Question

Does meiosis occur before or after fertilization?

Answer 1

Hint: Meiosis is a type of cell division where one cell divides to form four haploid daughter cells. It is also known as reductional division because the daughter cells get only half of the chromosomes of the parent cell. Through meiosis gametes or sex cells are produced. The sex cell maybe a sperm or an egg. The process of meiosis occurs in two stages namely meiosis I and meiosis II.

Complete solution:
Meiosis cell division is essential for all sexually reproducing animals to maintain the same number of chromosomes in the offspring as in the parents. During fertilization, two haploid cells fuse together to become a new zygote. If the number of chromosomes is not reduced to one in the gametes then there will be four copies of each gene in the offspring. This would lead to many genetic disorders and developmental defects.
Hence meiosis should occur before fertilization to maintain the number of chromosomes in the zygote and prevent chromosomal defects in the offspring.
In some organisms, polyploidy (many copies of the same gene) is common. Most of the angiosperms and aquatic plants are polyploid in nature. Polyploidy gives rise to bigger flowers and hence bigger fruits.

Note:
Meiosis occurs in two stages namely meiosis I and meiosis II. Each stage is divided into several sub phases. Meiosis I is divided into prophase I, metaphase I, anaphase I, telophase I and cytokinesis I. Similarly, meiosis II is divided into prophase II, metaphase II, anaphase II, telophase II and cytokinesis II. Meiosis I produces two haploid daughter cells and at the end of meiosis II four daughter cells are produced.