Final answer:
The possible combinations of maternal and paternal chromosomes in an organism's gametes are calculated as 2 to the power of the haploid number n, which in humans is 2^23 or over 8 million combinations due to meiosis.
Step-by-step explanation:
In an organism with a haploid number (n), the possible combinations of maternal and paternal chromosomes in its gametes can be calculated using the formula 2n. For humans, the haploid number is 23, which means there are 223 or over 8 million possible combinations. This incredible variety results from the process of meiosis, where independent assortment and random fertilization significantly contribute to genetic diversity.
During metaphase I of meiosis, chromosomes can arrange themselves in many configurations as they line up on the metaphase plate. Every gamete thus has the potential for tremendous genetic variation. This variation is amplified when considering that a sperm cell with its vast combination possibilities fertilizes an egg cell with an equally large set of combinations, resulting in a zygote with a virtually unimaginable number of genetic makeup configurations.