Echinodermata

Question 1

Echinoderm classes

Answer 1

Asteridea - starfish
Crinoidea - crinoids and featherstars
holothuroidea - sea cucumbers
ophiuroidea - brittle stars
echinoidea - sea urchins

Question 2

Water vascular system

Answer 2

system of internal ciliated canals linked to tube feet, tube feet muscular can bend in different ways, madreporite serves as an intake of seawater to replenish leakage at the tip

Question 3

Structure of Echinodermata

Answer 3

Mouth is on underside, endoskeleton is a lattice of rods and plates bound by connective tissues, each ossicle is formed by a single crystal

Question 4

Feeding of Echinodermata

Answer 4

mainly on bi-valves, starfish tissue and skeleton stiffen allowing them to use their tube feet to force open bivalve, inserting their eversible stomach and begin digestion

Question 5

Structure of Echinoideas

Answer 5

No arms, skeletal ossicles interlinked to form solid test, surface covered in moveable spine (sea urchins)

Question 6

Regular echinoids structure

Answer 6

Globose test and long spines. ambulacral area with tube feet arranged in meridians around the test and alternative with interambulacral area

Question 7

irregular echinoids

Answer 7

adapted to burrow - mainly desposit feeders, tube feet being used for food collection and transport, aboral tube feel function in gas exchange

Question 8

Class holothuroidea

Answer 8

Body cylindrical due to elongation along oral/aboral axis, tube feet around mouth highly modified as buccal tentacles, deposit and suspension feeder