Phylum Echinoderms

Question 1

What does Echinodermata mean

Answer 1

spiny skin-endoskeleton of dermal ossicels with projecting spines

Question 2

what are humans more closely related to than any other invertebrate group

Answer 2

echinoderms

Question 3

what type of symmetry do adult echinoderms have

Answer 3

radial symmetry

Question 4

what type of symmetry to larval echinoderms have

Answer 4

bilateral symmetry

Question 5

what is secondary radial symmetery

Answer 5

radial symmetry is secondarily derived, it is an advanced feature, not primitive one

Question 6

How well developed is cephalization in echinoderms, and
how well developed is their nervous system?

Answer 6

cephalization is reduced or absent in this group
nervous system is decentralized – no brain
most feed on small organic particles or algae, or small
prey
some (sea stars and sea urchins) are efficient predators
most are active, mobile animals

Question 7

function of water vascular system in echinoderms

Answer 7

respiration, locomotion, and excretion

Question 8

explain water flow through echinoderms

Answer 8

stone canal>ring canal>radical canal>lateral canal>ampulla>tube feet

Question 9

How does coelom function in this phylum

Answer 9

circulation, respiration and excretion
fluid circulated by cilia on the peritoneum lining the eucoleom

Question 10

how does this phylum excrete and do gas exchange

Answer 10

excretion and gas exchange via papulae and tube feet which project out between ossicles

Question 11

What is endoskeleton consist of

Answer 11

dermal ossicles: little plates under skin, jointed by connective tissue, muscle
some project outward as spines

Question 12

what are pedicellariae

Answer 12

Small pincers extending from skin (only sea stars and
urchins)
Clean skin of debris, protect papulae, may aid in food
capture in some
In sea stars and urchins only

Question 13

What is most common type of repro (dioecious or monoecious)

Answer 13

mostly dioecious

Question 14

what is autotomy and how does it happen

Answer 14

where organism regenerates itself
all it needs is one arm and a 1/5th of oral disc

Question 15

what is in class crinoidea

Answer 15

sea lilies and feather stars

Question 16

explain sea lilies and feather stars

Answer 16

Both start out attached to the substrate
much of life sessile
Arms are tentacle-like with leathery skin and small
branches and mucus for trapping and eating
suspended phytoplankton

Question 17

What group first introduces secondary radial symmetry

Answer 17

echinoderms which was adaptated for feeding

Question 18

example of class asteroidea

Answer 18

starfish

Question 19

how do starfish feed

Answer 19

predators with eversible stomach; insert cardiac stomach into open bivalve shell to digest and absorb soft parts

Question 20

how are tube feet used in feeding

Answer 20

used to grip bivalve shells so shells can be pulled apart

Question 21

what is in class echinoidea

Answer 21

sea urchin

Question 22

what is unique about oral surface in sea urchins

Answer 22

oral surfaces has expanded around to the aboral side
fused dermal ossicles form a rigid test with long moveable spines tube feet and pedicellariae

Question 23

in sea urchin what is Aristotle’s lantern

Answer 23

complex 5 part jaw structure
used to graze; feed on algae

Question 24

what is also in class echinoidea

Answer 24

sand dollar

Question 25

what does sand dollar have and do

Answer 25

very small spines used to burrow just below
the sand
rigid test, with tube feet, and pedicellariae
Organic particles settle on aboral surface,
and cilia move them down to mouth
HAVE TEETH

Question 26

what is largest class of echinoderms

Answer 26

class ophiuroidea

Question 27

whats in class ophiuridea and where are they abundant

Answer 27

brittle stars and basket stars
abundant in oceans, often covering sea bottom

Question 28

what type of feeding so class Ophiuroidea do

Answer 28

detritivores; feed on decaying matter and plankton via movable jaw

Question 29

how does class Ophiuroidea have locomotion

Answer 29

moveable arms

Question 30

unique features of ophiuroidea

Answer 30

no intestine or anus (incomplete digestive system)
no pedicellariae or papullae
autotomy is best in this class

Question 31

what is in class Holothuroidea

Answer 31

sea cucubmbers

Question 32

what is pedicellariae

Answer 32

small wrench or claw shaped appendage with moveable jaw

Question 33

what is papillae (Papula)

Answer 33

dermal branchia or skin gills

Question 34

how do Holothuroidea differ from echinoderms

Answer 34

greatly elongated on oral-aboral axis
ossicles reduced so body is soft
arrangement of tube feet modified for crawling

Question 35

how do holothurdoidea feed and defend themselves

Answer 35

feed by picking up food or trapping food on tentacles and stuffing in mouth
to defend they expel parts of viscera which are sticky and may contain toxins
or they can throw up their digestive system

Question 36

water oxygen and nutrients are circulated in the echinoderms by

Answer 36

ciliated peritoneum

Question 37

radial symmetry first evolved in echinoderms for the purpose of

Answer 37

sessile filter feeding

Question 38

what is ossicle

Answer 38

boney plate that make up endoskeleton

Question 39

what are sand dollar teeth

Answer 39

broken Aristotle’s lantern