Unchanged for hundreds of centuries, and with no close relatives on the evolutionary tree, the sponge remains a very simple and primitive form of animal. Sponges have a remarkable ability to withstand tremendous loss of body material, suddenly growing many times faster than normal to regain the original size. It is even possible that certain types of sponges to be passed through a fine sieve, their bodies broken down to the components cells, and reform themselves again over a period of hours or days. The average lifespan for individual specimens has been estimated to be 50 years or more.
The simplest form of sponge is shaped somewhat like a vase, with feeding cells on the inner wall. Water is drawn through minute pores in the outer wall and expelled through the large principal aperture. The present is maintained by the feeding cells, each with a very small whip that’s waved continually back and forth. Due to the large volume of water contained inside the chamber in proportion to the interior wall surface of feeding cells, higher forms of sponges have accommodated by folding out the interior walls to improve the feeding area.
On low tide areas of the beach may be found many of the flat in crusting sponges. These appear in a huge array of colors and have no definite shape of their own, instead taking on the kind of the rock beneath.
Some types of sponge are capable of releasing a noxious substance to stop the encroachment of acquaintances, and many of these poisons are used in research laboratories for the preparation of human medications.