Primarily, reptiles, mammals, birds and insects show internal fertilisation.