Need of reproduction
- Reproduction is essential for the continuation of species
- If there is no new individual is born but the death is continued ,You can imagine what will happen
- The Species which don’t reproduce may be perished in longer run
Modes Of Reproduction
There are two modes of reproduction
- Sexual Reprodution
- Asexual Reproduction
Sexual reproduction– is a mode of reproduction where fusion of two cells called gametes (Male and female) usually coming from two parents .
Example- Fish Frog Cow Dog Human etc.
Asexual Reproduction- Is a mode of reproduction which does not involve fusion of gametes or new individuals are produced from a single parent.
Example-amoeba ,Yeast Hydra
Sexual Reproduction in animals
- In animals some lays eggs and some give birth to young ones.
Example – In Butterfly ,the eggs are laid on the leaves.
From these eggs comes out caterpillar
After some time the caterpillar change into immobile pupa. The pupa changes into adult butterfly.
- The animals which lay eggs are called Oviparous animals.( Eg. Hen,Fro Butterfly Etc.)
- The animals which give birth to young ones are called Viviparous animals.(Human,Dog cat Etc.)
- Male gametes or sperms are produced in an organ called testes.
- Female gametes or egg or ovum are produced inside ovary.
If the two type of gametes present in single/same individual . These organism are called bisexual or hermaphrodite.
Example- Earthworm, Leeches
If the two type of gametes present in different individuals . These organism are called uni-sexual.
Example- Frogs ,Bids , Humans etc.
When the sperm(from male partner) and ovum(from female partner) fuse together,a new cell, called zygote is formed.
The process of fusion of male and female gametes (Sperm and Ovum/eggs) is called Fertilization.
There are two different ways of fertilization.
- External Fertilization
- Internal Fertilization
External Fertilization- When fusion of male and female gametes occur outside the body of female partner,the fertilization is called external fertilization.
Example- In Frog and fishes, The male and female partner release their gametes in water,and fertilization takes place in water.
Internal Fertilization-When the fertilization or fusion of gametes takes place inside the female body , the fertilization is called internal Fertilization
Examples- In Humans,Dogs,Cats, Hens etc.