Cnidarians

Question 1

Why should be study fossil corals?

Answer 1

a) Corals are very simple organisms that are voracious predatorsb) corals are excellent indicators of warm, shallow, marine paleoenvironmentsc) some coral taxa were major reef-builders d) coral reefs are (and were) among the diverse ecosystems on Earthe) some coral taxa are important biostratigraphic index fossils, especially rugose & tabulate corals in the Paleozoic

Question 2

Phylum Cnidaria Three classes:

Answer 2

Class ScyphozoaClass HydrozoaClass Anthozoa

Question 3

Class Anthozoa Subclasses:

Answer 3

Subclass CeriantipatheriaSubclass OctocoralliaSubclass Zoantharia

Question 4

Subclass Zoantharia Three Orders:

Answer 4

Order TabulataOrder RugosaOrder Scleractinia

Question 5

Class Scyphozoa:

Answer 5

true jellyfish; very poor fossil record

Question 6

Class Hydrozoa:

Answer 6

“fire corals” and their kin; sparse fossil record

Question 7

Class Anthozoa:

Answer 7

true corals and sea anemones; rich fossil record

Question 8

Subclass Zoantharia:

Answer 8

6 orders of hard corals + 3 orders of soft sea anemones

Question 9

Order Tabulata:

Answer 9

(tabulate corals), Early Ordovician to Permian

Question 10

Order Tabulata Geologic Range:

Answer 10

Early Ordovician to Permian

Question 11

Order Rugosa:

Answer 11

(horn corals), Middle Ordovician to Permian

Question 12

Order Rugosa Geologic Range:

Answer 12

Middle Ordovician to Permian

Question 13

Order Scleractinia:

Answer 13

(modern corals), Middle Triassic to Present

Question 14

Order Scleractinia Geologic Range:

Answer 14

Middle Triassic to Present

Question 15

Medusa:

Answer 15

Pelagic, sac-like body form or growth stage (Cnidarians)

Question 16

Polyp:

Answer 16

Benthic, barrel-like body form or growth stage (Cnidarians)

Question 17

Radial symmetry:

Answer 17

Multiple vertical symmetry planes radiating outward from the center (Cnidarians)

Question 18

Basal Disc:

Answer 18

Flattened top portion of the polyp, on which the mouth occurs (Cnidarians).

Question 19

Oral Disc:

Answer 19

Flattened top portion of the polyp, on which the mouth occurs. (Cnidarians)

Question 20

Mouth:

Answer 20

The single opening to the central cavity (enteron) (Cnidarians)

Question 21

Pharynx:

Answer 21

Throat-like tube leading from mouth into the central cavity (enteron). (Cnidarians)

Question 22

Tentacles:

Answer 22

Arm-like, cnidoblast-bearing structures surrounding the mouth. (Cnidarians)

Question 23

Enteron:

Answer 23

Central body cavity, which contains mesentery and digestive tissues. (cndarians)

Question 24

Mesenteries:

Answer 24

Radiating vertical sheets of tissue (Cnidarians)

Question 25

Cnidoblasts:

Answer 25

“stinging cells”, which contain the poisonous nematocysts (Cnidarians)

Question 26

Nematocysts:

Answer 26

Toxin-bearing sacs within the cnidoblasts (Cnidarians)

Question 27

Corallum:

Answer 27

Skeleton of the entire coral colony

Question 28

Corallite:

Answer 28

Skeleton of a single coral polyp.

Question 29

Theca:

Answer 29

Outer wall of corallite

Question 30

Calice:

Answer 30

Bowl-shaped top surface of corallite.

Question 31

Fossula:

Answer 31

Deep, slot-like indentation in calice.

Question 32

Columella:

Answer 32

Pillar (axis) in center of corallite.

Question 33

Septa:

Answer 33

Radiating, vertical, blade-like partitions inside corallite.

Question 34

Tabulae:

Answer 34

Stacked, horizontal, platform-like partitions inside corallite.

Question 35

Dissepiments:

Answer 35

Multiple domed plates connecting the septa inside corallite.

Question 36

Reef:

Answer 36

Biologically produced prominence on the sea floor

Question 37

Tabulate Corals:

Answer 37

(order tabulata), Early Ordovician to Permian (Syringopora & Favosites are colonial)

Question 38

Tabulate Corals Geologic Range:

Answer 38

Early Ordovician to Permian

Question 39

Horn Corals:

Answer 39

Order Rugosa, MIDDLE ORDOVICIAN TO PERMIAN, Heliophyllum & Cystiphyllum are solitary; Pachyphyllum & Hexagonaria are colonial

Question 40

Horn Corals Geologic Range:

Answer 40

Middle Ordovician to Permian

Question 41

Modern Corals:

Answer 41

Order Scleractinia, Middle Triassic to Present:(Montastraea & Septastrea are colonial)

Question 42

Modern Corals Geologic Range:

Answer 42

Middle Triassic to Present

Question 43

Coral ecology and paleoecology:

Answer 43

Corals are sessile, benthic carnivores that capture, poison, kill and devour tiny worms, crustaceans, etc. They typically are fully marine animals (no fresh water forms).

Question 44

Hermatypic:

Answer 44

(=reef-building) corals live in warm, shallow, clear, agitated, normal marine water. They house symbiotic algae (zooxanthellae) in their tissues, so they requrei sunlight.

Question 45

Ahermatypic:

Answer 45

(=non-reef-bulding) corals may live in cold, deep, marine water. They do not have zooxanthellae, so they do not require sunlight in their habitat.

Question 46

Geologic importance of Tabulate corals:

Answer 46

important reef-builders in Middle Ord. to Dev.

Question 47

Geologic importance of Rugose corals:

Answer 47

important facies and age indicators through their range.

Question 48

Geologic importance of Scleractinian corals:

Answer 48

Important reef-builders through their entire range.

Question 49

Reef formation: DRAW DIAGRAM A-D

Answer 49

Successive stages in the development of modern (scleractinian) coral reefs on subsiding volcanic islands (seamounts), as proposed by Charles Darwin from his observations made while sailing through the South Pacific on the voyage of the H.M.S. Beagle in the 1830’s. A,B, Volcanic island skirted by a fringing reef. C, Volcanic island with a lagoon and barrier reef encircling it. D, Coral atoll with a central lagoon and no vestige of an emergent island above sea level.