What is Reproduction in Detail
There are two types of Reproduction which are as follows:
- Asexual Reproduction
- Sexual Reproduction
Asexual Reproduction
In asexual reproduction offspring is produced from body parts other than reproductive organs. It is seen in lower plants and animals. For example: Hydra.
Asexual reproduction is also defined as the type of reproduction in which only a single parent is involved. In asexual reproduction, sex cells (gametes) are not produced. No fusion of gametes takes place for the production of zygote or offsprings. It is only produced from the body parts.
Features of Asexual reproduction
The features of asexual reproduction are as follows –
- It is uniparental.
- The offspring produced by asexual reproduction is clone of parent. This means that it is exactly a carbon copy of the parent.
- It is a fast mode of reproduction.
Different forms of Asexual Reproduction are as follows:
Binary Fission
Binary Fission is a type of asexual reproduction in which parent cell splits into 2 daughter cells. Binary means two and fission means splitting. For example: Amoeba.
Amoeba is a single celled organisms that reproduces new individual of its type by dividing its nucleus into two nuclei.
After division of the nucleus, the body of amoeba divides into two parts with each individual part receiving a nucleus.
The two separate bodies of amoeba develop into new individuals.
This method of reproducing new individual by dividing into two individuals is called binary fission.
Steps involved in binary fission are as follows-
- The Amoeba first grows in size.
- Then its nuclear material doubles.
- Constriction appears.
- Followed by division of cytoplasm.
- Finally two daughter cells (offsprings) are formed.
Budding
In Budding, a new organism is produced as an outgrowth of the parent
body part. For example: Hydra.
Reproduction in hydra starts by the development of bulges called buds.
The buds are the small outgrowths from a parent hydra that develops into a new hydra.
As the new individual develops from buds the process of reproduction in hydra is called budding.
Spores are small, bulb like structures which develop at the top of the erect hyphae of the fungus plant. These spores are released into the air and germinate. These spores are also released into new individuals after landing into food or soil.
Fragmentation
It is the accidental process when the broken pieces of an organism (fragments) grows into a complete organism. For example: Fragmentation in spirogyra.
Regeneration
When the simple animals like Hydra, Planaria develop a new individual from their broken older part it is known as regeneration. It is carried out by specialized cells which grow large numbers of cells.
Sexual Reproduction
In sexual reproduction, offspring is produced due to involvement of two sexes and that is male and female. No two males or females can produce offspring. Only opposite sexes have capacity to produce offspring.
Reproduction takes place as a result of fusion between two gametes, one from each parent, it is called sexual reproduction.
This process of fusion between two gametes is called fertilization.
The formation of gametes involves exchange of chromosomal (genetic)
fragments between homologous chromosomes causing genetic
recombination which leads to variation.
Features of Sexual reproduction are as follows –
It is biparental
The offspring inherits some characters from parents and some new characters. The process of fusion between two gametes is known as fertilization. For example: If Father has blue eye, sometimes offspring also has blue eyes. This is due to inheritance of characters.
In this process of sexual reproduction, a male and a female gamete (reproductive cells) fuse to form a single cell called Zygote. This zygote gradually develops into an adult, similar to the parents. The individual that grows from a zygote, receives characters of both mother and father.