Coral reefs

Question 1

What are coral reefs ?

Answer 1

Calcium carbonate secretions from hard corals; creating a wave resistant feature.

Question 2

What are is the Phylum, Class and Order of corals ?

Answer 2

Cnidaria, Anthozoa and Scleractinia

Question 3

What are the 2 main body types of Cnidaria corals.

Answer 3

Polyp or Medusa

Question 4

What are the names and differences in environment between reef building and non reef building corals ?

Answer 4

Reef building corals are called hermatypic corals and non reef building corals are ahermatypic. Hermatypic occur in shallow, clear waters and ahermatypic occur much deeper and waters may be clear or unclear.

Question 5

What is the name of the algae with which corals form a symbiotic relationship with ?

Answer 5

Zooxanthellae

Question 6

Name the two types of reef building coral structures and describe their form.

Answer 6

Massive corals are mound shaped and grow slowly. Branching corals grow like trees and elkhorns; they grow rapidly.

Question 7

Name and describe the two types of asexual reproduction in corals.

Answer 7

Budding is where new polyps “bud” off from the parent coral polyps. Fragmentation is where a whole colony of polyps break off during a storm or boat grounding e.t.c

Question 8

Name the three types of sexual types of corals there are.

Answer 8

Hermaphrodites, gonochoristic (single sex) and some change sex throughout life time.

Question 9

Whats the difference between brooding and broadcasting sexual production in corals ?

Answer 9

Broadcasters release their gametes usually in mass spawning evemts every year. Fertilization occurs externally. Brooders fertilize in the gastrovascular cavities with motile sperm. The larvae are then released to settle nearby.

Question 10

Name the three possible triggres for mass spawning

Answer 10

Day legnth, lunar cycle and water temperature.

Question 11

What is the name of coral larvae and how do they form new clonal colonies ?

Answer 11

Coral larvae are called planulae. They will settle on suitable substratum after a matter of days/ weeks. They then undergo metamorphisis into a polyp. Through budding they form a clonal colony.

Question 12

Name the two aggresive features some coral species posess.

Answer 12

1. Mouth polyps that release mesenterial filaments which are digestive filaments
2. Sweeper tentacles which contain nematocysts (stinging cells)