Porifera Characteristics

Symmetry
Sponges are rarely symmetrical, so most of their body structure are often irregular. This is because sponges form either from the piling of deceased skeletons or by calcium. Often times, new sponges start budding of the original sponge, but stay intact. Due to natural reasons, some sponges do inhibit radial symmetry or bilateral symmetry.

Reproduction
Sponges reproduce asexually and sexually. Some sponges release sperm which is caught by nearby sponges and fertilization of the egg begins. After fertilization in the sponge, a larva is released into the water. The larvae floats around until it  sticks to a secured solid to begin its growth into an adult sponge. Over time, these sponges can create new coral reefs in the globe's oceans.

Organs
Sponges don't have a pure organs or true tissue. Instead, they contain cells that carry out the functions that usual organs do. Before being harvested, sponges have hard, shell-like protective outer layer covered with tiny pore-like holes which travel deep down into and all throughout the soft structure within. Particles float to these pores, and get trapped by the amoebic and epidermal cells. ​