Post-Fertilization Events

Events in sexual reproduction after the formation of the zygote are called post-fertilization events.

The Zygote

In all sexually reproducing species, the creation of a diploid zygote is a crucial step. The zygote is created in the surrounding environment, often water, in species that undergo external fertilization. In contrast, the zygote is created within the organism’s body in animals that undergo internal fertilization.

The zygote’s future development is determined by the organism’s life cycle and the environmental factors it experiences. In the case of fungi and algae, the zygote forms a tough outer shell to defend itself from desiccation and injury. The zygote germinates after a period of hibernation. For organisms with a haplontic life cycle, meiosis produces haploid spores, which grow into haploid individuals.

The zygote is the crucial connection that promotes species continuation between organisms of one generation and the next. Every sexually reproducing organism, including humans, begins as a single cell called a zygote.

Embryogenesis

Embryogenesis is the process through which an embryo develops from a zygote. The zygote goes through mitosis and cell differentiation during development. While cell division increases the number of cells in the developing embryo, cell differentiation allows groupings of cells to undergo specific alterations in order to become specialized tissues and organs that eventually form an organism.

Animals can be classified as either oviparous or viviparous based on whether their zygotes develop outside or inside the female parent’s body. Oviparous animals, such as reptiles and birds, lay fertilized or unfertilized eggs covered by a hard shell in a safe environment. These eggs undergo incubation, and eventually, the young ones hatch out of the eggs.

On the contrary, viviparous animals, including most mammals, including humans, carry their young ones inside their bodies until they reach a certain stage of growth. Afterward, they give birth to their young ones. Due to proper embryonic care and protection, the survival rate of the offspring is higher in viviparous organisms.

Post-fertilization events are the processes that occur after the fusion of the male and female gametes during sexual reproduction. These post-fertilization events in flowering plants are crucial for the development of the zygote into a mature seed or fruit. Understanding post-fertilization events in flowering plants and humans helps in learning the processes of embryonic development, growth, and the factors influencing successful reproduction. In this article, we will cover the post-fertilization events in detail.