Question

Why is meiosis called reduction division? Describe the various stages with relevant diagrams. Add note on the significance of meiosis.

Answer 1

Meiosis was first discovered and described in 1876 in sea urchin eggs by Oscar Hertwig, a German biologist. Meiosis is a type of cell division that occurs only in germ cells. It is used to form the gametes such as egg cells or sperm. Meiosis is divided into two types meiosis l and meiosis ll. These are then divided into karyokinesis and cytokinesis. It leads to the evolution of sexual reproduction in eukaryotes. Crossing over takes place in meiosis between each pair of homologous chromosomes.

Complete answer:
The number of chromosomes in the daughter cells is half that of the parent cell, this is the reason why meiosis is known as reductional division.
Significance of Meiosis is:
-Meiosis decreases the number of chromosomes to half in the daughter cells of the gamete forming cells. It helps in the maintenance of chromosome number constant for a species when a zygote is formed.
-Variations occur during meiotic division due to the crossing over between paternal and maternal chromosomes or during Prophase l of meiosis is crossing over between homologous pairs.
-The variation produced during meiotic division thus leads to evolution.

Additional information:
-Meiosis takes place in all plants and animals.
-In females, it takes place in cells called oocytes.
-Meiosis errors result in aneuploidy.
-Cytokinesis takes place in Telophase i and Telophase ii.

Note: Meiosis starts in interphase with a germ cell. In the process of meiosis, the chromosome number becomes half the normal in sex cells. The mixing of genetic material forms genetically unique gametes and each of them fuses with another unique gamete during the process of fertilization and forms a unique zygote of the upcoming generation. Haploid cells are produced in meiosis.