The beautiful corals, nasty jellyfish and mysterious sea life…Solar powered and build entire island chains over millions of years. Do you feel modest yet?
- Unifying Characteristics
- Old name - Coelenterata
- Majority marine, but a few freshwater species.
- Metazoan, with tissues, triploblastic, acoelomate.
- Phylum exhibits polymorphism. The two main structural types are the polyp and the medusa.
- May be solitary or colonial.
- Typical larval form is planula.
- Exhibit some form of radial symmetry.
- Generally possess a ring of tentacles around the oral end.
- The single body cavity is the coelenteron.
- The body wall is three-layered.
- Possess nematocysts, special cell organelles used for offense and defense, located in cnidoblast cells of epidermis and gastrodermis
- Possess undifferentiated interstitial cells (mesoglea), which gave rise to sex cells and cnidoblasts, and are also involved in regenerative and reproductive processes
- Nervous system a network and not centralized (nerve net)
- Coelenterata Classification (3 Classes)
- Class Hydrozoa
- hydrozoan forms two polyp types:
feeding polyps = gastrozooid,
reproductive polyps = gonozooid (medusae inside)
- statocysts - equilibrium organs on medusa
Physalia = Portuguese Man -of- War, not a true jellyfish , but a colonial, pelagic hydrozoan; velum - distinguishing character of a medusa
- medusa dominant, true jellyfish
- no velum
Aurelia – True jellyfish
Life Cycle: planula larvae ®
C. Class Anthozoa
- solitary or colonial, but only polyps
Examples: Sea pansy; sea fan; true corals, sea anemones
courtesy of Dr. Robert Richmond of the UOG Marine Lab, click below to see
more of the Marines Lab's world class research in Tropical Marine Biology)
University of Guam Marine Laboratory