why are sponges considered primitive animals
Sponges are primitive, sessile, mostly marine, waterdwelling filter feeders that pump water through their matrix to filter out particulates of food matter. Sponges are among the simplest of animals, with partially differentiated tissues but without muscles, nerves, or internal organs.he structure of a sponge is simple: it is shaped like a tube, with one end stuck to a rock or other object and an open end, the osculum, open to the environment. The spongocoel, or interior of the sponge, is composed of walls perforated with microscopic pores that allow water to flow through the spongocoel.
People often think of sponges as plants, rather than being animals. This misconception is due to some of the characteristics of the Porifera (Dawkins 2004). Like plants they do not move, i.e., they are sessile. They stay put in one place stuck to the bottom of the water-either salt or fresh.he Life of a Sponge. Elephant ear sponge, Â© 2006 Richard Ling. The word sponge, for most of us relates to the scrubbing sponge or a bath sponge. It is easy to forget that there is much more to sponges than the scrubbing and bath.