Echinodermata

 

 

echinoderms:

Overview L77

      slides:

starfish pedicellaria  L79 Fig 11.8; T496 Fig 20.11; R75

starfish bipinnaria larvae  L14 Fig 2.2(l); T506 Figs 20.22 & 20.23; R110

starfish arm c.s. L79 Fig 11.9c; L80 Fig 11.13; T494 Fig 20.7; R75 Fig 75e – papula (= skin gill or dermal branchia), ampulla, ossicles 

      external anatomy of:

sea star   L76 Fig 11.8; T494 Fig 20.6; R75 – spines, arm, central disc, madreporite, mouth, spines, tube feet, ambulacral grooves

sea lily (in plastic block) T489 Fig 20.3 – arm, pinnules

sea urchin c.s. L81 Figs 11.14 and 11.15; T501 Fig 14.12 – spines, mouth, pedicellaria, madreporite, Aristotle's lantern

Questions for your lab notebook

 

What are the two functions of the unique water vascular system of echinoderms?

 

 

 

What role does the madreporite play in the water vascular system of echinoderms?

 

 

 

Why are ossicles classified as an endoskeleton?

 

 

Which of the following structures in echinoderms does not play a role in gas exchange?

a) dermal branchia

b) respiratory tree

c) Aristotle's lantern

d) coelomic fluid

 

What factors have led zoologists to determine a close evolutionary relationship between modern echinoderms and chordates (our own phylum)?

 

 

 

Explain how radial symmetry and the lack of cephalization can have adaptive value for sessile animals and be favored by natural selection.