This is used by each daughter cell as the larger frustule ( or epitheca ) into which a second, small frustule ( or hypotheca ) is constructed.
12.
Diatoms build a frustule from silica extracted from the surrounding water; radiolarians, foraminiferans, testate amoebae and silicoflagellates also produce a skeleton from minerals, called lorica.
13.
Diatoms are traditionally divided into two main groups that are primarily distinguished by frustule structures : the "'centrics "'and the "'pennates " '.
14.
This form of division results in a size reduction of the daughter cell that received the smaller frustule from the parent and therefore the average cell size of a diatom population decreases, until the cells are about one-third their maximum size.
