Final answer:
The chromosome number reduction takes place during anaphase I of meiosis I, where homologous chromosomes are separated, resulting in haploid daughter cells.
Step-by-step explanation:
During meiosis, the chromosome number is reduced by half in anaphase I. This phase is part of meiosis I, which is often referred to as the reduction division because it reduces the ploidy level from diploid to haploid. Homologous chromosomes, which are pairs of chromosomes that contain the same genes but possibly different alleles, are separated and pulled to opposite poles of the cell during anaphase I. As a result, the two resulting daughter cells have half the number of chromosomes compared to the original cell. In contrast, meiosis II resembles mitosis, where sister chromatids are separated during anaphase II, producing four genetically unique haploid cells by the end of the process.