Fertilisation is the process of combining male and female reproductive cells (sperm and egg) to initiate the development of a new individual.
Types of fertilisation:
1. External fertilisation: This occurs outside the body, typically in aqueous environments, such as in fish, amphibians, and many invertebrates. The sperm and egg are released into the surrounding environment, and fertilisation happens externally.
2. Internal fertilisation: This occurs inside the body, mainly in terrestrial vertebrates, including mammals, reptiles, and birds. The male deposits sperm inside the female's body, and fertilisation occurs within the female reproductive organs.
Stages of fertilisation:
1. Penetration: The sperm must reach and penetrate the protective layers surrounding the egg.
2. Activation: Once the sperm enters the egg, a series of chemical reactions occur to block the entry of other sperms and initiate the development of the fertilised egg.
3. Fusion: The genetic material from the sperm and egg fuse together, forming a single cell called a zygote.
4. Cleavage: The zygote undergoes rapid cell division to form a cluster of cells called a morula.
5. Implantation: The morula implants itself into the uterine wall to receive nourishment for further development.
Factors of fertilisation:
1. Timing: For fertilisation to occur, the sperm and egg must be released and available for fertilisation at the same time.
2. Fertility: Both the sperm and egg should be healthy and capable of fusion to successfully initiate fertilisation.
3. Sexual compatibility: Certain species require specific interactions between the sperm and egg that allow fertilisation to occur.
4. Environment: External fertilisation depends on environmental conditions, such as water pH, temperature, and other factors that can affect the survival of sperm and egg. Internal fertilisation requires a suitable environment within the female reproductive tract for successful fertilisation.
What is fertilisation?
Types of fertilisation?
Stages of fertilisation?
Factors of fertilisation?
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