BIOL 304

Question 1

What does deuterostome mean?

Answer 1

Animals where the anus forms first during embryonic development.

Question 2

What kind of environment are adult echinoderms found in?

Answer 2

Marine and benthic (seafloor).

Question 3

What is the lifestyle of echinoderm larvae?

Answer 3

Pelagic (free-swimming).

Question 4

Name the five major classes of echinoderms.

Answer 4

Crinoidea, Echinoidea, Ophiuroidea, Asteroidea, Holothuroidea.

Question 5

What is pentaradial symmetry?

Answer 5

Body parts arranged in fives around a central axis (seen in adult echinoderms).

Question 6

What kind of symmetry do echinoderm larvae have?

Answer 6

Bilateral symmetry.

Question 7

What is an endoskeleton made of in echinoderms?

Answer 7

Calcium carbonate ossicles and plates.

Question 8

What is mutable collagen tissue?

Answer 8

Connective tissue that can switch between stiff and flexible states.

Question 9

What does the water vascular system do?

Answer 9

Helps with locomotion, gas exchange, feeding, sensory reception, and attachment.

Question 10

What are tube feet?

Answer 10

Structures that use adhesive secretions for movement and attachment (not suction).

Question 11

What is an ambulacrum?

Answer 11

Main active region along which tube feet are located.

Think grooves

Question 12

What is an interambulacrum?

Answer 12

Areas between the ambulacra.

Question 13

What are pedicellariae?

Answer 13

Tiny pincer organs found on sea stars and sea urchins.

Question 14

What is autotomy?

Answer 14

Self-amputation of body parts for defense or escape.

Question 15

What are the two stomachs of a sea star called?

Answer 15

Cardiac stomach (external digestion) and pyloric stomach (internal digestion).

Question 16

What is evisceration in sea cucumbers?

Answer 16

Expelling internal organs to deter predators.

Question 17

What are Cuvierian tubules?

Answer 17

Sticky toxic threads used in sea cucumber defense.

Question 18

What is a respiratory tree?

Answer 18

Gas exchange structure connected to the anus in sea cucumbers.

Question 19

What is Aristotle’s lantern?

Answer 19

A five-tooth feeding structure in sea urchins.

Question 20

How do brittle stars differ in gut structure?

Answer 20

They have an incomplete gut (no intestines or anus).

Question 21

What is the feeding method of crinoids?

Answer 21

Suspension feeding using cilia to move particles into ambulacral grooves.

Question 22

What are bursae in brittle stars?

Answer 22

Sacs for respiration and excretion.

Question 23

What is a subepithelial nerve net?

Answer 23

A nerve network just under the skin for sensation and movement control.

Question 24

What are ocelli in sea stars?

Answer 24

Light-sensing organs.

Question 25

What are statocysts in sea urchins?

Answer 25

Balance-sensing structures.

Question 26

What is fissiparity?

Answer 26

Asexual reproduction by fragmentation and regeneration.

Question 27

What type of reproduction do most echinoderms use?

Answer 27

Gonochoristic (separate sexes) with broadcast spawning.

Question 28

What is the major body change during echinoderm metamorphosis?

Answer 28

Transformation from bilateral larvae to pentaradial adults.

Question 29

What is the function of the hydrocoel in larvae?

Answer 29

It develops into the water vascular system.

Question 30

What are the main respiratory structures across echinoderms?

Answer 30

Tube feet, papulae, bursae, and respiratory tree (depending on class).

Question 31

What is a keystone species?

Answer 31

A species whose impact on its community is disproportionately large compared to its abundance.

Question 32

How does Pisaster ochraceus influence its ecosystem?

Answer 32

Controls mussel populations, maintaining biodiversity.

Question 33

What common animals belong to Class Crinoidea?

Answer 33

Sea lilies and feather stars 🌸

Question 34

What common animals belong to Class Echinoidea?

Answer 34

Sea urchins and sand dollars 🧽

Question 35

What common animals belong to Class Ophiuroidea?

Answer 35

Brittle stars and basket stars 🌟

Question 36

What common animals belong to Class Asteroidea?

Answer 36

Sea stars (starfish) ⭐

Question 36

What common animals belong to Class Holothuroidea?

Answer 36

Sea cucumbers 🥒

Question 36

What is the role of the madreporite in a sea star?

Answer 36

It is a porous plate where seawater enters the water vascular system.

Question 36

What system in sea stars moves water to allow locomotion and feeding?

Answer 36

The water vascular system.

Question 37

How does water flow through a sea star's body? (Step-by-step = 6)

Answer 37

1. Water enters through the madreporite. 2. Flows into the stone canal. 3. Moves into the ring canal (around the mouth). 4. Flows into radial canals (one in each arm). 5. Enters lateral canals leading to tube feet. 6. Fills the ampullae which control the movement of the tube feet.