Sexual Reproduction

Sexual reproduction

The reproduction that takes place with the fusion of male gamete and the female gamete is called sexual reproduction. Such reproduction usually occurs in animals and higher plant. Two parents male and female are involved in this process of sexual reproduction. In most of the animals, male and female are separate. Such animals are called uni-sexual. Man, birds, etc. in animals and papaya, pumpkin, etc. in plants are the examples of unisexual. In some animals, male reproductive organ and female reproductive organ are present in one animal. Such animals are called bisexual organisms. These organisms are also called hermaphrodite. Hydra, Earthworm. The mustard plant, etc. are the examples of bisexual organisms.

Sexual reproduction in plants

Reproduction takes place in the flowers of the plant. The male organ of flower is androecium and female organ of flower is gynoecium. Androecium produces pollen grains whereas gynoecium produces ova. Fusion of pollen grains and ova leads to fertilization. The zygote starts to form after fertilization.

Sexual reproduction in animals

There is no asexual reproduction in animals. After the sexual intercourse between male and female, the female is able to conceive the baby. After meiosis, the male reproductive system produces sperm (male gamete) and the female reproductive system produces an egg (female gamete). Then male releases its gamete that fuses with female gamete. The fusion may be internal (in higher organisms) or external (in lower organisms). If it is external then a medium, that carries male gamete, is required and mostly it is water. After fertilization, the egg becomes zygote and undergoes mitosis to become an embryo. Embryo again with the help of mitosis becomes a new individual.

In animals, there are two types of fertilization. They are:

1. External fertilization: Fertilization that takes place outside of the body is called external fertilization. Frogs and fishes do external fertilization.
2. Internal fertilization: Fertilization that takes place inside of the body is called internal fertilization. Most of the animals does internal fertilization. Example: Humans