Question

Describe the three stages of sexual reproduction and mention the major events in each of them.

Answer 1

Sexual reproduction is a natural way of reproduction in humans, animals and also in the majority of plants. Sexual reproduction can be divided into three stages which are pre-fertilization, fertilization, and post-fertilization. Pre-fertilization involves the gamete formation and gamete transfer. Gametes are haploid cells. Male gamete is called sperm, whereas female gamete is called ovum or egg. Female gamete is immobile so male gametes need to be transferred for fertilization. Fertilization is the stage where haploid male and female gametes meet and fuse together to form a zygote. This can occur either outside the body (external fertilization) or inside the body (internal fertilization). After fertilization, the zygote divides mitotically and develops as an embryo by the process called embryogenesis. During embryogenesis, cell differentiates and modify. Animals are classified into oviparous and viviparous based on whether the zygote develops outside or inside the body respectively. Dogs are an example of viviparous animals and chickens are an example of oviparous animals.