Introduction to Zoology WEEK 12

(11/8-11/12)

November 8, 2004

Phylum Enchinodermata – continued from week 11 All Marine – Body fluids are Isosmotic to the sea water – Gastrovascular system – Tube Feet are oriented and move via a combination of muscles and water pressure. Know the cross section images from your book! The ampullae and the tube feet. In the Echinoidea - Aristotle’s Lantern – the picking grinding mouthparts of the sea urchin. Class Asteroidea

• True Sea Stars – originally bilaterally symmetrical but have secondarily derived pentamerous symmetry.

• Body tissues all isosmotic with sea water –

Class Echinoidea • Urchins

o Regular – rounded are used for food by Asian peoples o Irregular – examples are the sea biscuit and the sand dollar.

An echinopleuteus of a sea urchin!

Sand dollars – irregular urchins – the test only! (test is the shell of the urchin)

Strongylocentrotus purporatus- Pacific N.W. Urchin purporatus (purple) Class Holothuroidea

• Sea Cucumbers (fig/ 14.16) • Self evisceration • 3o Bilaterally Symmetrical from a bilaterial larval form to a

radially symmetrical form to a bilaterally symmetrical form for the adult!

Class Crinoidea • Sea Lilies • Feather Stars

Class Ophiroidea • Brittle Stars • Most # of species = most speciose

Phylum Chordata

• Bilaterally symmetrical • Well developed/defined coelom – True coelom {Eucdelic} • Body Cavity lined w/ mesodermally derived peritoneum

_____________________________________________________________ November 10, 2004 Synapomorphies of Chordates

• Notochord – flexibility for animal – provides rigidity. • Dorsal Hollow Nerve Cord (DHNC) • Pharyngeal Gill Arches (pouches)

o Chordates have or manifest these chars @ some stage in development.

• Post Anal Tail • Complete digestive system.

Super Phylum Urochordata • Tunicates • Salps • All marine • Tunic – body protective covering • Solitary feeders – suspension feeders • Filter feeders • Page 292 see that page for more details on the urochordates –

Subphylum Cephalochordata = Craniata • Vertebral column

o Composed of serially repeating units of bone or cartilage in some cases + vertebrate.

• Cranium

Super Class Agnatha (‘No Jaw”) Class Mxini (slime fish)

• No Jaw • Hagfish – blind – detect food by smell – predatory • Marine • Detritus feeders – eat dead stuff

Pacific hagfish -

Class Cephalospidomorphi • Lamprey – ectoparaties • Feed on salmoid fishes

Petromyzon:

November 12, 2004 Petromyzon (Lampreys)

• 22 species in N.A. o Only 11 parasitic

Superclass Gnathostomata Class chondrichthyes (850-900) (Sharks, skates, rays) Squalus – dogfish shark

- Chondrocranium

Chondrocranium of Squalus

Sharks and Rays

• Spiral intestine o Increase surface area = absorptive surface

spiral intestine photo vx. Diagram.

Elasmobrachii

• Rays and sharks • ALMOST ALL MARINE

o Few F.W. à Pomatotrygon – freshwater sting ray • Originally ancestors marine

o Captive of some species in to F.W. o Endosymbionts also made the change into F.W.

• Sharks have continuously growing teeth

Pomatotrygon – with tapeworms – of course! Fresh Water South America

Urolophus halleri the round stingray – I described new species of Eimeria from these