The Sponges

General Characteristics  Porifera means “full of holes”  Sponges are the simplest of animals  Live in both freshwater and saltwater.  Two cell layers thick, with gel-like substance between them.  Do not have tissues, organs, or organ systems.  Do have specialized cells and cell structures.

Specialized Cell Structures  Spicules- needle-like skeleton made of spongin  Amoebocytes- cells that carry food to other cells  Collar cells- trap food using flagella

Obtaining Food and Such  Water flow carries Food and Oxygen into the pores and out the osculum.  Waste produced are released into the water.  Gas exchange occurs through diffusion.  No nervous or circulatory system.

Reproduction  Can occur in three ways:  Asexual 1. Regeneration: new organism grows from a piece of the old. 2. Budding: new organism grows on old, falls off, and develops into an adult.

Reproduction  Sexual: Either sperm is released into the water and carried to a sponge egg where fertilization occurs Or, sperm and eggs are released into the water and fertilization occurs outside the sponge’s body  Most sponges are hermaphroditic, meaning they can produce both sperm and eggs. Just not at the same time.

Importance of Sponges  Natural sponges are used for cleaning or bathing.  Sponges are sources of powerful antibiotics.  Sponges are homes for other organisms.  Food source for some organisms.

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