Mature diatoms undergo a process called vegetative cell division, which is a form of mitotic division distinct from meiotic division. This rapid division leads to a decrease in cell size rather than an increase, as the cells divide quickly without growing significantly in size beforehand. This phenomenon is similar to the early stages of animal embryonic development, where large fertilized eggs divide into smaller cells. The term "shrinking" refers to the fact that as diatoms divide, the resulting daughter cells are smaller than their parent cell, leading to a gradual reduction in size over successive divisions. The discussion also touches on the concept of asymmetric cell division, which is less common and occurs in certain unicellular organisms.
