Bryozoans are most likely to be found in marine environment, typically growing on surfaces of things, such as rocks, kelps, shells, fossils, and even on pipes and ships. Developed in colonies, some individuals gather up the food for the colony (autozooids), others depend on them (heterozooids). Some individuals devote to strengthen the colony (kenozooids) and vibracula clean the colony. These species have what's called "blind-ended" gut, pouch-like intestines where mouth and anus is same opening. Bryozoans do not have any defined respiratory, circulatory, and nerve system due to their size. Bryozoans have hydrostatic skeletal system.
Bryozoa is one of the few classical phyla from which no members have been found in the Cambrian. They seem to have evolved in the Ordovician.