The extinction of a species would negatively affect human society because we may rely on that species for resources, or other species that interact with the extinct species may begin to decline, and those species could be essential to human survival.
(See figure below, where meiosis I begins with a diploid (2n = 4) cell and ends with two haploid (n = 2) cells.) In humans (2n = 46), who have 23 pairs of chromosomes, the number of chromosomes is reduced by half at the end of meiosis I (n = 23).