Most are sponges are asymmetrical, though some of them exhibit radial symmetry (Dawkins 2004). As an adult they may have multiple cell layers, but initially they all arise from the two layers that were present in the early embryo (Dawkins 2004). They are known be diploblast, which means having two layers of cells (Dawkins 2004). Like plants they move at the cellular level (Dawkins 2004). They stay put in one place stuck to the bottom of the water- either salt or fresh. Like plants they do not move, i.e., they are sessile. This misconception is due to some of the characteristics of the Porifera (Dawkins 2004). People often think of sponges as plants, rather than being animals. Some molecular taxonomists think that there are two lineages of sponges, one more closely related to other more complex Metazoans than the other. Today the rest of the Metazoans are considered to belong to Eumetazoa. For a long time they were written off as ‘parazoa’.

Sponges are the first and most simple members of Metazoa in the ancestral lineage of animals (Dawkins 2004). Classes: Calcarea, Demospongiae, Hexactinellida.Some of these sponges are very colorful and beautiful (1). There are many different types of sponges all over the world. Sponges are very primitive creatures that evolved around 500 million years ago (1). The rest of the sponges dwell in salt-water. Out of them only 150 species live in fresh water. There are about 5000 to 10,000 of species of Porifera that are known today. The Poriferans are simple multi cellular animals.

They are stuck to the floor in the oceans, sea, and rivers. The sponges are living animals that live in the water. It is easy to forget that there is much more to sponges than the scrubbing and bath. The word sponge, for most of us relates to the scrubbing sponge or a bath sponge.

Does young sponge move