Reproduction in animals · जंतुओं में जनन
A free Biology lesson for Class 8 children.
Sexual reproduction needs two parents. The male gamete is the sperm and the female gamete is the egg, or ovum.
The fusion of a sperm and an egg is fertilisation. It makes a zygote, which divides again and again to form an embryo.
In humans, frogs and fish, the embryo develops inside the egg or the mother. Animals that give birth to young ones are viviparous; those that lay eggs are oviparous.
In frogs, fertilisation happens outside the body, in water. In hens and humans it happens inside the body.
Some animals change form as they grow: a tadpole becomes a frog, a caterpillar becomes a butterfly. This is metamorphosis.
Asexual reproduction needs one parent: Amoeba splits in two by binary fission, and Hydra grows a bud that becomes a new Hydra.