Sponges represent the simplest of animals. Sponges are asymmetrical, primitive, and sedentary animals which lack a mouth, digestive canal or any other normal organ.

Sponges are filter feeders that remove plankton (food) from the water. Marine sponges are larger & more colorful than freshwater sponges

Range in size from 2 centimeters to 2 meters

ORGANIZATION

They consist of a few types of cells, forming tissues that are supported by a skeleton made of a fibrous material namely collagen or spongin (as in the familiar bath sponge), or of lime or silica spicules, or of a combination of spongin and spicules.

Water and small food particles enter the sponge through numerous tiny pores which dot the surface of the body and exits through one or a few larger openings or oscula. Osculum is single, large body opening at the top for water and wastes to leave

The "skeleton" of the sponge is composed of tiny needle-like splinters called SPICULES, a mesh of protein called SPONGIN, or a combination of both.

Spongin is a network of flexible, protein fibers making up the sponge's skeleton
Spicules are made of calcium carbonate or silica

Most sponges reproduce sexually and are hermaphroditic (having both sexes in one), but produce only one type of gamete per spawn. (i.e. some play the male role and the other plays the female role, even though they are both capable of playing either role). The next time the sponges reproduce, they may change sexual roles.

Sponges can reproduce asexually by external buds that break off and form new sponges or stay attached to form sponge colonies.

Gemmules are specialized, internal buds formed by sponges during cold or dry weather that can survive harsh conditions

Sponge can also asexually regenerate missing parts or a new sponge from a small piece of sponge.