Pre-Fertilisation Events
Pre-fertilisation events are the processes that occur before the actual fusion of male and female gametes (fertilization) in sexual reproduction. These events ensure that the reproductive cells are ready and positioned for fertilization.
Pre-fertilisation involves two main processes:
- Gametogenesis: The formation of male and female gametes.
- Gamete Transfer: The transfer of male gametes to the site where the female gamete is located.
See in Fig
1. Gametogenesis
Gametogenesis is the process by which gametes (sex cells) are produced in the male and female reproductive organs through meiosis.
- Male Gametes (sperm in animals, pollen in plants) are produced in the testes or anthers.
- Female Gametes (egg or ovum in animals, ovules in plants) are produced in the ovaries or ovules.
In animals:
- Spermatogenesis: The process of sperm formation in males.
- Oogenesis: The process of egg formation in females.
In plants:
- Pollen grains (male gametophyte) are formed in the anther of the flower.
- Ovules (female gametophyte) are produced in the ovary of the flower.
2. Gamete Transfer
For fertilization to occur, the male gamete must reach the female gamete. This process varies between different organisms.
- In animals, sperm is usually transferred to the female reproductive system during copulation.
- In flowering plants, pollination is the process of transferring pollen from the anther (male part) to the stigma (female part). Pollination can be carried out by wind, water, or animals like insects.
After the pollen lands on the stigma, a pollen tube forms and grows down toward the ovule in the ovary, where fertilization can take place.
Example: Pollination in Plants
In flowering plants, pollination is the key event during the pre-fertilisation phase. For example:
- Self-Pollination: Pollen from the anther of a flower lands on the stigma of the same flower or another flower on the same plant.
- Cross-Pollination: Pollen is transferred from the anther of one plant to the stigma of another plant.
Pre-fertilisation Events in Flowering Plants
Let me create an image that shows the gametogenesis and gamete transfer in plants. The illustration will include a flower with its reproductive parts, showing the formation of pollen and ovules, as well as the process of pollination.
