Final answer:
Meiosis is a cell division process that produces four haploid cells from germ cells in sexual organisms, introducing genetic variation through crossing-over and random chromosome alignment.
Step-by-step explanation:
Understanding Meiosis
Meiosis is a type of cell division specific to germ cells—cells that give rise to gametes—for sexual reproduction. Germ cells are located in the ovaries of females and the testes of males. Unlike mitosis, which results in two genetically identical diploid cells, meiosis produces four genetically unique haploid cells. These haploid cells, or gametes, contain half the genetic material of the original cell and can develop into sperm in males or eggs in females.
In the process of meiosis, there are two consecutive division stages: Meiosis I and Meiosis II. Meiosis I separates homologous chromosomes, and Meiosis II, resembling mitotic division, separates sister chromatids. This two-step division results from an initial round of DNA replication followed by two rounds of nuclear division, producing four, not two, daughter cells, each with half the number of chromosomes as the parent cell. Genetic variation is introduced through events like crossing over during prophase I and during the random alignment of chromosomes during metaphase I.
Sexual reproduction involves the fusion of two haploid gametes, resulting in a diploid zygote. This process allows for a mix of genetic material, leading to the potential for significant genetic diversity in the offspring.