Difference between Oviparity, Viviparity and Ovo-viviparity

Oviparity vs Viviparity vs  Ovo viviparity

Oviparity 

(Example: All birds, amphibians, most of the fishes and insects)

1. Female lay eggs

2. Fertilization may be external or internal

3. Egg is generally yolky and large sized.

4. Development occurs outside female.

5. Placenta is not formed.

 Viviparity 

(Example : Most of mammals)

1. Give birth to young ones.

2. Fertilization always internal.

3. Egg is small sized and generally non yolky.

4. Development occurs always inside female.

5. Placenta is formed.

 Ovo viviparity

(Example: Rattle Snake and Sharks)

     1. Birth to young ones.

     2. Fertilization always internal.

     3. Egg is large sized and yolky.

     4. Development occurs inside female.

     5. Placenta not formed.