Phylum Porifera, or the sponge, is entirely aquatic, with over 98 percent living in the ocean, and the rest living in freshwater lakes and streams, according to BioMedia Associates. The sponge serves an important purpose in filtering bacteria and other contaminants from water, and it forms a significant portion of coral reefs. Many sponges are brightly colored and come in a diverse array of shapes.
As the simplest animal, the invertebrate sponge has few tissues and no organs, and its name derives from the many pores on its body. Sponges usually do not move on their own. They attach themselves to a substrate as adults, where they typically remain. The body of a sponge consists of cells and tissues, and the tissues contain canals with flagella that push water through in one direction to capture food and contaminants, provide water and remove waste, according to Earth Life.
Sponges are found in every climate all over the Earth, and there are more than 10,000 sponge species. While most sponges are hermaphroditic, they are only one gender at a time: female, male or neuter. Earth Life explains that the males release sperm into the water, and the female sponges draw the sperm in to fertilize the ovum, which are then released as little sponges. Sponges can also reproduce asexually by releasing little parts of themselves called gemmules.