What occurs when gametes join at fertilization?

When gametes join at fertilization, the process leads to the restoration of the normal chromosome number in the resulting zygote. In humans, for example, each gamete (sperm or egg) contains half the number of chromosomes needed for a complete set, which is 23 chromosomes. The fusion of these two gametes during fertilization combines their genetic material, resulting in a zygote with the full complement of 46 chromosomes.

This is pivotal for maintaining species-specific chromosome numbers across generations. Each time fertilization occurs, genetic diversity is ensured through the combination of genetic material from two different parents. As a result, this restoration of the normal chromosome number is fundamental to reproduction and the continuity of genetic information in living organisms. The zygote will then undergo further development and divisional processes to grow into a new organism.