Hundreds of pores are so small that they are invisible to the naked eye that they are scattered on the surface of the sponge's body. In fact, the sponge phylum, the name of the group to which the sponge belongs, means "has pores." It is the key to the survival of the sponge, as moving water carries food and removes waste products.
How does a sponge survive without a digestive system?
The sponge has no nervous system, digestive system, or circulatory system. Instead, most people rely on maintaining a constant stream of water through their bodies to get food and oxygen and get rid of waste products.
Why are there no organs in the sponge?
Unlike protozoa, sponges are multicellular. However, unlike higher metazoans, the cells that make up the sponge are not organized into tissues. Therefore, the sponge lacks true tissue and organs. Moreover, they have no body symmetry.
What helps the sponge survive?
Sponges live at all depths under different conditions, both in marine and freshwater environments. They are "insignificant" animals (not moving around), pumping large amounts of water into their bodies and filtering small organisms and organic particles for food.
How does the sponge repair itself?
Sponges are the only animals that can reconstruct themselves when broken down to the cellular level. A sponge is passed through a sieve to break down the cells. The cells recognize each other and reshape into small new sponges.