Deuterostomes

Question 1

What are the three clades of Deuterostomes?

Answer 1

Hemichordata, Echinodermata, Chordata

Question 2

What are Hemichordata?

Answer 2

acorn worms

Question 3

What are Echinodermata?

Answer 3

sea urchins, sea stars

Question 4

What are Chordata?

Answer 4

vertebrates and two lineages of invertebrate animals

Question 5

What are distinguishing features of Hemichordata (acorn worms)?

Answer 5

threefold division of the body 1) proboscis, 2) collar 3)trunk with pharyngeal gill slits and a dorsal nerve cord

Question 6

What does the muscular proboscis do in Hemichordates? for what purpose?

Answer 6

burrows into sand or mud; detritus feeders, extracting organic material from sand or mad

Question 7

What features of hemichordates are shared with chordates?

Answer 7

branchial openings (gill slits)
stomochord in hemichordates resembles notochord
posses a dorsal nerve cord

Question 8

What is the relationship between hemichordates and echinoderms?

Answer 8

they are sister taxa

Question 9

What is a significant feature of Echinoderms? (they are deuterostomes…)

Answer 9

they secondarily evolved radial symmetry
larvae are bilaterally symmetrical

Question 10

What are general characteristics of Echinoderms?

Answer 10

pentamerous (sets of 5) radial symmetry
poorly ganglionated; possess diffuse sensory structures
body wall contains endoskeleton of calcareous plates
water vascular system

Question 11

What is tha water vascular system of echinoderms?

Answer 11

network of canals connected to podia (tube feet) extensions located on the oral surface.

Question 12

What is the water vascular system important for in echinoderms?

Answer 12

locomotion, feeding, and gas exchange

Question 13

What is reproduction like in echinoderms?

Answer 13

sexes are separate and fertilization is external

Question 14

Why does molecular sequence data suggest that hemichordates are closer related to echinoderms? (over chordates)

Answer 14

larva look similar

Question 15

What the 5 extant clades of Echinoderms?

Answer 15

Crinoidea
Asteroidea
Ophiuroidea
Echinoidea
Holothuroidea

Question 16

What are Crinoidea features?

Answer 16

ancestral lineage
oral surface directed upwards; aboral surface is attached to the substrate by means of a bendable stalk
suspension feeders

Question 17

What are Blastoids?

Answer 17

an extinct taxon of marine echinoderms
were stalked suspension feeders

Question 18

What are Asteroidea?

Answer 18

sea stars

Question 19

What are features of asteroidea?

Answer 19

typically 5 arms; merge with a central disc
mouth located in the center of oral surface directed downward
aboral surface with a madreporite opening of the water vascular system

Question 20

What are the cleaning structures found on the aboral surface of sea stars?

Answer 20

pedicellariae (or jaws)
bonus: papulae are used for gaseous exchange

Question 21

What are features of Echinoidea?

Answer 21

body is enclosed in shell or test
lack extended arms; fused to the test
body is usually covered with moveable spines

Question 22

What are examples of Echinoidea?

Answer 22

sea urchins and sand dollars

Question 23

What is Aristotle’s Lantern?

Answer 23

complex chewing apparatus used by sand dollars and sea urchins to feed by scraping algae off hard surfaces

Question 24

What is an example of a holothuroidea?

Answer 24

Sea cucumbers

Question 25

What are features of holothuroidea?

Answer 25

lack arms
oral-aboral axis greatly extended
tentacles collect food
endoskeleton is reduced to dermal ossicles scattered over the surface of the animal, making the soft bodied