Module 4: Marine Invertebrates Part 2

Class Anthozoa, corals and sea anemones represents the largest group of cnidarians. These organisms have a more complex structure than the hydrozoans or scyphozoans. Their gastrovascular cavity is lined with vertical partitions called Septa that provide greater surface area for digestion.  Most corals are made up of colonies of individuals with layers of ectodermal cells that secrete protective walls of calcium carbonate into which the polyps can hide when threatened. They have cup-like walls around each polyp.  These polyps remained attached to each one another after budding.  This forms the coral reef. Reef building corals grow faster than other corals because they have the help of symbiotic dinoflagellates called zooxanthellae.  Zooxanthellae produce carbon-containing compounds (like sugar) by photosynthesis, and they give some of those compounds to the corals. The corals then use the those compounds for energy, and they also use the carbon in those compounds to form the calcium carbonate they need to make the protective walls. Even through the corals get some food from the zooxanthelle, they also eat plankton that float in the water. Other notable anthozoa:

Colonial anthozoans that form branching or elongated skeletons: Sea Fans Sea Plumes Black Corals

Colonies that do not have hard skeletons:Soft Corals Sea Pens

No skeletons: Sea Anemoes

October 18, 2012 PowerPoint Honors Marine Biology Module 4 Corals

Our next wet lab field trip will be Saturday October 27, 2012 from 10:00am to 12:00 noon. Quick Point Park:  South end on Longboat Key.  Park on the left side of the road at the park. We will be using plankton nets and microscopes.


  1. Take Module 4 Test
  2. Read Module 5 pages:  97 – 107
  3. OYO Questions 5.1 – 5.5
  4. Study Guide Questions:  Define a-e and  questions 2-9
  5. Finish up labs
  6. Quiz:  Define and Draw the 3 Body Symmetry; Define mutualism, commensalism and parasitism. Where are tube worms found and what do they feed on.
  7. Class challenge:  Dress as your favorite Super Hero

The following videos are an excellent study of coral reefs in the Florida Keys.  The first two videos were shown in class.

Have a great week! -Mrs. S



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