Final answer:
Meiosis primarily differs from mitosis in halving the chromosome number to produce haploid cells and introducing genetic variation. These distinctions mainly take place during meiosis I, which involves pairing and crossing over of homologous chromosomes.
Step-by-step explanation:
Major Differences Between Meiosis and Mitosis
The process of meiosis differs from mitosis in two major ways:
- During meiosis, the number of chromosomes in the cells is halved, producing haploid gametes, compared to mitosis where the chromosome number remains the same, thus producing diploid cells.
- Meiosis introduces genetic variation through events such as crossover and independent assortment, which are absent in mitosis. This variation is critical to the process of sexual reproduction.
The fundamental differences between these two processes are most pronounced during meiosis I, where the mechanism of pairing of homologous chromosomes, chiasmata formation, crossover between nonsister chromatids, and the alignment of tetrads on the metaphase plate, lead to increased genetic diversity and reduction in chromosome number.
While both processes involve the division of a cell nucleus, the key outcomes of mitosis are two genetically identical daughter cells, supporting growth and tissue repair, whereas meiosis results in four genetically varied gametes for the purpose of reproduction.