Phylum Echinodermata

Question 1

Symmetry

Answer 1

Penta-radial adults with bilateral larva

Question 2

What kind of larva?

Answer 2

Bilaterally symmetric

• Pluteus
• Bipinnaria
• Auricularia

Question 3

How do echinoderms respire

Answer 3

Dermal Branchiae or tube feet

• Sea cucumbers have respiratory tree
• Brittle stars have bursae

Question 4

7 Echinoderm characteristics

Answer 4

• Deuterstome
• Eucoelomate
• Internal skeleton of calcareous ossicles
• No cephalization (secondarily lost)
• No excretory organs
• Dioecious
• External fertilization

Question 5

Which class may brood larva?

Answer 5

Ophiuroidea may sometimes brood larva in bursae

Question 6

Protostome vs. Deuterstome development

Answer 6

• Fate of Blastopore (determinant or indeterminant)
• Spiral vs. Radial cleavage
• Schizocoelous vs. enterocoelus (Mesoderm split vs. outpockets of archenteron form coelom)

Question 7

What are the 5 classes in Phylum Echinodermata?

Answer 7

• Asteroidea
• Crinoidea
• Holothuroidea
• Echinoidea
• Ophiuroidea

Question 8

How many arms does Asteroidea have?

Answer 8

5 or more that merge gradually with a central disc

Question 9

What is the skeleton of Asteroidea

Answer 9

endoskeleton of ossicles bound by connective tissue

Question 10

What are ossicles?

Answer 10

Internal calcareous skeleton (plates in asteroidea)

Question 11

Does asteroidea have spines?

Answer 11

Yes, tubercules on ossicles with spines

Question 12

Where are the tube feet located in Asteroidea?

Answer 12

along the abulacral grooves, topped with suckers

Question 13

What are pedicellariae?

Answer 13

Pincher-like appendages on the skin surface that are used for defense and keeping the surface skin clear of debris
- Found in Asteroidea and Echinoidea

Question 14

What are papulla?

Answer 14

Used for gas exchange, found on skin surface

Question 15

Where is the madreporite on Asteroidea?

Answer 15

The aboral surface

Question 16

How do sea stars feed?

Answer 16

• Feed on molluscs, crustaceans, polychaetes, echinoderms, and other inverts
• Digestion is external by everting stomach, rarely internal
• Larger waste material discharged by the mouth

Question 17

What is the sea star habitat?

Answer 17

Shallow waters and lower intertidal on rock, sand or mud substrates

Question 18

What are the larval types of asteroidea?

Answer 18

Bipinnaria and then brachiolaria planktonic larva

Question 19

How many arms do brittle stars have?

Answer 19

5 arms set off sharply from central disc and made of a column of ossicles connected by muscles and covered by plates

Question 20

Where is the madreporite in Ophiuroidea?

Answer 20

The oral surface

Question 21

What are bursae

Answer 21

Pockets between the arms of ophiuroidea that are used for respiration, brooding larvae and possibly filter feeding

Question 22

Characteristics of Ophiuroidea

Answer 22

• 5 arms set off from central disc
• No pedicellariae or papula
• Ambulacral groove closed and covered w/ ossicles
• No suckers on tube feet
• Madreporite on oral surface
• No anus or intestine
• Spines located on the sides of the arms
• five pairs of bursae between each arm
• Great powers of regeneration

Question 23

Ophiuroidea habitat

Answer 23

Benthic marine at all depths and substrates

Question 24

Ophiuroidea

Answer 24

Brittle stars

Question 25

Ophiuroidea feeding

Answer 25

suspension feeders using mucus on tube feet, or browsers/snaggers

Question 26

Ophiuroidea reproduction

Answer 26

``` dioecious external fertilization ophiopluteus larva gonads empty into the bursae some species brood young in bursae and release juvenilles ```

Question 27

What has happened to the ossicles in Echinoidea?

Answer 27

Fused to form the internal skeleton known as a test

Question 28

Where are the anus and madreporite on the echinoidea?

Answer 28

The aboral surface

Question 29

What is Aristotle's lantern?

Answer 29

The specialized feeding apparatus in Echinoidea that is most well developed in the urchins and has 5 teeth

Question 30

What is the feeding mode of the Echinoidea?

Answer 30

Algal grazers using Aristotle's lantern or filter /detritus feeders with mucous on tube feet

Question 31

Echinoidea reproduction

Answer 31

dioecious, external fertilization, echinopluteus planktonic larva

Question 32

Echinoidea habitat

Answer 32

Shallow to deep sea, urchins like hard substrate, dollars and heart urchins like sandy substrate

Question 33

Why is there sand in sand dollars?

Answer 33

The sand in sand dollars is used for weight balance.

Question 34

What is the issue with japanese eel grass?

Answer 34

It is stabilizing sand and reducing sand dollar habitat

Question 35

Characteristics of class Holothuroidea

Answer 35

- Elongated aboral-oral axis - Reduced ossicles scattered within the epidermis - Ambulacral region is well developed on one side - 10 to 30 tentacles used mostly for filtering - Respiratory tree for gas exchange - Eviscerates internal organs to distract predators

Question 36

Holothuroidea feeding mechanisms

Answer 36

suspension or deposit feeding with tentacles modified for feeding mode that can be retractable

Question 37

Holothuroidea Reproduction

Answer 37

dioecious, external fertilization, free swimming Auricularia larvae or brooded on female

Question 38

Holothuroidea Habitat

Answer 38

Hard or soft substrate intertidal to super deep

Question 39

Characteristics of Class Crinoidea

Answer 39

- Body disc with leathery skin and calcareous plates - 5 flexible arms branched at base bearing pinnules - No madreporite, spines, or pedicellariae - Upper surface is oral bearing mouth and anus - Tentaculate tube feet in abulacral groove

Question 40

Crinoidea Feeding

Answer 40

Use tube feet and mucous net to catch small organisms with ciliated ambulacral groove that transports food to the mouth

Question 41

Crinoidea Reproduction

Answer 41

Dioecious with free swimming Dollolaria larvae

Question 42

Crinoidea Habitat

Answer 42

Shallow tropical pacific and caribbean but also many deep water species

Question 43

What are the issues with sea urchin fisheries?

Answer 43

- Urchin barrens were thought to reduce diversity and so urchins were heavily fished. However, it wasn't the barrens that were often fished and because urchins in barrens don't have well developed gonads, the populations greatly decreased.