echinodermata

Question 1

What are some distinguishing features of the phylum echinodermata?

Answer 1

deuterostomes, no distinct brain (radial nerves and circumoral ring), complete digestive system, no circulatory system (uses coelom), gas exchange occurs through dermal branchiae or other specialized systems, endoskeleton made of calcium carbonate ossicles, bilateral symmetry as larva but pentaradial symmetry in adults

Question 2

What are the differences between deuterostomes and protostomes?

Answer 2

deuterostomes develop the anus first from the blastopore, undergo indeterminate development, and embryonic cells divide by radial cleavage

Question 3

What is the function of the pedicellaria?

Answer 3

defense and clean epidermis

Question 4

What are some distinguishing characteristics of class asteroidea (sea stars)?

Answer 4

carnivorous predators, mouths on oral side, tube feet for locomotion, aboral madreporite as entrance to water vascular system, anus on aboral side, pedicellaria and spines

Question 5

What are the function of spines in echinoderms?

Answer 5

support and protection

Question 6

What is the function of the pyloric ceca?

Answer 6

digestive glands that secrete enzymes

Question 7

What is the function of the ambulacral groove?

Answer 7

lined with tube feet which are used for locomotion

Question 8

Where are the ambulacral ossicles located in a sea star?

Answer 8

above the radial canal and radial nerve

Question 9

What is the function of the water vascular system?

Answer 9

uses hydraulic pressure to power the tube feet by expanding/contracting the ampullae. for locomotion and capturing prey

Question 10

What are some distinguishing features of class ophiuroidea?

Answer 10

long skinny arms that are distinct from the central disk. deposit or suspension feeders. move by crawling rather than tube feet. madreporite located on oral surface rather than aboral

Question 11

What are the distinguishing features of the class echinoidea?

Answer 11

rigid shell called test that is formed by fusion of skeletal ossicles, pedicellariae can excrete poisons, aristotle’s lantern

Question 12

What are regular echinoids?

Answer 12

sea urchins, medium to long spines, move with tube feet and spines, hemispherical shape, radial symmetry

Question 13

What are irregular echinoids?

Answer 13

sand dollars, secondary bilateral symmetry, short spines, locomotion with spines

Question 14

How do echinoids accomplish gas exchange?

Answer 14

skin gills

Question 15

What is the ring surrounding the mouth and teeth on echinoids called?

Answer 15

peristome

Question 16

What are the feeding habits of echinoids like?

Answer 16

herbivores, use aristotle’s lantern to scrape off algae

Question 17

What are the distinguishing characteristics of holothuroidea?

Answer 17

oral/aboral axis elongated, ring of tentacles surrounding mouth for deposit feeding, lack arms, spines, pedicellariae, and ossicles are reduced to microscopic level

Question 18

How do holothuroids accomplish gas exchange?

Answer 18

sea cucumbers use respiratory trees to accomplish gas exchange with the cloaca pumping water in and out

Question 19

What takes up the majority of the internal structure of holothuroids?

Answer 19

the gonads

Question 20

Trace the digestive system of echinoids.

Answer 20

mouth, esophagus, stomach, intestine, anus

Question 21

What is the function of the stone canal?

Answer 21

connects the madreporite to the ring canal

Question 22

How is the madreporite different in holothuroids than other echinoderms?

Answer 22

the madreporite in sea cucumbers floats freely inside holothuroids and uses coelomic fluids to generate hydraulic pressure

Question 23

Where is the cloaca located in holothuroids?

Answer 23

next to the anus