Introduction to Bryozoans



Colony of encrusting bryozoan (Figularia figularis) from the Holocene of California.

Bryozoans are colonial aquatic invertebrate animals like corals that form colonies composed of thousands of genetically identical individuals that are added to the colony asexually like building blocks.  Economically, bryozoans are important fouling organisms of marine vessels and power plant water cooling systems as well as sources of natural anticancer compounds.  Academically, bryozoans are important tools for testing evolutionary, ecological, and sedimentary hypotheses.  Their utility in these studies is a function of their a) long fossil record (500 million years), b) diverse fossil record (>16,000 species), c)abundant fossil record (some rocks > 50% bryozoans by volume), and d) ability to reproduce asexually.  Asexual reproduction is important for evolutionary studies as it permits a) discrimination of genetic and environmental components of morphologic variation, b) colonial organization which provides a minimum constraint on intraspecific variation, and c) large data sets for rigorous statistical analysis.