Question

Differentiate between:
(a) External fertilisation internal fertilisation.
(b) Viviparous and oviparous organisms

Answer 1

(a) Following are the difference between External fertilisation and Internal fertilisation:

$$\begin{array}{cccc}& \text{External fertilisation}& & \text{Internal fertilisation}\\ \text{i.}& \text{It occurs outside the female body.}& i& \text{It occurs inside the female body.}\\ \text{ii.}& \text{A large number of male and female gametes are released into the surrounding medium (e.g., water) where fertilisation takes place.}& ii& \text{The male gametes are deposited in the body of the female where fertilisation takes place}\\ \text{iii.}& \text{As the gametes are released in the surrounding medium a large number of gametes are needed to ensure fertilisation.}& iii& \text{The male gamete is deposited in the female body directly so lesser number of gametes are required to ensure fertilisation.}\end{array}$$

(b) Following are the difference between Viviparous and Oviparous organisms:
$$\begin{array}{cccc}& \text{Viviparous}& & \text{Oviparous}\\ \text{i.}& \text{Viviparous organisms give birth to young ones.}& i& \text{Oviparous organisms lay eggs.}\\ \text{ii.}& \text{The fertilised egg (zygote) develops into a young one inside the body of the female organism.}& ii& \text{The fertilised eggs are covered by hard protective shells and laid in a safe place in the environment.}\\ \text{iii.}& \text{Examples include human beings, cats, dogs, lions, tigers, and so on.}& iii& \text{Examples of oviparous organisms are birds, fish, insects, reptiles, amphibians..}\end{array}$$