Identify the common characteristics of phylum Porifera

Figure 1. Sponges are members of the Phylum Porifera, which contains the simplest invertebrates. (credit: Andrew Turner)

The invertebrates, or invertebrata, are animals that do not contain bony structures, such as the cranium and vertebrae. The simplest of all the invertebrates are the Parazoans, which include only the phylum Porifera: the sponges (Figure 1).

Parazoans (“beside animals”) do not display tissue-level organization, although they do have specialized cells that perform specific functions. Sponge larvae are able to swim; however, adults are non-motile and spend their life attached to a substratum. Since water is vital to sponges for excretion, feeding, and gas exchange, their body structure facilitates the movement of water through the sponge. Structures such as canals, chambers, and cavities enable water to move through the sponge to nearly all body cells.

What You’ll Learn to Do

• Describe the organizational features of the simplest multicellular organisms
• Explain the various body forms and bodily functions of sponges

Learning Activities

The learning activities for this section include the following:

• Morphology of Sponges
• Physiological Processes in Sponges
• Self Check: Phylum Porifera