Zoology 10th Edition by Stephen Miller,John Harley

Exercise 3

Meiotic cell division is the process that results in the formation of haploid (1 N ) gametes. Gamete formation involves two meiotic and cytoplasmic divisions during which homologous pairs of chromosomes undergo synapsis, including crossingover, followed by the separation of members of each pair into gametes that have one-half the number of chromosomes of the parental cells. Fertilization restores the diploid (2 N ) chromosome number in the zygote.
Why are the events of the first meiotic division so very important in the outcome of the entire meiotic cell division process?