Syngamy: Definition, Meaning, Types, Difference Between, Video

What Is Syngamy?

Fertilisation, otherwise known as syngamy, refers to a process of sexual reproduction wherein two gametes, the sperm and the egg cells, combine to form one zygote. Following the fusion, the development of a new individual ensues, and the combination of the genetic material from both parents occurs. Through syngamy, a continuation of the species happens in that it brings forth offspring that are genetically diverse.

The importance of syngamy rests in the fact that this process is part of any organism's life cycle. On one hand, it provides for a combination of genetic material to enhance variation and adaptation, while on the other, also serves as an inducer of the embryonic development process, which gives rise to the growth of a new individual.

Types Of Syngamy

Syngamy can be divided into three categories:

Isogamy

• Merging of gametes morphologically similar but may differ physiologically.

• Examples: Some species of algae and fungi.

Heterogamy

• Fusion of gametes that differ in size or form.

• Examples: Most animals and some plants have this type where the egg cells are larger in size and the corresponding sperm cells are smaller.

Oogamy

• A type of anisogamy where a large non-motile egg fuses with a small motile sperm.

• Examples: Very common in animals, most plants and protists.

Process Of Syngamy

The whole process of syngamy can be divided into four successive stages:

Pre-fertilisation Events

• Gametogenesis: Formation of male (sperm) and female (egg) gametes by meiosis.

Mechanism Of Fertilisation

• Gamete contact and recognition: Gametes recognise and attach.

• Gamete membrane fusion: Plasma membranes of the gametes fuse.

• Nuclear fusion or karyogamy: Gamete nuclei fuse to form a zygote.

Post-Fertilisation Events

• Zygote formation: The combined genetic material is then enclosed within a single cell.

• Early stages of zygote development: Cell division and differentiation mark the initiation of the zygote's development.

Importance Of Syngamy

The process of syngamy holds importance due to the following reasons:

Genetic Diversity

• Syngamy and genetic variation: The genetic material from two parents comes together to increase the resulting genetic diversity.

• Genetic diversity and its benefit for populations: A population's survival opportunities, and adaptability to changing environments, rise considerably.

Evolutionary Implications

Natural selection and adaptation based on genetic variation further evolution. Case studies of evolutionary adaptations try to include antibiotic resistance of bacteria and colouration patterns in animals.

Syngamy In Various Organisms

Syngamy in various organisms is given below:

Syngamy In Plants

• Fertilisation process in flowering plants: Pollen transfers sperm to the ovule.

• Double fertilisation in angiosperms: One sperm fertilises the egg; another fertilises the central cell to form the endosperm.

Syngamy In Animals

• Fertilisation in different animal phyla: Ranges from external—aquatic animals to internal—terrestrial animals.

• Internal vs. external fertilisation: Internal fertilisation gives more protection, and fertilisation happening externally mostly takes place in water.

Syngamy In Protists And Fungi

• Special mechanisms of syngamy in protists and fungi: Pluriform, mostly with complex life cycles and specialised fertilisation techniques.

Factors Affecting Syngamy

Syngamy is affected by the following factors:

Environmental Factors

• Temperature, pH, and other abiotic factors: Environmental factors impact fertilisation.

Biological Factors

• Gamete compatibility and vitality: On this basis, the compatibility and vitality of gametes depend on the success of syngamy.

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