A florescent dye is injected next to a sponge and the sponge quickly pumps the dye through its body. This demonstrates that sponges actively pump large quantities of water through their bodies in order to extract tiny organisms for food from the water.
Sponges: Filter Feeding Made Visible
Next Generation Science Standards for this Video
Sponges don’t have tissues and organs. The beating choanocyte cells (specialized cells with flagellae) and the porous structure of a sponge’s body are specialized to pump water throughout the sponge’s body. This brings food to all the cells.