Reproduction in Organism

The biological property of living organisms continues their race by the mechanism of reproduction. Reproduction is a process by which living beings produce their future progeny and their kinds.  This process is very important in maintaining stability in the ecological community and for the extension of life on earth.

The reproduction is divided into the following two types:

1.     Asexual Reproduction
2.     Sexual Reproduction

The word “Reproduction’’ applies to production, and it is true that biological reproduction almost always produces an organism that is similar to the parent unit. Sexual reproduction, performed by the majority of the living organism, produces diversity.  Reproduction is required for the survival of species in dangerous changes in the environment. Reproduction is a fundamental feature of any organism. The process, whether sexual or asexual, conducts some a basic pattern:

1) They produce the progeny that is physicochemically and structurally the same as the parent.

2) The transmission of a hereditary pattern or code from the parent.

Asexual Reproduction

The creation of a new generation without the fusion of the gametes is known as asexual reproduction. With the help of Amitotic and mitotic division new progeny where is also called somatogenic or blastogenic reproduction. Asexual reproduction is usual in lower organisms such as lower plants and animals. Unicellular organisms example bacteria and protists and some plants, fungi and some animals can reproduce asexually.  Asexually reproduce the offspring by mitotic divisions that are identical to their parent- clones. Higher and multicellular organisms can produce through the cellular division from the somatic body cell. Many organisms can produce sexually and asexually. Asexually produce Organisms are living in a stable environment.

Asexual reproduction is divided into the following types:

Asexual reproduction by fission: Fission is the most widely arising in Protozoans and various Metazoans. fission divided into two types:

 Binary fission: The organism body divides into two equal and the same fraction are produced. It is most usual in protozoans but it also occurs in certain lower metazoans.

 Multiple fission: In multiple fission, the nucleus of the cell is divided into many nuclei. After the divide, Each daughter nuclei are surrounded by the little mass of cytoplasm and form the asexually reproducing body such as schizogonous, gamont, spores, etc.  Eg: Amoeba, plasmodium, Monocystis, etc

Asexual reproduction by budding or gemmation: in certain multicellular animals such as hydra and certain tunicates, the body gives out the small outgrowth known as the bud. E.g.: Hydra (coelenterate) etc.

Asexual reproduction by gemmule formation: In various metazoan organisms, are reproduced by performed peculiar Asexual bodies known as the gemmules and statoblasts. E.g.: FreshWater Sponge, Etc.

Asexual reproduction by regeneration: the regeneration is a process by which the organism develops or regenerates its lost or worm out part. E.g.: Protozoans, Sponge, Echinoderms Etc.

Sexual Reproduction

in sexual reproduction, the development of the new individual takes place by the fusion of the sex cells or male and female gametes. Sexual reproduction is the most common type of reproduction among plants and animals. Most of the higher and multicellular organisms reproduce sexually. The sexual reproduction process involves male and female gametes (sperm and eggs) are fuse together and form a zygote. This zygote is a unique and genetically-quite variant from the parent and introduces variation into a population. Sexual reproduction involves the following steps.

• The sexual reproduction Meiotic divisions in the germ cell produce haploid gametes (one set of chromosomes) usually ova (eggs) and sperm.

The ova and sperm fuse together and form a diploid (two sets of chromosomes) zygote (single cell).

This zygote then divides through the mitotic divisions to produce a large number of cells that differentiate to form the various types of tissues that make up the new individual.

It may be of the following types:

1. Syngamy: syngamy is the most common type of sexual reproduction in the plant and animals in syngamy the fusion of two gametes takes place completely and permanently
2. Autogamy: In autogamy, male and female gametes are produced by the same cell or organism, and both gametes fuse to form the zygote.
3. Exogamy: in exogamy, the male and female gametes are produced by different parents, and both unite to form a zygote.
4. Hologamy: in the lower organism, sometimes the entire mature organisms start to act as gametes and the fusion of such mature individuals is known as the hologamy
5. Paedogamy: Paedogamy is the sexual union of mutual fertilization of gametes that are produced immediately after the division of the adult parent cell by mitosis.
6. Merogamy: in merogamy the fusion of tiny sized and structurally different gametes takes place.
7. Isogamy: In isogamy, the fusion of morphologically and physiologically identical gametes takes place
8. Anisogamy: Some organisms produce two types of gametes. These two gametes are characterized by heterogamous gametes.  Both types of gametes are different from each other in their shape, size, and behavior and are collectively known as the anisogametes or heterogametic.  
9. Macrogamy: The syngamy or fusion of the macrogametes is known as macrogamy
10. Microgamy: Microgamy is common in certain protozoans, in micro gamy the fusion of microgametes takes place.

2). Conjugation: conjugation is the alternate fusion of the two organisms of the same species for a short period. Until both organisms change their genetic material. After exchanging the genetic information successfully both organisms are separated.

E.g.: Paramecium And Bacteria.

3). Automixis: when the mate’s nuclei of the same cell unit together to form new individuals this method is known as the Automixis.

4). Parthenogenesis: parthenogenesis is a special type of sexual reproduction. In parthenogenesis, the eggs of an organism develop into the young individual without the fertilization of eggs by the sperm.

E.g.: Rotifers, Wasps, etc.

Conclusion

This is the biological property of living organisms to continue their race by the mechanism of reproduction. Reproduction is required for the survival of species in dangerous changes in the environment. Many organisms can produce sexually and asexually. The aim of reproduction is It creates genetic diversity within a species in sexual reproduction and parents are producing genetically variant individual that is not similar to the parent. Some bacteria and other micro-organisms are produced asexually and resist their species from the extreme environment. Some Genetic variations can lead to evolutionary advancements that help the species to live in extreme environments and adapt to the new environment. Scientist show some experimental evidence that shows that sexual reproduction help to improve the health of an organism.