Coral Reefs Chapter 16

Reef-building corals are cnidarians that are characterized by: 

• Having both a polyp and medusa stage
• Lacking nematocysts
• Having mostly a medusa stage
• Having only a polyp stage

Reef-building corals are classified as

• Metamorphic
• Ametamorphic
• Hermatypic
• Ahermatypic

Planula is the name given to

• Corals that do not build reefs
• Coral larvae
• The coral skeleton
• The coral polyp

Zooxanthellae are essential to reef-building corals because they:

• Help in the deposition of the calcium-carbonate skeleton
• Provide the coral with protection from predators
• Provide the coral with carbon dioxide
• Provide the coral with protection from predators

Which of the following is not a source of food and other essential nutrients for corals

• Nutrients released by zooxanthellae
• Calcium carbonate from shells
• Dissolved organic matter (DOM) from the water
• Capture of food using mesenterial filaments

Which of the following is not used directly by corals for nutrition

• Mesenterial filaments
• Photosynthesis
• Mucus
• Tentacles

Why are reef-building corals limited to shallow waters? 

• Salinity varies less in shallow water
• Calcium carbonate is only available in shallow water
• Zooxanthellae need light for photosynthesis
• Nutrients concentrate in shallow water

The expulsion of zooxanthellae due to unfavorable conditions is called

• Exudation
• Bleaching
• Decalcification
• Denudation

Eutrophication is very detrimental to the development of coral because it increases

• The amount of nutrients in the water, hence providing the conditions for the overgrowth of algae
• The temperature of the water, which kills the corals
• The temperature of the water, which kills the zooxanthellae
• The salinity of the water, which kills the corals

Which of the following organisms is least likely to be responsible for bioerosion

• Sea urchins
• Fish
• Clams
• Algae