Why do mature diatoms undergo vegetative cell division?

[Stephen Tashi]

This page indicates that mature diatoms begin to shrink as they age due to "vegetative cell division". http://www.sciencebythesea.org/SciencebytheSea.org/TAS-2014_Log/Entries/2014/7/10_Can_Diatoms_Iron-Out_Their_Differences_2.html What kind of cell division is "vegetative cell division"?

 

[BillTre]

Although "vegetative division" can have different meanings in difference contexts, in your link it seems to mean just mitotic (normal cell division) as distinct from meiotic divisions, which reduce the number of chromosomes by half to make germ cells.
From the link, it seems the cells just get smaller because they are dividing rapidly instead of growing 2x in size before dividing again.
Animal embryos often do this after fertilization (in the blastula stage) to make many small cells from the large fertilized egg.

 

[Chris Riccard]

From what I understand cells of animals divide with (till?) Specialisation of stem cells which are triggered by hormone receptors based on proximity.

 

[Fervent Freyja]

Amitiosis. It is an asymmetric cell division that occurs rarely in some unicellular and acellular organisms.

Not sure what is meant by "shrinking", but one cell is going to be smaller, so?