Oviparous and Viviparous Animals: Science Cbse / Ncert Revision Notes
Based on the production of young ones, animals can be oviparous or viviparous animals.
- Oviparous animals are the animals which lay eggs.
- Viviparous animals are the animals which give birth to the young ones.
- External fertilisation is the process which involves the union of male and female gametes outside the body.
- Internal fertilisation is the process which involves the union of male and female gametes takes place inside the body.
Development in chick
- Hen is said to be oviparous as it lays the egg. But the fertilisation is internal.
- After fertilisation, the zygote undergoes rapid division and moves down the oviduct.
- As it travels down the oviduct, many protective layers form as a hard shell around the developing embryo.
- Egg contains only the embryo when laid by the hen. Hen sits on the egg to provide warmth necessary for the development of chick.
- The chick hatches from the egg after three weeks.