What is the significance of meiosis in sexual reproduction?

Meiosis is significant in sexual reproduction as it produces genetically diverse haploid gametes necessary for fertilisation.

Meiosis is a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell. This process is crucial in sexual reproduction as it produces the gametes - sperm in males and eggs in females - that are necessary for fertilisation. Each of these gametes is haploid, meaning they contain one set of chromosomes. When fertilisation occurs, the haploid sperm and egg combine to form a diploid zygote, which contains two sets of chromosomes - one from each parent.

The significance of meiosis in sexual reproduction is not just in the production of gametes, but also in the genetic diversity it introduces. During meiosis, homologous chromosomes pair up and exchange segments in a process called crossing over. This results in new combinations of genes, which increases genetic diversity. This genetic diversity is crucial for the survival and evolution of species, as it allows for adaptation to changing environments.

Furthermore, meiosis ensures the constant chromosome number from generation to generation. Without meiosis, the chromosome number would double with each generation, leading to an unsustainable increase. By halving the chromosome number in the gametes, meiosis ensures that the diploid number is restored upon fertilisation.

In addition, errors in meiosis can lead to genetic disorders. For example, if chromosomes fail to separate properly during meiosis, it can result in gametes with too many or too few chromosomes. When these gametes are involved in fertilisation, it can lead to offspring with genetic disorders such as Down syndrome.

In conclusion, meiosis plays a vital role in sexual reproduction. It not only produces the necessary gametes for fertilisation but also introduces genetic diversity, maintains the constant chromosome number, and can lead to genetic disorders if errors occur.