Pore – bearers : Sponges Phylum Porifera Pore – bearers : Sponges

Characteristics of Sponges Most sponges are a mass of cells stuck together by a gel-like substance. Sponges are classified as animals because multicellular heterotrophic have no cell walls some specialized cells

Characteristics of Sponges, continued A sponge’s body is a sessile, filter-feeding structure. Water enters the sponge through ostia in the body wall and exits through the osculum.

Characteristics of Sponges, continued Lining the inside of a sponge is a layer of cells called choanocytes, or collar cells. Trap material on their flagella – like extensions Amoebocytes move around the body wall collecting nutrients and carry away wastes

Visual Concept: Feeding Habits of Sponges

Sponge Reproduction Sponges reproduce both asexually and sexually. Most sponges are hermaphrodites, they produce both eggs and sperm advantages?

Sponge Reproduction, continued Asexually Fragmentation Budding Freshwater produce gemmules, fluid – filled ball of ameobocytes Sexually External into water Larva is mobile

Groups of Sponges Sponges live in warm, shallow sea water and in deep, cold areas of the ocean. A few species even live in fresh water. There are three main types of modern sponges comprising the 5,000 species living today. All have skeletons which keep the sponge from collapsing in on itself.

Groups of Sponges, continued The skeleton of most sponges is comprised of tiny needles made of silica or calcium called spicules. A few sponges have a skeleton composed of a resilient, flexible protein fiber called spongin. Modern sponges are classified according to the composition of the skeleton in their body wall. Calcareous sponges have a hard skeleton while glass sponges have a latticelike skeleton.

Classification Phylum Porifera Class Calcarea (Calcium) Class Hexactinellida (Silica) Class Demospongia (Spongin)

Class Calcarea (Calcium)

Class Hexactinellida (Silica)

Class Demospongia (Spongin)

Summary Sponges are classified as animals because they are multicellular, are heterotrophic, have no cell walls, and contain some specialized cells. Sponges reproduce both asexually and sexually. Most sponges are hermaphrodites, which means they produce both egg and sperm. The modern sponges are classified according to the composition of the skeleton in their body wall.