or "moss animals" are colonial invertebrates that resemble
corals. Bryozoan colonies may grow as encrustations on
objects, form branching structures, thin lacey forms,
growths. Bryozoans are related to brachiopods. Bryozoans
range from the Ordovician to recent times.
called zooids are around 1 millimeter in length. A U-shaped
digestive tract has a mouth on one end surrounded by
of tentacles of the lophophore. The anus lies just outside
the ring of tentacles at the opposite end of the U-shaped
digestive tract. Most individuals are hermaphrodites. Zooids
secrete a chitinous
their body called a zooecia. The colonial skeleton is
called a zoarium. Colonies form when a single bryozoan
from sexual reproduction attaches to a surface.
The single animal asexually reproduces through budding
to form the colony. Colonies prefer clear water in which
they can filter feed on tiny plankton.
bryozoans represent colonies of zooids. Although the zooids
are long gone the pinhole-sized holes (zooecia) within the
zoarium can be identified and studied. During the Paleozoic
bryozoans were an important part of many reef systems. During
the Ordovician and Mississippian they were the second or
third most common fossil group after brachiopods and crinoids.
Science Olympiad Fossil Event
The 2011 Science Olympiad Fossil List includes the following
genera: Archimedes and Rhombopora. The
list also mentions three growth forms: branching, massive,