The porifera phylum.
- Organisms inside the porifera phylum carry out circulation the same way. They go through the process of diffusion, in which oxygen diffuses into the porifera and carbon dioxide diffuses out. The oxygen enters the blood stream as it flows through the body. This process occurs in the capillaries. The one organism that breaks the mold is the sponge. The sponge depends on water constantly flowing through the sponge to clean it and obtain food. The closest thing a sponge has are canals the water flows into where food and nutrients are trapped for the sponge. The openings of these canals are called pores. Over many years the sponge has developed into odd shapes that are most efficient for the water to flow through.