Final answer:
Chromosomes during fertilization come from both the mother's egg and the father's sperm, with each contributing 23 chromosomes. Independent assortment during meiosis increases genetic diversity by randomizing the distribution of maternal and paternal chromosomes. Each parent's gametes carry half their chromosomal complement, ensuring offspring have the same total chromosome number.
Step-by-step explanation:
During fertilization, each chromosome originates from one of two sources: the mother or the father. In humans, the egg donated by the mother carries one set of 23 chromosomes. Conversely, the father contributes the other set of 23 chromosomes through the sperm that fertilizes the egg. This fusion of gametes during sexual reproduction ensures that every cell in the offspring contains a full complement of chromosomes, half from each parent. The phenomenon of independent assortment during meiosis I is crucial as it leads to the random orientation of maternal and paternal chromosomes, which significantly contributes to genetic diversity. Furthermore, each parent synthesizes gametes that hold only half of their chromosomal complement. This ensures that the offspring retains the same chromosome number as their parents, and it is this process, combined with the vast number of potential gamete combinations, that underpins the vast genetic variation observed in sexually reproducing populations.