Types of Sexual Reproduction

Sexual Reproduction:

Reproduction which takes place by the union of two different gametes, ie.e, the male gamete, and the female gamete is known as sexual reproduction. The gametes are a special type of unicellular reproductive unit produced from the gamete mother cells inside a special structure called gametangium.

Gametes are haploid (n) in nature. The male body produces male gametes and the female body produces female gametes. After the union of male and female gametes, one diploid (2n) cell is formed which is called a zygote. The zygote formed by the process of conjunction is called zygospore and which is formed by the process of fertilization is called oospore. This zygote produces a new individual through the development process in the future.

Characteristics of Sexual Reproduction:

1. It is an improved process. This reproduction process takes place through the union of gametes.

2. During this reproduction two individuals are required, and those are united with each other.

3. Meiotic cell division takes place at any stage of this process.

4. Variation always appears in the offspring.

5. Due to the presence of variation which has a positive role in evolution.

6. Presence of distinct alternation of generation is the life cycle.

Types of Sexual Reproduction:

1. Conjugation: The process of fusion between the two isogametes or fusion between two iso gametangium of the same species is known as conjugation. Generally, the conjugation process is found in lower groups of plants and animals. It takes place between the cells of two sexually different plants and animals. In plants, the cells of two filaments that are in contact, form protrusions that lie opposite one another.

The protrusions finally produce a conjugation tube through which fusion of the connected cell contents takes place within one of the two conjugating cells. The fusion product of the conjugation is the zygospore. After a period of rest, the zygospore germinates into a new plant body.

Example: Spirogyra, Paramoecium (protozoa).

2. Syngamy: The process of fusion between two different male and female gametes where one is smaller and flagellated and the other is larger and non-flagellated is called syngamy. This type of sexual reproduction is found in higher groups of plants and animals. Sexual reproductive units, i.e, gametes are produced within the gametangium.