Sponges (Phylum: Porifera)

Sponges have an asymmetric body with no true tissues, or organs. They have two layers of cells. Flattened cells cover the exterior. Collar cells line the interior chambers. Collar cells move large volumes of water through body pores by their beating flagella. They also trap suspended food particles in their microvilli collars.

This animation (Audio - Important) describes sponges.

Between the two layers of cells there is a semifluid matrix with needlelike structures for support.

Sponges reproduce sexually and have a free-living larval stage. They also reproduce asexually by fragmentation or gemmules.

Sponges (Phylum: Porifera)

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