1. Pore – bearers : Sponges
Phylum Porifera
Pore – bearers : Sponges

2. 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

3. 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.

4. 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

5. Visual Concept: Feeding Habits of Sponges

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

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

8. 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.

9. 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.

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

11. Class Calcarea (Calcium)

12. Class Hexactinellida (Silica)

13. Class Demospongia (Spongin)

14. 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.